Net-Zero Energy Consumption Building in China: An Overview of Building-Integrated Photovoltaic Case and Initiative toward Sustainable Future Development

Abstract

Carbon-neutral strategies have become the focus of international attention, and many countries around the world have adopted building-integrated photovoltaic (BIPV) technologies to achieve low-carbon building operation by utilizing power-generating building materials to generate energy in buildings. The purpose of this study is to review the basic status of the development of building-integrated photovoltaic (BIPV) technologies in China, to identify and analyze the existing problems and challenges, and to propose optimization strategies and methods so as to better promote the overall development of green buildings and net-zero energy consumption buildings in China and the world. Primarily, the research area of BIPV is focused on the Chinese region through a case study approach. Subsequently, it elaborates on the theoretical basis of zero-net energy buildings and BIPV as well as the current status of the construction of the world’s low-carbon building standard system, and it summarizes the annual electricity generation of zero carbon buildings adopting BIPV in some European countries. Then, the article further quantitatively and comprehensively analyzes six successful BIPV application cases in China, and it graphically and visually evaluates and demonstrates the average annual net-zero energy performance percentage of the application cases by using the EPI evaluation and measurement tool. At the same time, based on the results of the above assessment, the challenges facing the development of BIPV in China are summarized, and specific incentives for new BIPVs are proposed to address the challenges as well as strategic approaches to optimize BIPVs that are applicable to China as well as Europe and the US. Ultimately, it is concluded that several classic BIPV building cases have achieved essentially 100% net-zero energy operation and maintenance with significant reductions in CO₂ emissions and savings of tens of thousands of tonnes of coal consumption. This shows that BIPV technology is gradually developing and maturing in China, and there are great advantages and incremental development space for promoting BIPV in China in the future. The application and promotion strategy of its results in China is also applicable to other countries in the world. It is hoped that based on this experience, countries around the world will implement the “carbon neutral” strategy and zero-net energy consumption development more efficiently and with higher quality so as to realize a greener and cleaner future.

1. Introduction

The world’s population has grown by 20% compared to 30 years ago. According to data released by the United Nations on the Global Population Prospects Report 2050, the world’s population will be nearly 8 billion by around 2030 [1]. Over the past 20 years, greenhouse gas emissions due to human activities have reached alarming levels. According to the Global Building and Construction Consortium (GlobalABC) 2021 Global Building and Construction Status Report, the construction and utilization of buildings worldwide accounts for 40% of total energy use, 20% of land use, 20% of water use, 30% of raw material use, and produces 30% of solid waste and 20% of wastewater. The real estate sector accounts for 28% of annual CO₂ emissions, contributing to global warming and poor air quality. By 2030, Indian cities will build about 20 billion square meters of buildings. Without the development of construction technology and materials that reflect sustainable innovation, the sector will consume the few remaining energy and materials on the earth, causing great damage to the environment [2].

Similarly, according to the International Energy Agency’s 2022 industry report “World Energy Outlook 2022”, China’s pace of emissions reductions in the coming decades will also be an important factor in global efforts to limit global warming to 1.5 °C. China’s power sector is critical to China’s strategic plan to peak CO₂ emissions by 2030 and achieve carbon neutrality by 2060 [3]. In September 2020, the Chinese government made a solemn commitment to the international community to strive to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060 so as to promote the green recovery of the world economy after the epidemic [4].

What is more, the International Energy Agency (IEA) also has data in the 2019 Global Engineering Index (Global Index) that the building sector is one of the important areas of carbon emissions, accounting for 39% of total global carbon emissions and 36% of final energy consumption. In this context, how to reduce energy consumption and greenhouse gas emission intensity per unit of building area in the whole society through the development of green and low-carbon technologies, optimization of energy-saving design, and improvement of energy efficiency level has become an urgent problem for all countries to solve. Achieving zero energy consumption in the building sector is crucial for many countries around the world to achieve carbon neutrality [5].

The aim of this study is to review the net-zero energy operation and maintenance of classic BIPV cases in China, identify and analyze their existing problems and challenges, and propose optimization strategies to better promote the overall development of green and net-zero energy buildings in China and the world. Therefore, the BIPV research area will be focused on the Chinese region through the selection of case study methodologies and evaluations. Firstly, the theoretical basis of net-zero energy buildings and BIPV will be elaborated along with the current status of BIPV construction in Europe and the United States and the annual power generation. Then, we quantitatively and comprehensively analyze six successful BIPV application cases in China, and we evaluate and visualize their annual net-zero energy performance using the EPI assessment and measurement tool. More importantly, based on the above, the current challenges of developing BIPV are derived, and corresponding incentives are proposed as well as strategic approaches to optimize BIPV, which will not only strongly boost the popularity of BIPV in China but also apply to other countries around the world, effectively and with higher quality promoting the “carbon neutral” strategy and net-zero energy consumption development.

2. Review Methodology

Currently, more than half of the world’s carbon comes from fossil fuel combustion, which consumes vast amounts of natural resources. As this trend continues, it is even more urgent, since the demand for resources will increase even more than ever before. In order for this growing population to survive, the global construction industry is expected to grow at an unprecedented rate. These buildings are providing great convenience and workplaces for humans. However, with the increasing demand for higher comfort, the energy consumption of buildings is rising rapidly. According to the 2021 Global State Report on Building and Construction, 230 billion m² of new buildings will be built in the world in the next 40 years [6]. The combined share of the building and construction sector in world energy consumption is close to its share of carbon dioxide emissions. Since 2015, the world’s energy use in buildings has been increasing at an average annual rate, and building-related CO₂ emissions have also increased at an average annual rate [7]. Therefore, reducing CO₂ emissions in the building field and achieving full-cycle zero energy operation has become one of the effective ways for countries to promote “carbon neutrality”, because the construction of zero energy consumption buildings creates energy for the subsequent operation of the building itself under the premise of ensuring energy saving. At present, many countries in the world use building-integrated photovoltaic technology to achieve building energy creation by installing photovoltaic power generation modules on the periphery of buildings so as to achieve the low-carbon operation of building projects and materials.

Methodology for Case Studies Selection

As Asian countries, especially China, have been striving to reduce CO₂ emissions in recent years, and in order to achieve this goal, China continues to explore the critical role that BIPV sustainable buildings can play in addressing the increase in CO₂ emissions, with a wide range of successful BIPV projects. Exploring the establishment of a BIPV system using China as an example can provide insights for other countries around the world, especially developing countries. The selection of case studies comes from recent successful BIPV applications in China, which are low carbon, zero energy and sustainable. These projects aim to provide researchers with a learning model for sustainable design and contribute to the process of carbon neutrality policies to reduce emissions and mitigate climate change. Case study selection is based on important data available from national/international publications, research articles, review articles, conference proceedings, and doctoral degrees published on official government and research websites in China. Only buildings that are considered BIPV will be selected based on their energy-saving/consumption-reduction strategies for different climatic regions in the Asian region [8].

At the same time, according to the recommendation of the latest case of the Chinese BIPV built by a variety of online search platforms, the following were selected for comprehensive analysis and comparative verification of photovoltaic system data, as shown in Figure 1: the Haixi Solar Photovoltaic Exhibition Hall, the Shenzhen Dameisha Vanke Center, the Datong Future Energy Museum, the Shanghai World Expo Theme Pavilion, the Xiuzhou Photovoltaic Technology Exhibition Hall and the Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation. Subsequently, the advantages of applying BIPV in China are summarized, and the above cases are evaluated. Then, based on the above analysis, we reflect on the existing challenges of implementing BIPV in China. Finally, specific incentive measures for applying for additional BIPV, as well as discussion and hypothesis sessions, are proposed according to the challenges.

3. Theoretical Basis of Zero Energy Consumption Buildings and BIPV

3.1. Overview of the Links between Net-Zero Energy Buildings and Photovoltaic Buildings

The so-called zero energy building is an ultra-low energy and zero energy building that does not consume conventional energy and relies entirely on renewable energy such as solar energy, and in the process of using energy-saving technology, zero energy building is one of the trends in future building development. The independence of fossil fuels, and thus renewable energy sources usage, is the key principle of zero energy construction. Zero energy consumption buildings have significant economic benefits, such as the release and implementation of China’s GB/T51350-2019 (Near-Zero Energy Building Technical Standard), which has made China’s building energy conservation enter the era of ultra-low, near-zero and zero energy consumption [9]. The main way to achieve zero energy consumption in buildings is to use the characteristics of the building itself to create energy, and the widely used technology is building-integrated photovoltaics (BIPVs). The so-called building-integrated photovoltaics integrate the photovoltaic system with the building body to achieve “integration”, that is, BIPV encompasses the “integration” of the photovoltaic system and the building body. However, due to the limitations of photovoltaic power generation characteristics and the function and appearance of the building itself, there are still some problems in its implementation; in particular, the traditional photovoltaic power generation system is difficult to incorporate as photovoltaic modules [10].

3.2. Characteristics of Photovoltaic-Integrated Buildings

Building-integrated photovoltaic (BIPV) technology is a combination of solar photovoltaic power generation technology and buildings, which can be used as the envelope of the building, and it can also convert sunlight into electricity to supply the building, while the rest of the energy can be transmitted to the city grid [11], as shown in Figure 2.

The following benefits are associated with building-integrated photovoltaics:

• Double efficiency while conserving land. Building-integrated photovoltaics can significantly lower conventional power usage and boost power efficiency because renewable energy power supply is intermittent and unpredictable. The power generation per unit area can be improved by strategically placing photovoltaic rooftops, allowing for the full utilization of renewable energy sources including wind, photovoltaics, and biomass energy [12]. This technology can also alleviate the energy crisis to a certain extent, and it is also conducive to energy conservation and emission reduction. Due to the acceleration of the construction of modern urbanization projects in China, land is becoming increasingly scarce. The combination of photovoltaic systems and buildings can be developed and utilized to the greatest extent, so it is particularly suitable for promotion and application in large and medium-sized cities [13].
• Clean, green and sustainable. Different from traditional fossil energy, using solar energy to achieve the goal of green, sustainable and zero emissions is a truly environment-friendly energy resource. Moreover, it does not produce pollution, will not cause greenhouse effects, and has no adverse impact on the human living environment. In the context of global climate change, solar energy, as a renewable new energy, will become an important part of future energy construction [14].
• The form is original and distinctive. Green energy conservation and environmental protection are current concepts. People now have higher expectations for life quality. The incorporation of photovoltaic structures can enhance the exterior design of urban structures and give them a new aesthetic appeal [15].
• Fill the valley after cutting the summit. Due to its sporadic and intermittent nature, photovoltaic power generation can be adjusted to the power demand in order to increase the efficiency with which electric energy is used. Additionally, it can successfully lessen the phenomenon of wind and light abandonment, which is advantageous for environmental protection and energy conservation. Additionally, it can help power consumers save money on their electricity bills. Summertime brings high temperatures and a significant urban heat island impact. Incorporating photovoltaic technology into urban building systems can not only lessen the urban heat island effect but also help to supplement the city’s electrical grid [16]. The concept map of zero carbon photovoltaic city integration is shown in Figure 3.
• At the same time, there are some limitations and deficiencies regarding the development of BIPV in China. First, as a policy-dependent industry, the relevant incentive policies have a huge impact on the PV industry. There is insufficient regulatory support in the building sector, and market responsiveness is low. Secondly, the intersection of PV and construction and other industries is not close enough, and the interactive linkage heat with related other fields needs to be strengthened. Third, China’s current BIPV application popularity is more in the large-scale government and corporate public projects because of the high cost of materials and installation, resulting in the current civil BIPV popularity not being high enough. But the above shortcomings mean that BIPV will have a huge incremental space in China in the future due to policy and sustainable development as well as other reasons.

3.3. PV Module Selection and Analysis

According to the main types of process technology and conversion efficiency, photovoltaic modules are divided into monocrystalline silicon cells, polycrystalline silicon cells and amorphous silicon thin-film cells [17]. The photoelectric conversion efficiency of several photovoltaic products is shown in

Table 1. Photovoltaic product photoelectric conversion efficiency.

Photovoltaic Cells	Experimental Theoretical Efficiency	Practical Application Efficiency
Single-crystalline silicon photovoltaic cells	24.8%	17.51%
Polycrystalline silicon photovoltaic cells	20.4%	16.59%
Amorphous silicon thin-film photovoltaic cells	12.9%	6.5–8.5%

.

Amorphous silicon thin-film photovoltaic cells are mostly used on the surface of buildings because of their flexibility, and the efficiency of photoelectric conversion is lower than that of crystalline silicon; the process technology needs to be further improved. Crystalline silicon photovoltaic cells dominate the market and are widely used. First, raw material resources are abundant, physical properties are stable, and environmental pollution is small. Second, the research and development technology is relatively mature and improves the construction efficiency. Third, there is still a lot of research needed in relation to reducing production costs. In the current photovoltaic industry, crystalline silicon cells rely on the advantages of economy and conversion efficiency, occupying more than 95% of the market in the photovoltaic industry [18]. Compared with the low photoelectric conversion efficiency of amorphous silicon thin-film photovoltaic cells, the photoelectric conversion efficiency of monocrystalline silicon solar cells is the highest of all cells in all markets, mostly maintained between 18 and 25%, and the conversion efficiency of monocrystalline silicon photovoltaic modules made by it is now 17.5~18.5%.

There are two main types of monocrystalline silicon photovoltaic modules mainly used in photovoltaic power generation systems, namely 165 mm × 165 mm cell size pieces in packages of 60 and 70 pieces. Their monolithic module power corresponds to 255–300 W and 285–330 W, respectively. At present, the optical conversion efficiency of 255 Wp in the market is about 15.58%, while that of 260 Wp is about 15.88%, that of 265 Wp is about 16.20%, that of 270 Wp is about 16.49%, that of 275 Wp is about 16.80%, that of 285 Wp is about 17.41%, that of 290 Wp is about 18.02%, and that of 300 Wp is about 18.33%. In the case of little price difference, the 285–330 Wp component has higher conversion efficiency than the 255–275 Wp component [19]. Combined with various natural conditions and real infrastructure conditions in China, the large-scale implementation of 290 Wp monocrystalline silicon photovoltaic modules in China is suitable regarding price, floor area, number of modules, post-maintenance [20], etc.; the main performance parameters are shown in

Table 2. The 290 Wp performance parameter table for single-crystalline silicon photovoltaic cells components.

Component Model	LR6-60
Test conditions	STC	NOCT
Maximum power (Pmax/W)	290	213.2
Open-circuit voltage (Voc/V)	38.8	35.9
Short-circuit current (Isc/A)	9.71	7.82
Peak power voltage (Vmp/V)	31.7	29.1
Peak power current (Imp/A)	9.15	7.32
Module efficiency (%)	17.7	17.7
Module dimensions (mm × mm × mm)	1650 × 991 × 40	1650 × 991 × 40

Note: STC (Standard test environment): irradiance 1000 W/m², battery temperature 25 °C, spectrum AM1.5. NOTC (Cell nominal operating temperature conditions): irradiance 800 W/m², ambient temperature 20 °C, spectrum AM1.5, wind speed 1 m/s.

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3.4. The Status Quo of the Construction of Low-Carbon Building Standard System Worldwide

In the United States, since Biden became the President of the United States, he has signed an agreement to join the “Paris Climate Agreement”, saying that he will act quickly on climate change. The United States emphasized that it will take more stringent measures to protect the global environment on which the United States depends, so as to ensure a balance between economic development and environmental protection, and to achieve sustainable development goals. In addition, the United States is also vigorously promoting energy conservation and emission reduction [21]. The U.S. federal government updates voluntary formwork building energy efficiency codes (ASHRAE90.1 and IECC) every three years, and voluntary certification projects (ASHRAE 189.1, LEED certification, DOE zero energy housing certification) have also been implemented in the United States. The U.S. Department of Energy formed a partnership with the Passive House Institute United States (PHIUS) in 2012 to promote the development of the related Zero Energy Ready Home (ZERH) and Passive House Institute United States (PHIUS) plus passive house certification projects, recognizing the importance of passive house standards based on performance indicators [22], and jointly promulgated “Climate-Specific Passive Houses”.

The concept of a “passive house” actually originated in Europe, and it was defined in Germany as a building method that can maintain a comfortable indoor environment temperature without active heating and air-conditioning systems, thereby minimizing the building’s dependence on energy systems. After more than 20 years of improvements, the passive house standard system is now used as a reference by governments all over the world [23]. China, which is located in Asia, also issued the “Green Building Evaluation Standard (Trial)” in 2016 to guide and promote the development of building energy conservation. With the acceleration of China’s urbanization process, the “German Energy Conservation Law” also stipulates that all new government public buildings from 2019 should meet the near-zero energy building standards, while all new buildings from 2021 should meet the near-zero energy building standards, and all stock buildings before 2050 should become near-zero energy consumption buildings [24].

The Minergie standard system is a commercial green building certification standard system funded by the Swiss government. It is currently the leading standard in the field of building energy efficiency in the world. It was not only established before most international green building standards with global influence, but it is also in line with the German passive house standard, which pays more attention to high comfort. This normative system has been widely recognized by the global community and has continuously promoted the trend of new standards in the field of architectural design [25].

In summary, various low-carbon building standard systems have proposed low-carbon requirements to regulate building emissions. CO₂ emissions from buildings have a critical impact on global climate change, and building-integrated photovoltaic (BIPV), as an integrated PV and building technology, is an important way to reduce CO₂ emissions from buildings. Many other commercial buildings in Asia and Europe also use BIPV to install photovoltaic power generation equipment on the roof, facade or side to further achieve the goal of zero carbon. According to the distribution area of buildings and the difference of the photovoltaic laying area, there is a large gap in the annual power generation, as shown in

Table 3. Some zero carbon buildings partially paved with BIPV.

Building Name	Location and Construction Year	System Size	Nominal Power	Image Display
ENERGY base office	Vienna, The Republic of Austria (2008)	400 m2	48.2 kWp
Hofberg 6/7	Bern, Swiss Confederation (2011)	294 m2 (Roof); 51 m2 (Facade)	42.84 kWp
Casa Solara	Zurich, Swiss Confederation (2012)	346 m2	34.4 kWp
“Aktiv Energy Tower” Fronius	Wels, The Republic of Austria (2012)	/	38.8 kWp
Umwelt Arena Schweiz, Spreitenbach	Zurich, Swiss Confederation (2013)	5334 m2	737 kWp
Solar Settlement, Hintere Luegeten	Montreux, Swiss Confederation (2013)	720 m2 (Roof); 362 m2 (Facade)	93.25 kWp
Azurmendi Restaurant	Bilbao, The Kingdom of Spain (2014)	283.6 m2	21 kWp
NTT Aoba Dori Building	Tokyo, Japan (2015)	423 m2	20 kWp
J&P Lougheed Performing Arts Centre	Camrose, Alberta Canada (2016)	882 m2	120 kWp
Solsmaragden Office,	Oslo, Kongeriket Noreg (2017)	1242 m2	115.2 kWp
Brynseng Primary School	Oslo, Kongeriket Noreg (2019)	1046 m2	166 kWp
Copenhagen International School	Copenhagen, The Kingdom of Denmark (2021)	6000 m2	700 kWp

The data in Table 3 come from the following sources in order: http://www.solarwatt.de; http://www.fent-solar.com; http://www.mgt-esys.at; http://www.ertex-solar.at; http://www.meyerburger.com; http://www.sanjo.ch; http://www.onyxsolar.com; http://www.lixil.com; http://www.conergy.com; http://issol.eu; http://issol.eu all accessed on 5 August 2023.

, which is a performance introduction of a representative zero carbon building partially paved with BIPV [26].

4. Case Study of BIPV Application in China

At present, located in China, the most representative country in Asia, the China Building Energy Efficiency Federation has formulated the T/CABEE003-2019 “Near-zero Energy Building Evaluation Standard” in 2019, and it has stipulated the building measurement technical specifications and evaluation methods for near-zero energy construction demonstration projects [9]. The code will guide the comprehensive evaluation of the safety performance of near-zero energy buildings across the country, and it will give rectification and treatment measures for unqualified projects. The evaluation process includes three stages: engineering design evaluation, construction evaluation and operation evaluation. Among them, energy conservation assessment refers to the comprehensive analysis of the energy efficiency level of each link of the building’s life cycle [27], and there is also a comprehensive understanding of the gap between its actual performance state and the expected effect.

At present, more than 5 million square meters of near-zero consumption buildings have been built in China. By the end of 2019, 18 demonstration projects in China had achieved the construction results of ultra-low, near-zero energy and far-zero energy consumption. Each demonstration project was designed and constructed according to the technical path of the “Technical Standard for Near-zero Energy Buildings”, all met the technical specification conditions, all used natural conditions according to local conditions [28], and they all achieved the construction purpose of ultra-low and near-zero energy, thus promoting the healthy development of China’s near-zero energy. And from the five dimensions of economic benefits, including functional quality, sanitary comfort, energy efficiency, and ecological value, the existing public buildings’ green transformation building-integrated photovoltaic benefit evaluation index system was constructed and then refined layer by layer to 23 items [29]. Among them, the representative cases of BIPV application in China in recent years are outlined in the following subsections.

4.1. Haixi Solar Photovoltaic Exhibition Hall, Qinghai, China

The Haixi Solar Photovoltaic Exhibition Hall in Qinghai Province, China, covers a building area of approximately 3940 m², with a building elevation of 12.8 m, and a total building area of 4876 m², including two parts: an exhibition space of about 2992 m² and a public service space of about 1884 m². Through the reasonable arrangement of different functional areas and display contents, it forms an organic whole, focusing on the integration of photovoltaic technology and architecture into one. The layout of the PV exhibition hall is divided into five parts, namely, the PV exhibition hall driven by life, the PV exhibition hall providing an in-depth exploration of the history of PV, the PV exhibition hall for demystifying PV technology, the PV exhibition hall for innovative PV technology, and the PV exhibition hall for looking into the future [30].

The total installed capacity of the main body of the building is 195.864 kWp, of which 36 thin-film modules (64 Wp/block) with an installed capacity of 2.304 kWp are used on the light roof of the conference room; 180 thin-film modules (85 Wp each) with an installed capacity of 15.3 kWp are used for the light window, which is of triangular shape; the roof and the ground are equipped with shading devices in order to improve the comfort of the indoor light environment. The roof above the exhibition hall uses 1056 thin-film PV modules (135 Wp each) with an installed capacity of 142.56 kWp, while the southern façade uses 420 thin-film PV modules (85 Wp each) with an installed capacity of 35.7 kWp. Each year, the power generation of the exhibition hall reaches 282,400 kWh, with an annual average of 1441.86 h of comprehensive utilization. The average annual CO₂ emission reduction reaches 254.16 tonnes, which is in line with China’s current GB/T51350-2019 “Near-zero energy consumption building” technical standards [31], as shown in

Table 4. Basic information of the PV system of Haixi Solar PV Exhibition Hall.

Project Title	Haixi Solar Photovoltaic Exhibition Hall
Project Address	South of State Archives, New District, Delingha City, Haixi Prefecture, Qinghai Province, China
Project Photos
Area of building (m2)	4875.68
Area of practical building curtain wall renovation (m2)	4200
Total thin-film PV modules (blocks)	1692
PV module (panel) type	Monocrystalline Modules, thin-film modules (64 Wp/block, 135 Wp/block, 85 Wp/block)
Total installed capacity (kw)	195.864
Total peak power (kw)	237
Reduction in annual energy consumption of building heating systems (kWh)	1,036,000
Reduction in annual electricity consumption of air-conditioning and refrigeration systems in buildings (kWh)	1,101,360
Annual electricity generation (kWh)	282,400
Net annual energy consumed (kWh/year)	273,000
Average annual combined utilization hours (h)	1441.86
Average annual CO2 emission reduction (t)	254.16
Types of “PV+”	PV + Building (Public)

The image comes from the following sources: https://www.xianjichina.com/special/detail_407084.html; http://www.jiapv.com/category/201809/14/49809.html all accessed on 5 August 2023.

.

The structure used in this classic case is the open frame PV curtain wall structure system, which is generally divided into aluminum alloy columns, aluminum alloy beams, aluminum alloy pressure plates, PV glass, PV cables and stainless steel spring pins. It also has a higher flexural load bearing capacity and better deformation performance than other curtain wall structures. Under the influence of external loads such as gravity loads, vibration loads and wind loads, the loads can be transferred to the main concrete elements via the aluminum alloy pillars to ensure the safety of the whole structure system [31], as shown in Figure 4.

The project revolves around the themes of solar energy-driven innovation, integration of architectural shape and photovoltaic power generation, photovoltaic products exhibition display, popular science education and the new energy field of science and technology exchanges as a whole. The solar energy science and technology education base will show the country as well as the world the Hercynian photovoltaic represented by the new energy industry’s development history, guide enterprise to adopt advanced technology, develop high-quality photothermal resources, and advocate for the application of clean energy and Hercynian low-carbon environmentally friendly advanced concepts.

4.2. Shenzhen Dameisha Vanke Center, Shenzhen, China

In order to meet the requirements of the EA C2 (On-site Renewable Energy) provision in the American Green Building Council’s LEED Green Building Assessment System, which requires renewable energy constituting 12.5% of the building’s annual energy consumption, the design of Vanke’s headquarters will use solar energy [32]. Dameisha 1000 Vanke Center is located in Dameisha Seaside Tourist Resort, Yantian District, Shenzhen, Guangdong Province, with a land area of 61,700 m² and a total construction area of about 120,000 m². It is divided into four parts, of which the Vanke headquarters part is about 14,400 m², and the design directly connects solar power generation with the low-voltage bus of the dedicated power transformer in the headquarters part. According to the data statistics, the total peak power of the solar power generation project of Vanke Centre is 282 kW, using a total of 1567 monocrystalline silicon panels, 32 sets of inverters and 40 sets of complete sets of electrical equipment. The whole solar power project is divided into three parts: the main grid-connected photovoltaic power station, the LED garage-independent lighting system, and the photovoltaic clean contrast system, as shown in

Table 5. Basic information of rooftop photovoltaic system of Dameisha-Vanke Centre.

Project Title	Shenzhen Dameisha Vanke Center
Project address	Vanke Centre, 33 Huanmei Road, Dameisha, Yantian District, Shenzhen, China
Project photos
Area of building (m2)	14,400
Area of photovoltaic panels laid (m2)	8000
Monocrystalline silicon panels (blocks)	1567
Inverters (sets)	32
Sets of electrical equipment (sets)	40
Total peak power (kw)	282
Average annual sunshine (h)	1933.8
Solar radiant energy on the horizontal plane (kW/m2a)	1451
Annual electricity generation (kWh)	307,371
Net annual energy consumed (kWh/year)	1,999,200
Average annual CO2 emission reduction (t)	306.4488
Types of “PV+”	PV + Building (Office)

The image comes from the following sources: https://www.sohu.com/a/324324337_365929; https://www.zcool.com.cn/work/ZMzczODc0MTY=.html all accessed on 5 August 2023.

[33].

At present, there are two main ways for public buildings to use solar energy resources, namely solar water heating and solar photovoltaic power generation. Considering that Vanke headquarters is a building with mainly office functions and the demand for hot water is not large, solar energy resources will be used through solar photovoltaic power generation in the design of Vanke headquarters. The use of the solar photovoltaic grid-connected power generation system will provide more than 12.5% of the annual energy consumption of Vanke Center headquarters [34].

Next, we provide an estimation of the power generation of Vanke headquarters’ grid-connected power generation system. Solar photovoltaic power generation systems generally need to simulate and calculate their annual power generation according to special calculation and analysis software [30], which is more complicated, and the estimation method can generally be used. Considering η = PV module efficiency × inverter efficiency × (1-DC line loss rate), × other efficiency = 16.7% × 98% × (1 − 1%) × 80% = 12.96%, including the influence of other factors such as cable joint contact resistance, the total line loss in this project does not exceed 1%. Other efficiencies include AC distribution loss, dust on the solar cell conversion efficiency, etc.; then, Q = (1200 × 1.58 × 0.798) × 1451 × 12.96% kW·h = 196.01 × 1451 kW·h = 284,520.5 kW·h [35]. And according to the above formula, the total annual power generation of the Vanke solar power project is about 307,371,000 kWh under the annual average sunshine duration of 1933.8 h, while the annual average CO₂ emission reduction is as high as 306.4488 tonnes as measured by the relevant calculations [36]. Therefore, the final energy efficiency of the attempt is fully compliant with the current Chinese policy standard GB/T51350-2019 Technical Guidelines for Near-Zero Energy Buildings [33], as shown in Table 5.

4.3. Shanxi Datong Future Energy Museum, Shanxi, China

The Future Energy Pavilion building covers an area of 15,000 m² and is a comprehensive pavilion integrating an energy-strategic planning pavilion, energy civilization dissemination pavilion, energy revolution demonstration pavilion, energy science education pavilion, energy life experience pavilion and energy technology demonstration pavilion, constituting “six pavilions in one”. It is also the largest ultra-low energy consumption passive building [37]. The energy hall has set up a total of four sets of BIPV systems: except for part 2, which adopts standard high-efficiency crystalline silicon photovoltaic modules (conversion efficiency >20%), the remaining components are all BIPV photovoltaic components to meet the building’s requirements for the size, color, light transmittance, structural safety, repairability and replacement, aesthetics without showing nails and other performance requirements [38]. Using the visualization characteristics of BIM technology, the façade photovoltaic components are designed according to the unit installation concept of three blocks to ensure installation accuracy and flatness as well as improve the efficiency of on-site installation. According to the statistics, the total installed capacity of the photovoltaic system in this energy museum is more than 900 kW, with an annual power generation of about 1.23 million kWh, while the annual energy consumption of this building is predicted to be 1,457,532.42 kWh through simulation, and the annual power generation from renewable energy sources is 1,230,036.50 kWh, which accounts for 84.39% of the annual power consumption of the building, and the net energy consumption of each square meter of the building is about 98.59 kWh per year. The annual net energy consumption per square meter of the building is about 98.59 kWh, which finally achieves the near-zero energy consumption index stipulated in China’s current GB/T 51350-2019 technical standard for near-zero energy buildings [39], as shown in

Table 6. Basic information of photovoltaic system of the Future Energy Pavilion in Datong, Shanxi, China.

Project Title	Datong Future Energy Exhibition Centre
Project address	International Energy Revolution Science and Technology Innovation Park, Datong City
Project photos
Area of building (m2)	29,000
Area of photovoltaic panels laid (m2)	10,700
Photovoltaic module (panel) mounting position	Roof photovoltaic system, east façade photovoltaic system, west facade photovoltaic system, south facade photovoltaic system, light roof photovoltaic system
Monocrystalline silicon photovoltaic modules (sets)	1340 Blocks (410 Wp), 926 Blocks (320 Wp), 1405 Blocks (40 W)
Thin-film photovoltaic modules (sets)	1405 Blocks (40 Wp), 160 Blocks (100 Wp)
Intelligent convergence boxes (sets)	23
DC–DC converter 50 kW (set)	18
Total DC load power (kW)	1107
Total installed capacity (kW)	980 k
Proportion of annual electricity consumption in buildings (%)	84.39
Comprehensive building energy efficiency rate ηp = [ED − ER] × 100%/ER (%)	100
Energy saving rate of the building itself ηe= [EE − ER] × 100%/ER (%)	31.71
Annual electricity generation (kWh/year)	1,230,036
Net annual energy consumed (kWh/year)	1,300,000
Average annual CO2 emission reduction (t)	1086.47
Types of “PV+”	PV + Building (Public)

The image comes from the following source: https://www.architechcn.com/news-view-3131.htm accessed on 5 August 2023.

.

The curtain wall structure used in this exemplary case is a hidden frame PV curtain wall aluminum column structure. As the PV curtain wall structure must be in full contact with the sunlight in order to optimize the photovoltaic conversion effect, the hidden frame PV curtain wall construction method effectively prevents the structural system from blocking the sunlight, thus reducing its impact on the PV conversion effect. At the same time, according to the practical application experience, the hidden frame PV façade has a better heat insulation performance and waterproof effect, and the construction is simple, facilitates fast installation, and can save costs, which is in line with the concept of green energy saving and environmental protection [40]. Therefore, many of the existing PV curtain wall projects use the hidden frame PV curtain wall structure, as shown in Figure 5.

4.4. Shanghai World Expo Theme Pavilion, Shanghai, China

The roof of the Theme Pavilion building in Shanghai presents a unique urban texture, demonstrating the sense of rhythm and space that is unique to large exhibition buildings. The building uses photovoltaic modules to form 18 rhombuses of 36 m long and 72 m wide and 12 triangles of 36 m long and 36 m wide, which are set horizontally on the roof, creating an effect of convergence of light and shadow. At the same time, it adopts the “wave” design method, organically combining the original isolated and disorderly buildings, perfectly integrating and coordinating with the surrounding buildings, presenting a new charm [41].

In the application of the Shanghai World Expo theme pavilion, the photovoltaic building integrated grid-connected system adopts a combination of photovoltaic and building technology, photovoltaic building-integrated module technology and high-power grid-connected inverter technology and other technologies [42], which are united with the architectural, ecological, material and other technologies in the theme pavilion building. It has also become a vivid teaching material for the popularization of high technology in China in the past decade [42], in which the zero energy consumption green building concept has become the key to the people of China. The zero energy consumption green building concept has played a positive role in promoting environmental protection and energy conservation awareness among the nation’s people. In order to ensure that the light needs of the glass roof below are met, the photovoltaic module array above the central channel of the Theme Pavilion is made of light-transmitting polycrystalline silicon photovoltaic modules encapsulated with double-sided glass [43]. The total installed area of solar modules is 30,000 square meters, with a total installed capacity of 2825 kW and 16,250 polycrystalline modules, as shown in

Table 7. Basic information of photovoltaic system in the Theme Pavilion building of the World Expo in Shanghai, China.

Project Title	Shanghai World Expo Theme Pavilion
Project address	No. 1099 Guozhan Road, Pudong New Area, Shanghai, China
Project photos
Area of building (m2)	129,000
Area of photovoltaic panels laid (m2)	30,000
Double-sided glass encapsulated light-transmitting, multicrystalline silicon photovoltaic module (block)	16,250
Total installed capacity (kW)	2825
Application scale (MW)	2.8
Total peak power (kW)	2597
Inverters (units)	1500 kVA three-phase converter, 1250 kVA three-phase inverter, 20,100 kVA three-phase inverters, 26 kVA single-phase inverters, 55 kVA single-phase inverters
Annual electricity generation (million kWh)	3,000,000
Net annual energy consumed (kWh/year)	2,870,000
Average annual CO2 emission reduction (t)	2500
Standard coal saved (t)	1000
Types of “PV+”	PV + Building (Public)

The image comes from the following sources: www.tandd.cn/show/structure/page/3/; http://m.lightingchina.com.cn/news/49591.html all accessed on 5 August 2023.

[44].

This large-scale photovoltaic building-integrated grid-connected power generation system is the largest in Asia, with an installed capacity of 2.83 MW. The design stage of the Theme Pavilion building considered the characteristics of the building, taking into account the application of various types of photovoltaic systems to achieve the solar energy utilization technology as far as possible regarding human life, work, and activities combined [45]. The result fully reflects the perfect combination of solar energy products and buildings, realizing the harmonious unity of effectiveness, practicality, aesthetics and economy.

A variety of photovoltaic building integration modules are adopted, including integrated modules with roofs and large-area light-transmitting photovoltaic modules. Mutually complementary with the changing building structure, they can ensure the aesthetics of the building but also generate sufficient power to produce green and clean energy, prompting the building to realize zero energy operation and maintenance [46]. We use the system theoretical model calculation to measure the power generation and CO₂ emission reduction in the PV building architecture integration system of the Shanghai World Expo Theme Pavilion. As shown in Table 7, the average annual power generation of the PV building integration system of the China Pavilion, Expo Centre and Theme Pavilions in the expo area is about 2.48 million kWh, and the average annual CO₂ emission reduction is about 2500 tonnes, basically realizing China’s current GB/T 51350-2019 near-zero energy building technology standard [47], as shown in Table 7.

4.5. Xiuzhou Photovoltaic Technology Exhibition Hall, Jiaxing, Zhejiang, China

PV modules were installed in all corners of the Xiuzhou PV Technology Exhibition Hall, including the south facade curtain wall, west facade curtain wall, east facade curtain wall, sloped roof, photovoltaic canopies [48], photovoltaic towers and light roofs. Longyan Energy Technology uses 1729 pieces of CdTe thin-film super-large modules, including 385 pieces of CdTe thin-film modules with a transmittance rate of 50% at 1.2 m × 2.4 m, 336 pieces of CdTe thin-film modules with a transmittance rate of 50% at 1.2 m × 2.4 m in white, 287 pieces of CdTe thin-film modules with a transmittance rate of 50% at 1. 2 m × 1.8 m, and 721 pieces of CdTe thin-film modules with a transmittance rate of 50% at 1.2 m × 1.8 m, for a total area of 425,500 square meters. The thin-film modules have a total area of 4253 square meters and an installed capacity of 310 kW [49]. Meanwhile, 234 various anisotropic CdTe thin-film analogue modules with an area of 1008 m² are installed in this science and technology museum. On the roof of this science museum, 224 crystalline silicon modules with an installed capacity of 58 kW are installed, and the total installed capacity of the project is 368 kW, as shown in

Table 8. Basic information of photovoltaic system of Xiuzhou Photovoltaic Science and Technology Museum in Jiaxing, China.

Project Title	Xiuzhou Photovoltaic Science and Technology Museum
Project address	North of Xiuzhou Hi-Tech Zone Office Building, Xinhe Road, Xiuzhou District, Jiaxing, China
Project photos
Area of building (m2)	8695
Area of photovoltaic panels laid (m2)	5600
CdTe photovoltaic thin film glass, crystalline silicon photovoltaic panels (blocks)	2187 (1963/224)
Photovoltaic module (panel) mounting position	South facade curtain wall, west facade curtain wall, east facade curtain wall, pitched roof, photovoltaic canopies, photovoltaic towers and light roofs
Total installed capacity (kW)	368
Application scale (MW)	0.36
Total peak power (kW)	400
Annual electricity generation (kWh)	500,000
Net Annual Energy Consumed (kWh/year)	379,000
Average annual CO2 emission reduction (t)	546.94
Standard coal saved (t)	203.464
Types of “PV+”	PV + Building (Public)

(The image comes from the following sources: zhuanlan.zhihu.com/p/563824066; www.sohu.com/a/344304631_99897142 all accessed on 5 August 2023).

.

The project adopts cadmium telluride film light transmission components, and the surface color of the components is uniform (pure black); the project has strong integrity, high conversion efficiency, good stability and strong adaptability [50]. According to the characteristics of cadmium telluride thin-film components that are sensitive to light and have good weak light, they are suitable for different installation angles, have little loss of power generation capacity, and also reduce the energy consumption of air conditioning in buildings. Cadmium telluride thin-film solar transmission modules have a large size, many types, high standards [51], difficult module production, and a high degree of customization for both lighting and power generation. According to customer requirements, the products are made into different sizes, including different transmittance and different colors. They perfectly replace the traditional curtain wall glass, truly realize the replacement of architectural glass by photovoltaic glass, and provide the possibility of green and sustainable development for urban buildings. According to statistics, the annual power generation of the photovoltaic system of the Science and Technology Exhibition Hall exceeds 500,000 kWh, with a total peak power of 400 kWh, while the annual average CO₂ emission reduction in the building measured by the simulation formula is about 546.94 tonnes per annum, which is equivalent to the saving of 203 tonnes of standard coal, and ultimately reaches the index of near-zero energy consumption stipulated in China’s current GB/T 51350-2019 “Near-zero Energy Consumption Buildings” technical standard [52].

4.6. Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation, Beijing, China

The Smart Energy Demonstration Project for the headquarters building of the China National Electric Power Investment Corporation (NEPIC) uses integrated smart energy technologies to bring the building’s energy-saving and consumption-reducing efficiency to a new level. Among them, this program takes the lead in adopting photovoltaic energy-saving curtain wall technology to achieve a multi-dimensional integrated application of energy, making building energy conservation and photovoltaic power generation reach an effective complementary state between the building energy consumption, reducing building energy use and at the same time reducing the pressure on the regional power grid power supply, improving the reliability of power supply to the building, enhancing the building’s internal working environment comfort and so on. It is one of the representative classic cases in the region, providing an example for the construction of smart PV buildings in other parts of the world [53].

The building’s curtain wall renovation covers an area of 4200 square meters, including 8600 square meters of interior space. Based on the overall inspection and assessment of the building, the PV energy-saving curtain wall design and related technical solutions were determined. After the renovation, the total installed capacity of the PV curtain wall has been increased to 131 kWp, achieving the goal of energy saving and emission reduction. In practical application, the solar curtain wall can meet the building’s energy-saving requirements and effectively improve the energy utilization efficiency. In 2018, the power generation of the photovoltaic curtain wall reached 107,600 kWh, while the annual power consumption of the building’s air-conditioning and cooling system was reduced by 385,200 kWh, and the annual energy consumption of the building heating system was reduced by 357,200 kWh. In 2019, the photovoltaic energy-saving curtain wall power generation was reduced by 105,400 kWh, while the annual power consumption of the building air-conditioning and cooling system was reduced by 406,300 kWh, and the building heating system’s annual energy consumption decreased by 371,000 kWh. According to the published data conversion, the building achieved zero energy emissions, and its average annual CO₂ emission reduction reached 10.54 tonnes, which is in line with China’s current GB/T51350-2019 “Near-zero energy consumption building” technical standards, as shown in

Table 9. Basic information of photovoltaic system of smart energy demonstration project for the headquarters building of the China National Electric Power Corporation.

Project Title	Smart Energy Demonstration Project for State Power Investment Headquarters Building
Project address	No. 32 South Haidian Road, Haidian District, Beijing, China
Project photos
Area of building (m2)	8600
Area of practical building curtain wall renovation (m2)	4200
Total thin-film PV modules (blocks)	1858
PV module (panel) type	BIPV photovoltaic modules, high-transmittance low-e double-silver LOW-E glass, Hanergy Oerlikon amorphous silicon thin-film photovoltaic modules, Hanergy Copper Indium Gallium Selenide Flexible Modules (Flexible CIGS Modules)
Total installed capacity (kW)	171
Total peak power (kW)	200
Reduction in annual energy consumption of building heating systems (kWh)	371,000
Reduction in annual electricity consumption of air-conditioning and refrigeration systems in buildings (kWh)	406,300
Annual electricity generation (kWh)	105,400
Net annual energy consumed (kWh/year)	65,000
Average annual CO2 emission reduction (t)	104.978
Types of “PV+”	PV + Building (Office)

(The image comes from the following sources: http://www.ilinki.net/news/detail/48753; https://xueqiu.com/4136695324/118350824 all accessed on 5 August 2023).

[54].

The headquarters building of the China State Power Investment Corporation (SIPC) makes full use of photovoltaic (PV) modules for green energy harvesting on the effective area of the building’s facade and roof, and the data show that a total of 1858 BIPV modules are used in the building. The dark part of the building facade consists of non-lighting area BIPV PV modules. Lighting areas are made of high-transmittance, low-emissivity double-silver LOW-E glass. Hanergy Oerlikon amorphous silicon thin-film photovoltaic modules are selected between layers on the south, east and west facades of the building, and Hanergy copper indium gallium selenide (CIGS) flexible modules are selected on the top facade of the building [55]. By combining the utility model with photovoltaic power generation technology, the utility model can not only use the sun that irradiates the surface of the building to generate electricity but also reduce the amount of solar radiation that enters the room so as to achieve the effect of cooling and save the energy consumption of building cooling [54]. At the same time, through the integration of photovoltaic modules in building materials that were manufactured to enhance the building’s thermal insulation performance and further save the building’s summer cooling and heating energy consumption in winter, it is possible to achieve photovoltaic power generation, cooling and warming and energy saving and consumption reduction and other multiple efficacies [56].

5. Evaluation of the Application Advantages of BIPV Cases in China

The China Association for Building Energy Efficiency (CABEE), Green Rating and Integrated Assessment of Habitat Environment (GRIHA) and other rating organizations certify energy-efficient buildings and green buildings.

Table 10. Analysis of annual average net-zero energy consumption strategies used and EPI indices for classical BIPV cases in the context of nZECB in China.

					Strategies Used
Case	Climate	Habitat Type	Area of Building (m2)	Area of Photovoltaic Panels Laid (m2)	Energy Demand Reduction	Renewable Energy	Energy Balance	EPI kWh/m2/yr
Haixi Solar Photovoltaic Exhibition Hall, Qinghai, China [31]	Plateau Mountain	Public	4875.68	4200	Using hollow transparent film components with a transmittance of 25% to 30% for tiling, improving indoor light intensity and reducing indoor temperature and load. Photoelectric glass combined with a ventilation system effectively promotes indoor air circulation, reduces heat, and lowers temperature. Set the north side of the triangular window as a movable window, reduce the indoor temperature through ventilation, and dissipate the residual heat generated by the components.	Building-integrated photovoltaic Solar passive energy Ground source heat pump	100%	55
Shenzhen Dameisha Vanke Center, Shenzhen, China [37]	Tropical Monsoon	Office	14,400	8000	The racking of the PV main grid-connected system is adjustable, set at an inclination of 5° and 25° in summer and winter, respectively, to maximize the use of solar energy. Multi-string and parallel group connection is adopted to ensure the consistency of PV array power generation and improve the balance of power output. The project selects high-quality SMA inverters to ensure the reliability of the system grid-connection, the highest inverter efficiency and the most power output. Optimizing the installation position of the hub box and inverter effectively reduces the DC loss at the DC end and lowers the cost.	Solar PV park Rooftop solar PV Solar thermal DHW Roof garden Rainwater harvesting system	98%	21
Datong Future Energy Museum, Shanxi, China [39]	Temperate Continental	Public	29,000	10,700	High-efficiency fresh air heat recovery is adopted to maximize the possible use of the building roof and facade to maximize power generation and achieve minimum energy consumption. The project’s photovoltaic DC grid-connected capacity is 1 MW, and the total DC load power is 1107 kW, realizing a hybrid system of full DC and flexible DC. The system adopts big data analysis technology to achieve automated operation and maximize the reduction in air conditioning and heating energy consumption.	Roof photovoltaic system Façade photovoltaic system Passive solar energy Ventilation system BIM	100%	44
Shanghai World Expo Theme Pavilion, Shanghai, China [47]	Temperate Monsoon	Public	129,000	30,000	The roof shape is specially treated to better accommodate photovoltaic solar panels, reducing CO2 emissions by about 2500 tonnes per year. Vertical green wall system, through different plants matching, improve the urban heat island effect and reduce indoor temperature and urban drainage load. Adoption of a variety of photovoltaic building-integrated modules. Roof-integrated modules and large-area light-transmitting photovoltaic panels are used.	Building-integrated photovoltaic Roof photovoltaic system Vertical wall system	100%	22
Xiuzhou Photovoltaic Technology Exhibition Hall, Jiaxing, Zhejiang, China [52]	Subtropical Monsoon	Public	8695	5600	The facade and roof of the pavilion adopt CdTe photovoltaic thin-film glass and crystalline silicon photovoltaic panels, which can generate both light and electricity. The pavilion adopts energy-saving and environmentally friendly building materials, and the air-conditioning inside the pavilion adopts a ground source heat pump air-conditioning system to achieve energy saving and emission reduction. A variety of BIPV modules are used, and the total solar power generation power is about 400 KWp, which is a benchmark project for BIPV in China.	Roof photovoltaic system Facade photovoltaic system Building-integrated photovoltaic	100%	43
Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation, Beijing, China [54]	Temperate Monsoon	Office	8600	4200	Photovoltaic power generation technology is adopted to effectively reduce indoor solar radiation and achieve a cooling effect, thus saving building cooling energy consumption. Replacing the original LOW-E glass with BIPV components and high-transmittance, low-emission double-silver-coated glass reduces heat loss. The combination of PV modules and building materials into an integrated system effectively improves building insulation and heat preservation, and it reduces cooling and heating energy consumption.	Rooftop photovoltaic Ground photovoltaic Curtain wall photovoltaic Breeze fans, Energy storage	100%	21

lists six of the most classic and successful cases of BIPV zero energy buildings that have been developed in China in the last ten years according to the climatic distinction, which are classified as Tropical Monsoon, Subtropical Monsoon, Temperate Monsoon, Plateau Mountain, Temperate Continental, and Tropical Rainforest, representing the type of building use, building footprint, operations that consume large amounts of energy, strategies to reduce energy demand, and the type of renewable energy used to meet the energy balance. The types of renewable energy sources used to meet the energy balance ultimately enabled these buildings to achieve an energy balance and an Energy Performance Index (EPI). The energy consumption patterns of the included cases were calculated using the EPI. The EPI was used as a comparative parameter for the energy consumption of the buildings. It is the ratio of a building’s total annual energy consumption to its net floor area [41] (Equation (1)).

$$\mathrm{E}\mathrm{P}\mathrm{I}=\frac{\mathrm{N}\mathrm{e}\mathrm{t}\mathrm{A}\mathrm{n}\mathrm{n}\mathrm{u}\mathrm{a}\mathrm{l}\mathrm{E}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{e}\mathrm{d}(\mathrm{k}\mathrm{W}\mathrm{h}/\mathrm{y}\mathrm{e}\mathrm{a}\mathrm{r})}{\mathrm{G}\mathrm{r}\mathrm{o}\mathrm{s}\mathrm{s}\mathrm{F}\mathrm{l}\mathrm{o}\mathrm{o}\mathrm{r}\mathrm{A}\mathrm{r}\mathrm{e}\mathrm{a}\mathrm{o}\mathrm{f}\mathrm{B}\mathrm{u}\mathrm{i}\mathrm{l}\mathrm{d}\mathrm{i}\mathrm{n}\mathrm{g}\left(\mathrm{S}\mathrm{q}\mathrm{m}\right)}$$

(1)

5.1. Analysis of Annual Average Net-Zero Energy Consumption Strategies Used and EPI Indices for Classical BIPV Cases in the Context of nZECB in China

EPI stands for Energy Performance Index. The EPI is centered around two basic case indices, Net Annual Energy Consumed and Gross Floor Area of Building. It is a tool to measure whether a real-world case has a balanced annual energy consumption index that meets the Net Energy Consumption Index [57], and it is designed to help policy makers, academics and the public better understand and compare the energy performance of different real-world cases [58]. It evaluates net energy building case metrics from a number of countries and regions around the world to produce a value between 0 and 100, which is known as the EPI value. These indicators include the average annual energy consumption, average annual clean energy production, area of building space, area of photovoltaic panels, etc. The higher the EPI value, the better the case performs in terms of the energy consumption index [59], and the results of the analysis can be found in Table 10.

• Haixi Solar Photovoltaic Exhibition Hall, Qinghai, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 100%, and the EPI index is 55, which indicates that the building energy efficiency index of this scheme is very high, and it reaches the standard of zero energy building evaluated by CABEE. At the same time, the scheme has the following design and energy-saving highlights. Firstly, the use of hollow and light-transmitting thin-film modules with a transmittance of 25% to 30% for flat laying significantly reduces direct sunlight to the interior, improves the comfort of indoor light, and reduces the indoor temperature and cooling load. Second, the photovoltaic glass combined with the ventilation system forms a cavity with the exterior surface of the building, which effectively promotes air circulation in the cavity and the building interior, reduces heat in the building interior, and lowers the indoor temperature. Thirdly, the north side of the triangular window is set as a movable window to reduce the indoor temperature through ventilation convection and dissipate the residual heat generated by the work of the components to maximize the appropriateness of the indoor temperature [31], as shown in Table 10.
• Shenzhen Dameisha Vanke Center, Shenzhen, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 98%, and the EPI index is 21, which indicates that the building energy efficiency index of this scheme is high, and it reaches the standard of zero energy building evaluated by CABEE. At the same time, the scheme has the following design and energy-saving highlights. First, the racking of the PV main grid-connected system can be adjusted, and the tilting angle is set at 5° in summer and 25° in winter to maximize the use of solar energy. The tilting angle only needs to be varied twice a year, which will enable the system to generate an additional 3.6% of electrical energy. Secondly, multiple strings and parallel groups are used to ensure the consistency of the PV array and improve the balance of the power output. Third, the project selects high-quality SMA inverters to ensure the reliability of the grid-connected system, with the highest inverter efficiency and the most power output. Fourthly, the project uses 32 inverters. By optimizing the installation location of the hub and inverters, the DC loss at the DC end is effectively reduced, thus reducing the cost [37], as shown in Table 10.
• Datong Future Energy Museum, Shanxi, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 100%, and the EPI index is 44, which indicates that the building energy-efficiency index of this scheme is high, and it reaches the standard of zero energy building evaluated by CABEE. At the same time, the scheme has the following design and energy-saving highlights. First, the use of high-efficiency fresh air heat recovery technology minimizes the building’s heating and cooling demand and achieves a near-zero energy green building under the premise of the maximum possible use of the building roof and facade. The selection of high-efficiency solar photovoltaic systems also maximizes the amount of power generation to achieve the minimum energy consumption. Secondly, the project is designed with a microgrid battery capacity of 2000 kWh, a PV DC grid-connected capacity of nearly 1 MW, and a total DC load power of 1107 kW, which realizes the full DC of the system and makes it a flexible interconnected AC/DC hybrid system of huge scale. Thirdly, the system adopts big data analysis technology to achieve automated operation including central air-conditioning, maximizing the reduction in air-conditioning and heating energy consumption [39], as shown in Table 10.
• Shanghai World Expo Theme Pavilion, Shanghai, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 100%, and the EPI index is 22, which indicates that the building energy efficiency index of this scheme is high, and it reaches the standard of zero energy building evaluated by CABEE. At the same time, the program has the following design and energy-saving highlights. Firstly, the roof shape is tilted to better adapt to the photovoltaic solar panels, and the roof lighting skylight is combined into the roof texture, with an area of 30,000 square meters of solar panels with a total power generation capacity of 2.8 megawatts, which reduces CO₂ emissions by about 2500 tonnes per year, and it takes the lead in exploring the domestic practice of applying large-scale photovoltaic building integration. Secondly, in line with the concept of energy saving and environmental protection advocated by the World Expo, the building façade introduces a vertical green wall system, whose supporting keel echoes the rhombic texture of the roof, which improves the urban heat island effect and reduces the indoor temperature and the urban drainage load through the matching of different plants. Third, a variety of photovoltaic building-integrated modules are used. Roof-integrated modules and large-area light-transmitting photovoltaic panels are used [47], as shown in Table 10.
• Xiuzhou Photovoltaic Technology Exhibition Hall, Jiaxing, Zhejiang, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 100%, and the EPI index is 43, which indicates that the building energy efficiency index of this scheme is high. This indicates that the program has a high energy efficiency index and meets the standard of zero energy building as assessed by CABEE. At the same time, the scheme has the following design and energy-saving highlights. Firstly, 5000 square meters of CdTe photovoltaic thin-film glass and 600 square meters of crystalline silicon photovoltaic panels are used on the façade and roof of the pavilion, which allow for both light harvesting and power generation. Secondly, the pavilion also adopts energy-saving and environmentally friendly building materials, and the air-conditioning inside the pavilion adopts the clean and environmentally friendly ground-source heat pump air-conditioning system to achieve energy saving and emission reduction. Thirdly, a variety of photovoltaic building integration modules are used, with a total solar power generation power of about 400 KWp, making it a benchmark project for photovoltaic building integration in China [52], as shown in Table 10.
• Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation, Beijing, China. Through the systematic formula calculation, it can be seen that the energy balance of this case reaches 100%, and the EPI index is 21, indicating that the building has a high energy efficiency index, which meets the standard of zero energy building evaluated by CABEE. The energy balance of the project reaches 100% and the EPI index is 21, which indicates that the building energy efficiency index of the project is high, and it reaches the standard for a zero energy building assessed by CABEE. The solution adopts photovoltaic power generation technology, which not only can use the sunlight on the surface of the building to generate electricity but also can effectively reduce the indoor solar radiation to achieve the cooling effect, thus saving the energy consumption of building cooling. Secondly, the original LOW-E glass is replaced with BIPV components and high transmittance, low-emissivity double-silver-coated glass to achieve a more efficient building solution. This reduces heat loss and ensures a comfortable indoor environment. Thirdly, the combination of PV modules with an integrated system of building construction materials effectively improves the thermal insulation and heat preservation performance of the building, thus further reducing the energy consumption for cooling and heating of the building [54], as shown in Table 10.

5.2. Analytical Map of GAT Assessment of Classical BIPV in the Context of nZECB in China

Based on the “Evaluation Criteria for Solar Photovoltaic Building Application Systems” published globally by China Association for Building Energy Efficiency (CABEE) in 2013 and the “Technical Standard for Application of Building Photovoltaic Systems GB/T 51368-2019” published globally by China Architecture & Building Press in 2019, the current status of the evaluation of the classic BIPV cases in the context of China’s nZECB is presented in a visual way [60] in

Table 11. Analytical map of GAT assessment of classical BIPV in the context of nZECB in China.

		Criteria
Case Study	Dimension	Extent	Coherence	Flexibility	Intensity
Haixi Solar Photovoltaic Exhibition Hall, Qinghai, China	BIPV Applicable Performance Evaluation
	BIPV Safety Performance Evaluation	(+)
	BIPV Durability Performance Evaluation			(+)
	BIPV Economic Performance Evaluation
	BIPV Operation and Maintenance Evaluation	(+)			(+)
Shenzhen Dameisha Vanke Center, Shenzhen, China	BIPV Applicable Performance Evaluation
	BIPV Safety Performance Evaluation
	BIPV Durability Performance Evaluation			(+)
	BIPV Economic Performance Evaluation		(+)
	BIPV Operation and Maintenance Evaluation	(+)		(+)	(+)
Datong Future Energy Museum, Shanxi, China	BIPV Applicable Performance Evaluation				(+)
	BIPV Safety Performance Evaluation		(+)
	BIPV Durability Performance Evaluation
	BIPV Economic Performance Evaluation	(+)	(+)
	BIPV Operation and Maintenance Evaluation			(+)	(+)
Shanghai World Expo Theme Pavilion, Shanghai, China	BIPV Applicable Performance Evaluation	(+)
	BIPV Safety Performance Evaluation		(−)	(+)
	BIPV Durability Performance Evaluation
	BIPV Economic Performance Evaluation
	BIPV Operation and Maintenance Evaluation	(+)	(+)
Xiuzhou Photovoltaic Technology Exhibition Hall, Jiaxing, Zhejiang, China	BIPV Applicable Performance Evaluation
	BIPV Safety Performance Evaluation			(+)
	BIPV Durability Performance Evaluation	(−)			(+)
	BIPV Economic Performance Evaluation	(+)		(+)
	BIPV Operation and Maintenance Evaluation
State Power Investment Corporation Headquarters Building, Beijing, China	BIPV Applicable Performance Evaluation		(−)
	BIPV Safety Performance Evaluation				(+)
	BIPV Durability Performance Evaluation
	BIPV Economic Performance Evaluation		(+)		(+)
	BIPV Operation and Maintenance Evaluation		(+)

Colors red: poor; orange: medium; green: good.

(in the form of a “Gat Scorecard”). The green cells represent the results of the analyzed problems according to the short matrix of GAT problems. These results are considered satisfactory (positive)—on the contrary, the results for the red cells are considered worrying (negative) and the results for the orange cells are considered rather unsatisfactory or uncertain (neutral). A (+) indicates that the current situation is changing in a positive direction or will change positively in the foreseeable future, while a (−) indicates that the situation is deteriorating and is unlikely to improve in the foreseeable future [61], as shown in Table 11.

5.3. BIPV Applicable Performance Evaluation

An essential key link in the development of solar photovoltaic technology is the production of electricity using BIPV. Dust, exhaust pollution, and noise are not present while power is being generated. It can absorb the light reflected by solar energy on the glass surface and lessen light pollution by using new materials and technology [62]. Buildings can be used wisely to conserve land resources, and solar photovoltaic power generation can not only ensure self-sufficiency but also help protect the environment by supplying additional power to the urban power grid, which satisfies the demands of energy conservation and environmental protection [63].

At the same time, the photovoltaic system should have certain regulation capabilities, including active regulation, reactive power regulation, energy storage, load prediction, etc. In order to adapt to a high proportion of photovoltaic access conditions and reverse power flow to ensure the safe and reliable operation of the distribution network, the photovoltaic system’s integrated power generation efficiency reaches higher than 80% [60]. The evaluation results of the Haixi Solar Photovoltaic Exhibition Hall, Datong Future Energy Museum, and Xiuzhou Photovoltaic Technology Exhibition Hall in this section are good, and the relevant indicators perform well [64], as shown in Table 11.

5.4. BIPV Safety Performance Evaluation

The most outside structural design in architectural engineering is BIPV [65]. Glass panels and metal frames with BIPV make up the majority of solar curtain walls used in practical applications. The integration of solar modules and glass curtain walls results in BIPV. There are also strict standards for the strength of solar curtain walls in order to guarantee the smooth progression of photovoltaic transformation. As a result, we must choose a type for the construction that is reasonable given the circumstances. The choice of BIPV must take into account the building’s individual characteristics, taking into account details like the building’s height, elevation, construction style, and other aspects that can be identified by precise calculation [66].

At the same time, the PV combiner box is located for easy operation and maintenance. The IP protection level of the outdoor PV converter box is higher than the requirement of IP65. The withstand voltage of the internal wiring and the lightning arrester configured in the box is not less than two times the maximum system voltage of the PV system. The evaluation results of the Shenzhen Dameisha Vanke Center and Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation in this section are good, and the relevant indicators perform well [60], as shown in Table 11.

5.5. BIPV Durability Performance Evaluation

The construction of solar curtain walls is comparable to that of traditional curtain walls and has the advantages of a longer service life, which may effectively guarantee the structural service life of BIPV. China currently possesses the largest solar cell array and maximum power tracking (MPPT) system in the world [67]. The emergence of new materials and technologies also makes the service life of photovoltaic modules longer and longer [59].

At the same time, the photovoltaic curtain wall or photovoltaic light roof meets the relevant requirements of GB29551 and the national standard “Solar Photovoltaic Insulating Glass for Architecture” [2]. For photovoltaic modules used in high-temperature and high-humidity areas, qualified products that can pass the high-temperature and high-humidity aging test at a temperature of 85 degrees Celsius, a humidity of 85% RH, and a time of not less than 2000 h are used. The evaluation results of the Datong Future Energy Museum and Shanghai World Expo Theme Pavilion cases in this section are good, and the relevant indicators perform well, as shown in Table 11.

5.6. BIPV Economic Performance Evaluation

In traditional BIPV, photovoltaic modules are generally installed in glass curtain wall components, which can not only protect the appearance of the curtain wall from being affected but also maintain the normal operation of photovoltaic modules and avoid the environmental impact of the external environment (wind load, rain, etc.) on photovoltaic modules [66]. Firstly, compared with BAPV, BIPV can save PV installation costs, building material costs, subsequent PV module maintenance, etc., as well as improve the aesthetic appearance of the building. As most of the policy is combined with green building, with the landing of BIPV and subsidy policy for green building evaluation qualified, the relevant departments provide square meter subsidy price support. At the same time, the system’s electrical efficiency of the PV module DC output to the inverter output is higher than 95%. According to the theoretical full-year power generation of the PV system and local electricity price, the static payback period of the PV system is no more than 6 years [68]. Secondly, the PV system should be integrated with site conditions, building functions, the surrounding environment and other factors, and it should reasonably determine the building mix and spatial environment, etc., under the premise of conforming to the relevant design and installation norms, and it should also comprehensively consider the comprehensive utilization of other renewable energy sources, such as solar water heating systems [69]. The evaluation results of the Haixi Solar Photovoltaic Exhibition Hall and Shanghai World Expo Theme Pavilion in this section are good, and the relevant indicators perform well, as shown in Table 11.

5.7. BIPV Operation and Maintenance Evaluation

Due to the small area of solar panels, a large inclination layout is adopted, which can ensure daylight and does not affect beauty. At the same time, it also has good thermal insulation effect and fire resistance [60]. At present, a large number of large, medium and small curtain wall components have come out in China, and the installation technology of curtain walls has been quite mature [61], which can fully realize the convenience of construction [64]. The light transmittance of photovoltaic modules has advanced due to the rapid advancement of photoelectric technology, and as a result, it is no longer difficult for BIPV systems to meet lighting needs. Additionally, BIPV systems can complete the refined management of indoor solar light intensity under the condition of providing effective lighting [65].

More often than not, special operation and maintenance programs have been developed for the use of PV systems in areas with salt spray, cold and snow. Subsequently, the relevant departments have appropriate after-sales maintenance departments, personnel and corresponding management systems, and they can remotely monitor the operation of the PV system. Secondly, the relevant departments should carry out regular inspections of the PV system during the warranty period. In this section, the evaluation results of the above cases of Xiuzhou Photovoltaic Technology Exhibition Hall and Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation are good, and the relevant indicators perform well [70], as shown in Table 11.

In summary, based on the above analytical map of GAT assessment of classical BIPV in the context of nZECB in China, a systematic assessment was carried out using a quantitative form of the table, as shown in Table 11.

6. Challenge

In the context of carbon neutrality, there are two ways to achieve zero energy consumption buildings. One is energy saving, that is, the building itself and its use should achieve low energy consumption. The current technology in the field of building energy consumption is relatively mature, and countries have also gradually developed it [71], corresponding to specification requirements. Therefore, it can be said that building energy conservation is an inevitable problem in the future development, which requires us to conduct in-depth research on it and find solutions. From the perspective of photovoltaic power generation technology, it is necessary to make full use of building-integrated photovoltaic technology to make the building itself have the power generation function, make full use of the building surface, and consider the selection of power generation building materials and the overall system design according to the building structure and function design without affecting the use [48]. The realization of zero energy consumption and even the negative energy consumption of buildings is an important feature of new buildings, and it is an important way to achieve zero energy consumption with new energy as the main source in the reform of the power structure [51]. However, there are still many problems and challenges with China’s comprehensive implementation of zero energy consumption buildings, which also exist in European and American countries.

6.1. Unbalanced and Insufficient Matching between New Energy Power Generation and Actual Energy Consumption of Buildings

Based on the current high energy consumption of buildings and the current status of photovoltaic technology, most of the time, it is difficult to fully meet the energy supply of building energy consumption [52]. Therefore, solving building energy consumption requires an equal emphasis on increasing revenue and reducing expenditure. On the one hand, we should continue to improve the application of building energy-saving-related technologies. In order to reduce the actual energy consumption of the building and use the DC power supply mode to improve the energy supply’s efficiency, power-generating building materials are widely used in building envelopes to reduce the energy consumed by the building itself [65]. On the other hand, it is necessary to strengthen the maintenance of existing buildings to extend their service life. There are many ways to realize the energy supply of the building itself. Therefore, as far as the current situation of excessive building energy consumption in contemporary China is concerned, it is due to the imbalance between building energy creation and building energy consumption [72]. In the future, energy storage and comprehensive energy management technologies must be used to optimize management, improve energy utilization efficiency and energy supply stability, and realize the energy supply problem of the building itself [57].

6.2. Integration of Power Generation Capacity and Architectural Aesthetics Technology, Structural Safety, and Thermal Insulation When Power-Generating Building Materials Are Combined with Buildings

Solar power generation technology has been widely promoted and applied. There are many cases of the installation and application of photovoltaic power generation technology in buildings, all of which can sufficiently solve the problem of combining power generation building materials with buildings in use in ways that are in line with architectural aesthetics and structure. Projects with safety requirements are still rare [45]. Building decoration engineering refers to the main components in the building, which directly affects the use efficiency and quality of the building. In recent years, due to various factors, there have been many major safety accidents in China’s building materials industry, which have resulted in serious casualties and losses. At the same time, with the development of the social economy, energy shortage has become one of the important restrictive factors for human survival and development, and the use of clean and renewable energy is the most effective way to alleviate this contradiction. Therefore, the application of power-generating building materials in architectural design needs to be carried out at the same time [31]. It is necessary to consider both the aesthetic requirements of building energy consumption for building perimeter protection and the improvement of power-generating building materials’ power generation capacity.

6.3. There Are Problems in the Relevant Standards of Power Generation Building Materials and Building-Integrated Photovoltaic Application Technology

For zero energy consumption buildings, the main method is to realize the utilization of power-generating building materials [62]. However, at present, the power-generating materials on the market in many countries still use “power generation” as the main method. The function of building materials is not outstanding, and “two skins” are still generally used in the use process. One of the reasons is that the power generation function is integrated with the building material function. There are still many technologies that have not substantially broken through the limitations [73]. The current regulations related to building-integrated photovoltaics are aimed at photovoltaics.

7. Discussion and Hypothesis

7.1. Innovative Approaches toward BIPV in China

China’s progress in the field of urban construction during the “13th Five-Year Plan” period has achieved remarkable results. The government has adopted a series of measures such as top-level design, mechanism construction, scientific research guarantee, policy and norm formulation, etc., to strongly promote the development of ultra-low energy. With the acceleration of China’s urbanization process and the improvement of people’s living standards [55], as well as the increasingly stringent requirements for energy conservation and emission reduction, ultra-low energy buildings are also facing some problems and challenges in the process of rapid promotion and application [36].

In order to further accelerate the promotion and application of ultra-low energy buildings, the National Development and Reform Commission recently issued the Notice on Carrying out the Pilot Demonstration of Energy-Efficiency Labeling for Public Buildings, suggesting that the pilot work of energy-efficiency labeling of public buildings be organized nationwide. As of June 2020, a total of 47 policies and measures have been formulated in 10 provinces, autonomous regions and 17 cities across the country, and specific incentive measures or development plans have been proposed for ultra-low energy construction [74].

According to data from the “14th Five-Year Plan” photovoltaic power generation forecast report by Ren Yuzhi, deputy director of the New Energy Department of the China Energy Administration, at the 2020 China Photovoltaic Industry Annual Conference, it is expected that during China’s “14th Five-Year Plan” period, PV will add about 400 GW, which is more than 100% year-on-year growth rate compared with the “13th Five-Year Plan”, reaching the “doubling” stage. The cumulative installed capacity increased from 253 to 650 GW, including about 440 GW of ground power stations and about 210 GW of distributed projects [75], as shown in Figure 6. Regarding how to better popularize BIPV in China, the specific target suggestions are as follows:

In terms of policy support, China proposed many policies on BIPV energy-saving buildings during the “Fourteenth Five Year Plan”. Although the national electricity subsidy for industrial and commercial distributed photovoltaics has been cancelled [75], the BIPV project is still given preferential treatment by the national and local governments for green buildings. As shown in Table 11, it is China’s incentive policy for BIPV projects in recent years. After a number of policies were issued, various provinces and cities successively introduced policies for the demonstration and promotion of ultra-low energy consumption buildings [36], and they put forward policy preferences in terms of financial subsidies, non-capacity area incentives, record price rises, green credit, etc.

Next, we summarize the existing incentive measures of China, which are equally applicable and beneficial to Europe and the United States, and consider the following incentive measures and suggestions:

• Most of them are subsidized according to the area or power generation of photovoltaic projects. It includes different construction categories of roof photovoltaic projects, facade building-integrated photovoltaic projects, charging infrastructure projects, public building facilities projects and residential projects [42]. Most of them are subsidized according to the local government, and some have signed contracts with enterprises to reduce the cumbersome operation of management mode.
• Many local governments will also choose to reduce taxes to encourage usage. The government will give tax reduction subsidies corresponding to the total area of enterprises’ office buildings, factory buildings, shantytowns and other places where solar energy is laid [76].
• Subsidies for scientific research and development. The government also has a number of subsidies for solar photovoltaic entrepreneurship, company expansion, production line expansion, etc., which will be given according to the definition of invention capacity.
• In addition, some regions will evaluate whether the building is suitable for the installation of photovoltaic equipment and mandatory installation. In addition, the star rating of environmental protection will be conducted according to the commercial and working properties of the building. Buildings with different star level standards will have different subsidy standards [53].
• Encourage residents to renovate their houses. Evaluate the residential buildings suitable for reconstruction, evaluate the commercial and environmental protection value, and then choose cooperative management subsidies, a one-time single subsidy or area subsidy, and accurately implement the “One appropriate subsidy for each family”. Enterprises can choose to transform for the masses for free and then distribute the income of solar power generation in a certain proportion.
• Give subsidies to enterprises or residents for publicity and promotion. If the enterprise actively implements and publicizes the laying of photovoltaic projects, there will be additional financial subsidies, research and development subsidies or tax reduction subsidies, and they even can evaluate the demonstration of green building construction cases and give one-time subsidies. Residents can also receive gifts or subsidies according to the number of users [45], area and other reference standards promoted by themselves.

7.2. Strategies and Solutions for BIPV Optimization

With the comprehensive implementation of the Paris Agreement, the pursuit of carbon neutrality has emerged as a focal point of international discourse. An increasing number of economies are articulating ambitious carbon neutrality targets, ushering in an era of amplified international efforts in this arena. Consequently, within the global construction domain, the linchpin of achieving the “carbon neutrality” objective will undoubtedly hinge upon energy conservation and carbon reduction [67]. As urbanization continues to burgeon, confronting substantial market dynamics and developmental contexts, the strategic implementation of standardization stands poised to catalyze the transformation and elevation of the construction industry. This paradigm shift is poised to yield significant contributions to industry innovation and growth, fostering advancements in technology and market conditions, ultimately culminating in a harmonious synergy between humankind and nature [75].

Drawing from the data analysis of seminal building-integrated photovoltaic (BIPV) cases in China as elucidated in the preceding sections, and mindful of the array of factors influencing BIPV performance and the challenges confronting the realization of zero energy consumption objectives, the ensuing resolution to elevate clean energy efficacy and holistically optimize BIPV objectives is articulated. These strategies hold applicability in contemporary China as well as across European and American contexts:

• Proactively cultivate the leadership role of modernized standards within the construction realm. Tailored to the urban construction level in diverse nations, the propagation of modern technical benchmarks within the construction industry should be propelled, harnessing the market’s pivotal role in allocating technical resources. This symbiotic cultivation of innovation and norm establishment, bolstered by product inspection, will foster a burgeoning culture of recommended norms [62]. A seamless fusion of production, education, and research will be underpinned, with emphasis on strengthening standards through dedicated research, expediting the establishment of adaptive technical standards, and cementing a sustainable mechanism for standardized governance.
• Pioneering the NGI “Opinions” necessitates rigorous exploration and the formulation of obligatory policy measures and associated specifications. This entails a nuanced delineation of phased construction indices and pivotal construction facets. Key technologies encompassing the realm of construction’s thermal attributes, electromechanical control systems, fresh air management, and intelligent control are earmarked for rigorous technology formulation, energy criteria, and evaluative standards [60]. For new buildings, the report proposes that people’s governments at all levels should formulate relevant preferential policies and incentive measures as well as formulate more standardized energy-saving technical standards to significantly reduce the energy intensity of heating, cooling, ventilation, door-to-window ratio, envelope and lighting in the field of new building construction [54].
• Spearheading the pursuit of technical emission reduction channels and avenues, the inquiry delves into innovative strategies for curbing carbon emissions in the burgeoning construction sector. Parallelly, fortifying the investigation and application of energy-saving technologies for new constructions is advocated. Meanwhile, extirpating outdated production capacities and advancing industrial metamorphosis and upgrading remains pivotal. Embracing the rejuvenation and recycling of extant public edifices, coupled with measures spanning financing assurances, tax incentives, and eco-friendly services, aims to augment new building energy management paradigms [61].
• Charting a path for the propagation of carbon labeling, this endeavor is underpinned by concerted efforts in raising awareness, offering guidance, and facilitating information exchange regarding building energy conservation, green structures, and cutting-edge low-carbon technologies. By orchestrating standard publicity, training, and low-carbon awareness initiatives, a government-fostered promotional model, with active enterprise participation, is envisaged. To culminate, actionable policy recommendations are postulated, which are grounded in a multifaceted understanding of various nations: bolster the legal and regulatory infrastructure, mandating national standards; amplify energy conservation and emission reduction advocacy, heightening the nation’s consciousness about energy and environmental preservation [39]. Augmented support for enterprise energy conservation and emission reduction measures should be erected. Aspiring nations are urged to draw insights from trailblazing developed countries such as the United Kingdom and Japan, pioneering voluntary product carbon labeling management frameworks. Consequently, governments ought to institute analogous product carbon labeling systems to progressively elevate consumer cognizance of carbon management, concretizing a more comprehensive social and ecological milieu.
• The optimization of building envelope components like building physics, shading, glass, ventilation, and orientation remains imperative. Lighting, insulation, and load reduction emerge as pivotal elements to ameliorate building energy efficiency, with strategies such as enhanced insulation thickness, augmented airtightness, and external shading devices emerging as potent strategies to mitigate energy demand [75], increase solar gain, reduce the need for heating in winter, etc.
• Contextual recognition of regional and climatic factors is crucial to maximally harness their potential, enabling energy efficiency, heat, and electricity load computations. Simulation software plays a pivotal role in simulating annual heating and cooling demands as well as integrating localized climatic nuances into comprehensive building element considerations prior to construction. Recognizing the variances stemming from climatic diversity, the study underscores differential impacts across distinct components [76].

8. Conclusions and Prospect

This study elaborates the theoretical basis of zero energy buildings and BIPV as well as the current status of the construction of the world’s low-carbon building standard system, and it summarizes the annual electricity generation of zero carbon buildings adopting BIPV in some European countries. Then, the article further quantitatively and comprehensively analyzes six successful BIPV application cases in China, which are the Haixi Solar Photovoltaic Exhibition Hall, Shenzhen Dameisha Vanke Center, Datong Future Energy Museum, Shanghai World Expo Theme Pavilion, Xiuzhou Photovoltaic Technology Exhibition Hall and Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation. Using the EPI evaluation and measurement tool, a graphical visual assessment and presentation of the annual average net zero energy performance percentage of the application cases was made. Based on the results of this assessment, the challenges of BIPV development in China are summarized, and specific incentives for new BIPVs and strategic approaches to optimizing BIPVs are proposed to address the challenges, leading to the following conclusions:

• The six classic BIPV cases in China, as measured by the EPI formula and evaluated by the GAT visualization table, yielded relevant net-zero energy indicators showing that the six classic cases basically achieved 100% net-zero energy operation and maintenance, greatly reducing CO₂ emissions and saving tens of thousands of tonnes of coal consumption, like the Xiuzhou Photovoltaic Technology Exhibition Hall and Smart Energy Demonstration Project for the Headquarters Building of the State Power Investment Corporation. In both cases, while the buildings themselves achieve net-zero annual energy consumption, there is also a large amount of solar clean power energy left over for storage or for sale online to the relevant units, bringing additional economic benefits.
• This shows that BIPV technology is gradually maturing in China and the production supply chain is improving, and the cost of large-scale deployment will be reduced. In the future, more residential and rural distributed PV system applications will be carried out in China’s prefectural cities, townships and rural areas.
• This indicates that with the improvement and increase in green building incentives and preferential subsidies given to BIPV projects by the governments of various provinces and prefectural cities in China, there is a great deal of advantage and room for incremental development in the promotion of BIPV in China, which will gradually become highly integrated into the relevant downstream markets.
• Analysis shows that by fully identifying and applying the advantages of China’s diverse regional topography and rich climatic factors, the benefits of different regions and climatic factors can be maximized, and simulation software can be used at the design stage to simulate the energy efficiency, thermal and electrical load calculations, and the annual heating and cooling demand, so as to achieve the maximum and optimal net-zero energy O&M of BIPV in accordance with local conditions.
• Analysis shows that crystalline silicon cells occupy more than 95% of the market share in the photovoltaic industry by virtue of the advantages of economy and conversion efficiency. The conversion efficiency of monocrystalline silicon solar cells is mostly between 18% and 25%. Combined with China’s various natural conditions and practical basis, China’s future large scale in the implementation of BIPV development in the case of selecting a 290 Wp monocrystalline silicon photovoltaic-type module is the most appropriate, and its cost and the average annual return are theoretically the most considerable.
• Its BIPV optimization strategy and methodology is highly suitable for application and promotion strategies in China, and it is equally applicable to Europe and the United States, as well as the rest of the world, to the extent that a more efficient and higher-quality implementation of the “carbon neutral” strategy and the zero net energy consumption development will achieve a greener and cleaner future.

The future large-scale application of zero energy building design and BIPV will also be a key step in reducing low energy consumption and carbon emissions. Although a great deal of research has been conducted in this area, there is still room for improvement through further insights into the following technology extensions and incentives. The next steps in the research program and the outlook for tomorrow are set out below.

• The next step of the study will be to further investigate more classic BIPV cases in China and to analyze and summarize the net cooling energy consumption index and green technology operation and maintenance in more depth by increasing the base sample.
• From the current regional climate distribution of BIPV in China, there are still a few practical cases of BIPV application and research in temperate monsoon climatic regions in China. The next step of the study will be to encourage the development of practical case applications in this climate zone, with corresponding experimental and numerical research work.
• The next step in the research program will also focus on practical examples of BIPV in various regions and climatic zones throughout China, how to carry out subsequent management, maintenance and upkeep more sustainably, and how to form a number of low-cost solutions for sustainable operation and maintenance in different regions, with a particular focus on the use of photovoltaic systems with special operation and maintenance schedules in areas with salt spray, cold and snowfall.
• Building-integrated photovoltaic (BIPV) systems can contribute to the carbon neutral development process, low carbon green development, clean energy promotion, climate change, etc., and in future BIPV research and applications, researchers can analyze how to maximize the benefits of clean energy conversion in buildings.