Energies

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18 pages, 2052 KiB

Open AccessArticle

Allocation of Ontario’s Surplus Electricity to Different Power-to-Gas Applications

by Suaad S. Al-Zakwani, Azadeh Maroufmashat, Abdelkader Mazouz, Michael Fowler and Ali Elkamel

Energies 2019, 12(14), 2675; https://doi.org/10.3390/en12142675 - 12 Jul 2019

Cited by 9 | Viewed by 3353

Abstract

Power-to-Gas (PtG) is a potential means of managing intermittent and weather-dependent renewable energies to create a storable chemical energy form. Power-to-Gas is not only a storage technology; its role can be extended to many other applications including energy distribution, transportation, and industrial use. [...] Read more.

Power-to-Gas (PtG) is a potential means of managing intermittent and weather-dependent renewable energies to create a storable chemical energy form. Power-to-Gas is not only a storage technology; its role can be extended to many other applications including energy distribution, transportation, and industrial use. This study quantifies the hydrogen volumes upon utilizing Ontario, Canada’s surplus electricity baseload and explores the allocation of the hydrogen produced to four Power-to-Gas pathways in terms of economic and environmental benefits, focusing on the following Power-to-Gas pathways: Power-to-Gas to mobility fuel, Power-to-Gas to industry, Power-to-Gas to natural gas pipelines for use as hydrogen-enriched natural gas, and Power-to-Gas to renewable natural gas (i.e., Methanation). The study shows that the Power-to-Gas to mobility fuel pathway has the potential to be implemented. Utilization of hydrogen for refueling light-duty vehicles is a profitable business case with an average positive net present value of $4.5 billions, five years payback time, and 20% internal rate of return. Moreover, this PtG pathway promises a potential 2,215,916 tonnes of CO₂ reduction from road travel. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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19 pages, 2676 KiB

Open AccessArticle

Assessment of an Innovative Way to Store Hydrogen in Vehicles

by Andresa Baptista, Carlos Pinho, Gustavo Pinto, Leonardo Ribeiro, Joaquim Monteiro and Tiago Santos

Energies 2019, 12(9), 1762; https://doi.org/10.3390/en12091762 - 9 May 2019

Cited by 9 | Viewed by 3712

Abstract

The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However, due to its physical characteristics, storage is still a challenge. There is an innovative way, presented in this study, to store hydrogen in conventional vehicles [...] Read more.

The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However, due to its physical characteristics, storage is still a challenge. There is an innovative way, presented in this study, to store hydrogen in conventional vehicles propelled by spark-ignition reciprocating engines and fuel cells, using hydrogen as fuel; the storage of hydrogen will be at high pressure within small spheres randomly packed in a tank, like the conventional tank of fuel used nowadays in current vehicles. Therefore, the main purpose of the present study is to assess the performance of this storage system and compare it to others already applied by car manufacturers in their cars. In order to evaluate the performance of this storage system, some parameters were taken into account: The energy stored by volume and stored by weight, hydrogen leakage, and compliance with current standards. This system is safer than conventional storage systems since hydrogen is stored inside small spheres containing small amounts of hydrogen. Besides, its gravimetric energy density (GED) is threefold and the volumetric energy density (VED) is about half when compared with homologous values for conventional systems, and both exceed the targets set by the U.S. Department of Energy. Regarding the leakage of hydrogen, it complies with the European Standards, provided a suitable choice of materials and dimensions is made. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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15 pages, 3595 KiB

Open AccessArticle

Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance

by Elia Judith Martínez, Ana Sotres, Cristián B. Arenas, Daniel Blanco, Olegario Martínez and Xiomar Gómez

Energies 2019, 12(7), 1228; https://doi.org/10.3390/en12071228 - 30 Mar 2019

Cited by 39 | Viewed by 5776

Abstract

The effect of hydrogen pulse addition on digestion performance of sewage sludge was evaluated as a means for studying the increase in efficiency of methane production. Microbial communities were also evaluated to get an insight of the changes caused by the operational modifications [...] Read more.

The effect of hydrogen pulse addition on digestion performance of sewage sludge was evaluated as a means for studying the increase in efficiency of methane production. Microbial communities were also evaluated to get an insight of the changes caused by the operational modifications of the digester. An energy evaluation of this alternative was performed considering the theoretical process of coupling bioelectrochemical systems (BES) for the treatment of wastewater along with hydrogen production and the subsequent anaerobic digestion. The addition of hydrogen to sewage sludge digestion resulted in an increase of 12% in biogas production over the control (1353 mL CH₄ d⁻¹ at an injection flow rate of 1938 mL H₂ d⁻¹). The liquid phase of the sludge reactor and the H₂ supplemented one did not show significant differences, thus indicating that the application of hydrogen as the co-substrate was not detrimental. High-throughput sequencing analysis showed slight changes in archaeal relative abundance after hydrogen addition, whereas eubacterial community structure and composition revealed noteworthy shifts. The mass and energy balance indicated that the amount of hydrogen obtained from a hypothetical BES can be assimilated in the sludge digester, improving biogas production, but this configuration was not capable of covering all energy needs under the proposed scenario. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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14 pages, 1562 KiB

Open AccessArticle

Numerical Simulation and Experimental Investigation of Diesel Fuel Reforming over a Pt/CeO₂-Al₂O₃ Catalyst

by Hanyu Chen, Xi Wang, Zhixiang Pan and Hongming Xu

Energies 2019, 12(6), 1056; https://doi.org/10.3390/en12061056 - 19 Mar 2019

Cited by 9 | Viewed by 2976

Abstract

In order to benefit from a realistic hydrogen production device equipped on a vehicle, issues with the effects of the process parameters on H₂ and CO yield need to be resolved. In this study, a reduced mechanism for n-heptane (as a [...] Read more.

In order to benefit from a realistic hydrogen production device equipped on a vehicle, issues with the effects of the process parameters on H₂ and CO yield need to be resolved. In this study, a reduced mechanism for n-heptane (as a surrogate diesel) reforming over a Pt/CeO₂-Al₂O₃ catalyst is adopted to investigate the effects of the process parameters on H₂ and CO yield, and the preferred process parameters are concluded. In addition, the comparison of reforming bench tests of diesel fuel and n-heptane under typical diesel engine operating conditions is conducted. The n-heptane reforming simulation results show that the maximum H₂ and CO yield moves toward unity with the decreased GHSV and increased reaction temperature, and the GHSV of 10,000 1/h, O₂/C ratio of 0.6 and reaction temperature of 500 °C is preferable. The contrast experiments reveal that the change trend of H₂ and CO yield displays consistence, although the difference of the average H₂ and CO yield results is obvious. The characteristics of n-heptane reforming can represent H₂ and CO yield features of diesel fuel reforming at typical reaction temperatures in a way. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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10 pages, 1119 KiB

Open AccessArticle

Effect of Hydrogen Refueling Parameters on Final State of Charge

by Jinsheng Xiao, Shuo Ma, Xu Wang, Shanshan Deng, Tianqi Yang and Pierre Bénard

Energies 2019, 12(4), 645; https://doi.org/10.3390/en12040645 - 17 Feb 2019

Cited by 15 | Viewed by 3343

Abstract

The state of charge (SOC) is a key indicator to show whether a compressed hydrogen tank meets refueling requirements, so it is worth to study effects of the refueling parameters on it. A new SOC analytical solution is obtained based on a simple [...] Read more.

The state of charge (SOC) is a key indicator to show whether a compressed hydrogen tank meets refueling requirements, so it is worth to study effects of the refueling parameters on it. A new SOC analytical solution is obtained based on a simple thermodynamic model. By applying a mass balance equation and an energy balance equation for a hydrogen storage system, a differential equation was obtained. An analytical solution of hydrogen temperature was deduced from the solution of the differential equation, then an analytical solution of hydrogen mass was further deduced based on the analytical solution of hydrogen temperature with some mathematical modifications. By assuming the hydrogen density inside the tank is uniform, the SOC, which defined as a ratio of hydrogen density to the full-fill density, can be transformed to be the ratio of hydrogen mass to the full-fill mass. The hydrogen mass can be calculated from analytical solution of hydrogen mass, while the full-fill mass is supposed to be a constant value. The full-fill density of 35 MPa and 70 MPa tanks at 15 °C are respectively 24.0 g/L and 40.2 g/L, and if the volume of the tank is known, the full-fill mass can also be calculated. The analytical solution of SOC can be unitized to express the reference data, the contributions of inflow temperature and mass flow rate on SOC are presented for a Dynetek type III tank (40 L, metallic liner) and a Hexagon type IV tank (29 L, plastic liner). In addition, the two-parameter effect of inflow temperature and mass flow rate on SOC are presented. The Nusselt number and Reynolds number are utilized to modify the analytical model, the relationship between SOC and refueling parameters can be obtained through the method of fitting. The fittings show a good agreement. The SOC can be determined from the refueling parameters based on the model with more physical meaning. The method developed in this research can be applied to the control algorithm of refueling stations to ensure safety and efficiency. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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10 pages, 2534 KiB

Open AccessArticle

On-Board Cold Thermal Energy Storage System for Hydrogen Fueling Process

by Young Min Kim, Dong Gil Shin and Chang Gi Kim

Energies 2019, 12(3), 561; https://doi.org/10.3390/en12030561 - 12 Feb 2019

Cited by 9 | Viewed by 4315

Abstract

The hydrogen storage pressure in fuel cell vehicles has been increased from 35 MPa to 70 MPa in order to accommodate longer driving range. On the downside, such pressure increase results in significant temperature rise inside the hydrogen tank during fast filling at [...] Read more.

The hydrogen storage pressure in fuel cell vehicles has been increased from 35 MPa to 70 MPa in order to accommodate longer driving range. On the downside, such pressure increase results in significant temperature rise inside the hydrogen tank during fast filling at a fueling station, which may pose safety issues. Installation of a chiller often mitigates this concern because it cools the hydrogen gas before its deposition into the tank. To address both the energy efficiency improvement and safety concerns, this paper proposed an on-board cold thermal energy storage (CTES) system, cooled by expanded hydrogen. During the driving cycle, the proposed system uses an expander, instead of a pressure regulator, to generate additional power and cold hydrogen gas. Moreover, CTES is equipped with phase change materials (PCM) to recover the cold energy of the expanded hydrogen gas, which is later used in the next filling to cool the high-pressure hydrogen gas from the fueling station. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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16 pages, 1908 KiB

Open AccessArticle

Use of Hydrogen in Off-Grid Locations, a Techno-Economic Assessment

by Lorién Gracia, Pedro Casero, Cyril Bourasseau and Alexandre Chabert

Energies 2018, 11(11), 3141; https://doi.org/10.3390/en11113141 - 13 Nov 2018

Cited by 51 | Viewed by 7426

Abstract

Diesel generators are currently used as an off-grid solution for backup power, but this causes CO₂ and GHG emissions, noise emissions, and the negative effects of the volatile diesel market influencing operating costs. Green hydrogen production, by means of water electrolysis, has [...] Read more.

Diesel generators are currently used as an off-grid solution for backup power, but this causes CO₂ and GHG emissions, noise emissions, and the negative effects of the volatile diesel market influencing operating costs. Green hydrogen production, by means of water electrolysis, has been proposed as a feasible solution to fill the gaps between demand and production, the main handicaps of using exclusively renewable energy in isolated applications. This manuscript presents a business case of an off-grid hydrogen production by electrolysis applied to the electrification of isolated sites. This study is part of the European Ely4off project (n° 700359). Under certain techno-economic hypothesis, four different system configurations supplied exclusively by photovoltaic are compared to find the optimal Levelized Cost of Electricity (LCoE): photovoltaic-batteries, photovoltaic-hydrogen-batteries, photovoltaic-diesel generator, and diesel generator; the influence of the location and the impact of different consumptions profiles is explored. Several simulations developed through specific modeling software are carried out and discussed. The main finding is that diesel-based systems still allow lower costs than any other solution, although hydrogen-based solutions can compete with other technologies under certain conditions. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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Review

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26 pages, 2054 KiB

Open AccessFeature PaperReview

Seed Pretreatment for Increased Hydrogen Production Using Mixed-Culture Systems with Advantages over Pure-Culture Systems

by Vinayak Laxman Pachapur, Prianka Kutty, Preetika Pachapur, Satinder Kaur Brar, Yann Le Bihan, Rosa Galvez-Cloutier and Gerardo Buelna

Energies 2019, 12(3), 530; https://doi.org/10.3390/en12030530 - 7 Feb 2019

Cited by 50 | Viewed by 6958

Abstract

Hydrogen is an important source of energy and is considered as the future energy carrier post-petroleum era. Nowadays hydrogen production through various methods is being explored and developed to minimize the production costs. Biological hydrogen production has remained an attractive option, highly economical [...] Read more.

Hydrogen is an important source of energy and is considered as the future energy carrier post-petroleum era. Nowadays hydrogen production through various methods is being explored and developed to minimize the production costs. Biological hydrogen production has remained an attractive option, highly economical despite low yields. The mixed-culture systems use undefined microbial consortia unlike pure-cultures that use defined microbial species for hydrogen production. This review summarizes mixed-culture system pretreatments such as heat, chemical (acid, alkali), microwave, ultrasound, aeration, and electric current, amongst others, and their combinations to improve the hydrogen yields. The literature representation of pretreatments in mixed-culture systems is as follows: 45–50% heat-treatment, 15–20% chemical, 5–10% microwave, 10–15% combined and 10–15% other treatment. In comparison to pure-culture mixed-culture offers several advantages, such as technical feasibility, minimum inoculum steps, minimum media supplements, ease of operation, and the fact it works on a wide spectrum of low-cost easily available organic wastes for valorization in hydrogen production. In comparison to pure-culture, mixed-culture can eliminate media sterilization (4 h), incubation step (18–36 h), media supplements cost ($4–6 for bioconversion of 1 kg crude glycerol (CG)) and around 10–15 Millijoule (MJ) of energy can be decreased for the single run. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Production, Storage and Utilization)

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