Solar powered residential hydrogen fueling station

This paper presents a conceptual design of a solar powered hydrogen fueling station for a single family home in Wallingford, Connecticut, USA. Sixty high-efficiency monocrystalline silicon photovoltaic (PV) solar panels (Total capacity: 18.9 kW) account for approximately 94.7% of the hydrogen home’s power consumption. The fueling station consists of a 165 bar high pressure electrolyzer for on-site production of 2.24 kg/day of hydrogen, three-bank cascade configuration storage tanks (4.26 kg of H₂ at 350 bar) and a SAE J2600 compliant hydrogen nozzle. The system produces 0.8 kg/day of hydrogen for a fuel cell vehicle with an average commute of 56 km/day (Fuel mileage: 71 km/kg H₂). Safety codes and standards applicable at the facility are described, and a well-to-wheel analysis is performed to contrast the carbon dioxide emissions of conventional gasoline and fuel cell vehicles. The energy efficiency obtained by incorporating a solar-hydrogen system for residential applications is also computed.     

Hydrogen–natural gas blends fuelling passenger car engines: Combustion,emissions and well-to-wheels assessment

In this study, a state of the art passenger car natural gas engine was optimized for hydrogen–natural gas mixtures and high exhaust gas recirculation (EGR) rates in the major part of the engine map. The investigations involved stoichiometric combustion. With optimal combinations of spark timing and EGR rate, the achievements are efficiency increase with substantially lower engine-out NO_x while total unburned hydrocarbons or CO-engine-out emissions are only modestly affected. The efficiency is increased by 3% in the low load and by more than 5% in the medium-load domain. Increasing hydrogen content of the fuel accelerates combustion leading to the efficiency improvements. Combustion analysis showed that the increasing burning rates mainly affected the initial combustion phase (duration for 5% mass-fraction burned). Nevertheless, increase of the hydrogen fraction in the fuel over a certain threshold did not result in any efficiency increase in the medium loads. Loss analysis identified high wall heat losses as the main reason. Dedicated combustion chamber design may be able to avoid these losses and lead to additional efficiency benefits. Well-to-wheel analysis revealed paths for the production of the fuel blends still having overall energy requirements slightly higher than a diesel benchmark vehicle but reducing by 7% overall green house gas emissions.     

DIR-FCEV powered by different fuels – Part I: Well-to-wheel analysis for the Brazilian and Spanish contexts

This article describes the life cycle assessment of the Direct Internal Reforming Fuel Cell Electric Vehicle (DIR-FCEV) for the Brazilian and Spanish contexts. This recently proposed vehicle technology produces hydrogen onboard via heat recovery, while the Solid Oxide Fuel Cell (SOFC) and the gas turbine provide electricity to the electric motor with high overall efficiency. The exhaust gas emission was obtained via GASEQ software and the well-to-tank data were collected through literature search. These values were entered in the GREET Model software version v1.3.0.13656 to assess the negative environmental impacts of the DIR-FCEV in terms of global warming potential (GWP) and human toxicity potential (HTP). Using 1 km distance driven by a light-duty vehicle as the functional unit, the tank-to-wheel results indicate that regardless of the fuel, the DIR-FCEV achieved better than the internal combustion engine vehicle fuelled with gasoline A in both categories. Also, the DIR-FCEV powered by biomethane, gasoline A, gasoline C (73% gasoline A and 27% ethanol, in volume basis), glycerine, and ethanol attended all future tailpipe emissions standards stipulated by United States and European Union. Biomethane and gasoline-fuelled DIR-FCEV had more commendatory environmental performance in both countries. Thus, it is expected to obtain environmental indicators to stimulate the use of biofuels synergistically with the advancement of electromobility in Brazil and Spain.     

Well-to-wheel analysis of hydrogen fuel-cell electric vehicle in Korea

This study provides methodologies, data collection and results of well-to-wheel greenhouse gas analysis of various H₂ production pathways for fuel-cell electric vehicle (FCEV) in Korea; naphtha cracking, steam methane reforming, electrolysis and coke oven gas purification. The well-to-wheel (WTW) greenhouse gas emissions of FCEV are calculated as 32,571 to 249,332 g-CO₂ eq./GJ or 50.7 to 388.0 g-CO₂ eq./km depending on the H₂ production pathway. The landfill gas (on-site) pathway has the lowest GHG emissions because the carbon credit owing to use landfill gas. The electrolysis with Korean grid mix (on-site) pathway has the highest GHG emissions due to its high emission factor of the power generation process. Furthermore, the results are compared with other powertrain vehicles in Korea such as internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV) and electric vehicle (EV). The averaged WTW result of FCEV is 35% of ICEV, is 47% of HEV, and is 63% of EV.     

Cost and CO2 aspects of future vehicle options in Europe under new energy policy scenarios

New electrified vehicle concepts are about to enter the market in Europe. The expected gains in environmental performance for these new vehicle types are associated with higher technology costs. In parallel, the fuel efficiency of internal combustion engine vehicles and hybrids is continuously improved, which in turn advances their environmental performance but also leads to additional technology costs versus today’s vehicles. The present study compares the well-to-wheel CO₂ emissions, costs and CO₂ abatement costs of generic European cars, including a gasoline vehicle, diesel vehicle, gasoline hybrid, diesel hybrid, plug in hybrid and battery electric vehicle. The predictive comparison is done for the snapshots 2010, 2020 and 2030 under a new energy policy scenario for Europe. The results of the study show clearly that the electrification of vehicles offer significant possibilities to reduce specific CO₂ emissions in road transport, when supported by adequate policies to decarbonise the electricity generation. Additional technology costs for electrified vehicle types are an issue in the beginning, but can go down to enable payback periods of less than 5 years and very competitive CO₂ abatement costs, provided that market barriers can be overcome through targeted policy support that mainly addresses their initial cost penalty.     

CO2 emission balances for different black liquor gasification biorefinery concepts for production of electricity or second-generation liquid biofuels

Black liquor gasification (BLG) is currently being developed as an alternative technology for energy and chemical recovery at chemical pulp mills. This study examines how different assumptions regarding systems surrounding the pulp mill affect the CO₂ emission balances for different BLG concepts. The syngas from the gasification process can be used for different applications; this study considers production of renewable motor fuels and electricity generation. Both a market pulp mill and an integrated pulp and paper mill are considered as host mill for the BLG plant. Furthermore, the consequences of limited availability of biomass are shown, i.e., increasing the use of biomass in a mill is not necessarily CO₂-neutral. The results show that the potential to reduce CO₂ emissions by introducing BLG is generally much higher for a market pulp mill than for an integrated pulp and paper mill. Electricity generation from the syngas is favoured when assuming high grid electricity CO₂ emissions where as motor fuel production is favoured when assuming low grid electricity CO₂ emissions. When considering the consequences of limited availability of biomass, the CO₂ emission balances are strongly affected, in some cases changing the results from a decrease to an increase of the CO₂ emissions.     

Comparison of GHG emissions from diesel,biodiesel and natural gas refuse trucks of the City of Madrid

The aim of this paper is to carry out a comparative study with regard to energy consumption and greenhouse gas emissions, in respect of two types of engines with three different fuels. The fuels analysed are diesel, biodiesel 30% (B30) and compressed natural gas (CNG). The engines tested were a spark ignition engine (Otto cycle) and two compression ignition engines (Diesel cycle), the first fed with CNG and the last two with B30 and diesel. What is new about this study is its scope of application concerning refuse collection services in the city of Madrid. The tests were carried out on refuse trucks of the FCC Company along actual urban routes in the city of Madrid. Also taken into account were the energy input and the greenhouse gases emitted for each of the paths taken by the fuels analysed, from resource recovery to delivery to the vehicle tank.     

Well-to-wheel study of passenger vehicles in the Norwegian energy system

For the evaluation of potential routes for production and application of hydrogen in a future energy system, well-to-wheel (WtW) methodologies provide a means of comparing overall impacts of technologies and fuels in a consistent and transparent manner. Such analysis provides important background information for decision makers when implementing political incentives for the conversion to more environmentally friendly energy production and consumption. In this study, a WtW approach was applied in order to evaluate the energetic and environmental impacts of introducing hydrogen in the transportation sector, in terms of energy efficiency and emissions of CO₂ and NO_x, under conditions relevant for the Norwegian energy system. The hydrogen chains were compared to reference chains with conventional fuels.     

Design of a hydrogen community

This paper discusses the conceptual design of a scalable and reproducible hydrogen fueling station at Santa Monica, California. Hydrogen production using renewable energy sources such as biogas, which accounts for 100% of the total production, has been discussed. The fueling station consists of a direct fuel cell (DFC) 300 fuel cell for on-site generation of 136 kg/day of hydrogen and 300 kW of electric power, five hydrogen storage tanks (storage capacity of 198 kg of H₂ at 350 and 700 bar), four compressors which assist in dispensing 400 kg of hydrogen in 14 h, two hydrogen dispensers operating at 350 bar and 700 bar independently and a SAE J2600 compliant hydrogen nozzle. Potential early market customers for hydrogen fuel cells and their daily fuel requirements have been computed. The safety codes, potential failure modes and the methods to mitigate risks have been explained. A well-to-wheel analysis is performed to compare the emissions and the total energy requirements of conventional gasoline and fuel cell vehicles.     

A cost comparison of fuel-cell and battery electric vehicles

This paper compares the manufacturing and refueling costs of a fuel-cell vehicle (FCV) and a battery electric vehicle (BEV) using an automobile model reflecting the largest segment of light-duty vehicles. We use results from widely-cited government studies to compare the manufacturing and refueling costs of a BEV and a FCV capable of delivering 135 hp and driving approximately 300 miles. Our results show that a BEV performs far more favorably in terms of cost, energy efficiency, weight, and volume. The differences are particularly dramatic when we assume that energy is derived from renewable resources.