Environmental Impact Assessment of PEM Fuel Cell Combined Heat and Power Generation System for Residential Application Considering Cathode Catalyst Layer Degradation

Recently, fuel cell combined heat and power systems (FC-CGSs) for residential applications have received increasing attention. The International Electrotechnical Commission has issued a technical specification (TS 62282-9-101) for environmental impact assessment procedures of FC-CGSs based on the life cycle assessment, which considers global warming during the utilization stage and abiotic depletion during the manufacturing stage. In proton exchange membrane fuel cells (PEMFCs), platinum (Pt) used in the catalyst layer is a major contributor to abiotic depletion, and Pt loading affects power generation performance. In the present study, based on TS 62282-9-101, we evaluated the environmental impact of a 700 W scale PEMFC-CGS considering cathode catalyst degradation. Through Pt dissolution and Ostwald ripening modeling, the electrochemical surface area transition of the Pt catalyst was calculated. As a result of the 10-year evaluation, the daily power generation of the PEMFC-CGS decreased by 11% to 26%, and the annual global warming value increased by 5% due to the increased use of grid electricity. In addition, when Pt loading was varied between 0.2 mg/cm2 and 0.4 mg/cm2, the 10-year global warming values were reduced by 6.5% to 7.8% compared to the case without a FC-CGS

A Life Cycle Analysis on a Bio-DME production system considering the species of biomass feedstock in Japan and Papua New Guinea

This paper describes the performance and/or CO2 intensities of a Bio-DME (Biomass Di-methyl Ether) production system, considering the differences of biomass feedstock. In the past LCA studies on an energy chain model, there is little knowledge on the differences of biomass feedstock and/or available condition. Thus, in this paper, we selected Papua New Guinea (PNG) which has good potential for supply of an energy crop (a short rotation forestry), and Japan where wood remnants are available, as model areas. Also, we referred to 9 species of biomass feedstock of PNG, and to 8 species in Japan. The system boundary on our LCA consists of (1) the pre-treatment process, (2) the energy conversion process, and (3) the fuel transportation process. Especially, since the pre-treatment process has uncertainties related to the moisture content of biomass feedstock, as well as the distance from the cultivation site to the energy plant, we considered them by the Monte Carlo simulation. Next, we executed the process design of the Bio-DME production system based on the basic experimental results of pyrolysis and char gasification reactions. Due to these experiments, the gas components of pyrolysis and the gasification rate under H2O (steam) and CO2 were obtained. Also, we designed the pressurized fluid-bed gasification process. In a liquefaction process, that is, a synthesis process of DME, the result based on an equilibrium constant was used. In the proposed system, a steam turbine for an auxiliary power was assumed to be equipped, too. The energy efficiencies are 39.0-56.8 LHV-%, depending upon the biomass species. Consequently, CO2 intensities in the whole system were 16.3-47.2 g-CO2/MJ-DME in the Japan case, and 12.2-36.7 g-CO2/MJ-DME in the PNG one, respectively. Finally, using the results of CO2 intensities and energy efficiencies, we obtained the regression equations as parameters of hydrogen content and heating value of a feedstock. These equations will be extremely significant when we install the BTL (biomass-to-liquid, ex. Bio-DME) energy system in the near future, in order to mitigate CO2 emissions effectively, and to estimate the energy's efficiency.Bio-DME (Biomass Di-methyl Ether) LCA methodology Monte Carlo simulation The regression analysis

Biomass energy used in a sawmill

Biomass-energy systems are considered to be environmentally superior to traditional ones from the viewpoints of the CO2 mitigation and the effective utilization of resources. However, the energy cost of these systems tends to be higher than that of conventional fossil-fuel systems. Furthermore, the establishment of environmental business models is expected in the near future.In this paper, the environmental improvement and the economics of a biomass-energy system in a sawmill are analyzed by a comparison of a gasification-cogeneration system with a direct-combustion system using scrap-wood material as feedstock fuel. Especially, the break-even point for marketability of the business taking the surplus electric-power into consideration is estimated under the assumption of a renewable-energy purchase system, such as the renewable portfolio standard (RPS) implemented in Japan. Consequently, when biomass-related subsidies are applied, the break-even point of the purchase price of the electric power from the gasification cogeneration becomes 7.7 --> 35.7 yen/kW h. Furthermore, if the construction cost decreases by 10%, the break-even point of the purchase price will be cheaper by about 7.4 yen/kW h.Gasification cogeneration system Renewable portfolio standard Scrap-wood materials

Environmental impact assessment on polymer electrolyte fuel cell co-generation system, lithium-ion battery, and photovoltaic hybrid system combination and operation, considering performance degradation

In recent years, fuel cell co-generation systems (FC-CGS) have attracted attention for contributing to the environment and are becoming increasingly popular. Considering the current situation, technical specifications for general FC-CGS environmental impact assessments have been published by the International Electrotechnical Commission (IEC) Technical Committee 105 Working Group 14 (TC105WG14). Additionally, several combinations of renewable energy systems, energy storage, and energy-saving technologies have been proposed to obtain more environmental benefits. In this study, several scenarios for combining a polymer electrolyte fuel cell co-generation system (PEFC-CGS) with a battery and PV were created, system operation was discussed, and an environmental impact assessment was conducted. The evaluation was based on IEC standards, considering performance degradation during the usage phase. As a result, it was found that a system in which PEFC-CGS operated in load-following mode, combined with battery and PV, could reduce global warming potential (GWP) by about 36%. There was almost no difference in the PEFC-CGS degradation rate owing to the difference in the operating methods. However, the battery degradation rate showed approximately a 45% difference depending on the scenario. In addition, an environmental gain of ηeco−gain was proposed that expresses the reduction rate from the BAU scenario. Finally, a sensitivity analysis was conducted by changing the weather conditions. The results showed that even when solar radiation was varied, eco-gain was much better than when PV was not installed