Washington, DC [RenewableEnergyAccess.com] To help prospective buyers of alternative fuel-cell technologies assess their residential economic value, the National Institute of Standards and Technology (NIST) has developed a new performance rating system to accommodate seasonal or demand changes. Residential fuel cells now being developed combine hydrogen from natural gas or propane with oxygen from the air to produce electricity.Currently, PTC 50, an ASME standard, is used to measure fuel cell system performance, but it does not take into account either seasonal changes in heating and cooling requirements, or a residence’s quickly changing demands for electricity. To bridge the gap between the PTC 50 standard and the information that consumers will need to make economic decisions on installing a fuel cell, NIST researchers published proposed test and rating methods (see link below) to help consumers assess the economic feasibility of four types of residential fuel cells under different climate conditions in six different geographic locations. The rating will provide the annual electrical energy produced, fuel consumed, thermal energy for domestic water heating and space heating delivered, and water used by the residential fuel cell system. Several manufacturers have provided input on the rating methodology. The NIST researchers expect to present their test methodology and performance rating procedures to standards organizations this summer.