Fuel cell. Technicians assembling a hot module fuel cell prior to testing. At right is the stack of fuel cells surrounded by heating coils and gas circulators. It will be moved into the cylindrical oven (centre). This hot module cell uses chemical reactions to produce up to 3 megawatts of electricity. The cells are kept at 650 degrees celsius, with molten potassium carbonate and lithium carbonate as the electrolytes. Its only waste product is steam. Fuel cells are being studied as modern power sources as they are clean, efficient and portable. This cell can be transported by train. Fuel cells are hoped to be alternatives to large, costly power stations.