Fuel Cells

A fuel cell is a device that uses a fuel and oxygen to create electricity by an electrochemical process.  A single fuel cell consists of an electrolyte and two catalyst-coated electrodes (a porous anode and cathode). Fuel cells are classified primarily by the electrolyte used.   This categorization determines the kind of chemical reactions that take place in the cell, the kind of catalysts required, and other factors, which, in turn, determines the applications for which these cells are most suitable.  Fuel cells function as a type of “continuous battery.” Startup time can be 1-4 hours, but once fuel cells are running, they are capable of cycling with variable loads. 

Fuel Cell Technology Options

 Polymer Electrolyte Membrane (PEMFC)Alkaline (AFC)Phosphoric Acid (PAFC)Molten Carbonate (MCFC)Solid Oxide (SOFC)
Electrical Efficiency25-35%32-40%35-45%40-50%45-55%
ApplicationsBackup power, Portable power, TransportationMilitary, SpaceDistributed generation (DG)Electric utility, DGAuxiliary power, Electric utility, DG
Typical System Size<1kW – 100kW10-100kW400kW, 100kW module300kW-3 MW; 300 kW module1kW-2MW

Gas engines power water pumps at several water agencies in California. These gas engines are subject to local emissions regulations which can impose limitations on their use. A fuel cell in combination with an electric motor could be installed to replace the gas engine to power the pump as a zero-emission solution that is also a more efficient use of gas.

Cost and Energy Savings

Costs been noted to range from $4,500 to $30,000/kW depending on the type of fuel cell. While the initial capital cost of fuel cells is much greater than internal combustion engines (ICE), fuel cells are an attractive alternative due to their ultra low emissions, higher efficiency, lower operating noise, and lower maintenance time required.

An ICE has an electrical efficiency of 30-35% while fuel cells can have an electrical efficiency of 50%. Fuel cell energy savings impacts are greatest when operating in a combined heat and power (CHP) where savings can reach 20-40% over ICE’s.

Challenges

The main challenges or barriers to fuel cell adoption have been: insufficient reliability, high installed cost and lack of a fuel infrastructure (for fuel cells that require special fuels).  The US DOE believes that more than 40,000 hours of reliable operation is needed for market acceptance. Challenges specific to pumping station applications are noted below in the case study section.

Case Studies

  • Eastern Municipal Water District
  • Rancho California Water District
  • City of San Diego, California

Additional Sources

  • U.S. Department of Energy. Fuel Cell Technical Publications.
  • Pumping Water with Fuel Cells – Rancho California Water District’s Fuel Cell  Project at the ACE Bowen Pump Station.CA/NV AWWA Spring Conference, March 2011.