Fuel cells
When oxygen is combined with hydrogen, the products are water and electricity. Fuel cells exploit this chemical reaction, pulling oxygen from the air and hydrogen from a fuel source such as natural gas. Used by NASA for generating power in space, fuel cells are now being developed for both stationary use and mobile applications (cars, camping).
Microgrids
Software-synchronized networks of micropower generators.
Microturbines
Small-scale turbines that generate electricity by spinning a magnet inside a coil at extremely high speeds. Fueled by a variety of gases. Less efficient than fuel cells, but cheaper; efficiencies are higher if microturbine waste heat can also be used on-site (a process called "cogeneration").
Photovoltaics
Also known as solar cells, photovoltaics convert sunlight to electricity. Costs are high but the fuel is free, and maintenance costs are low.
Reciprocating engines
Refined versions of internal combustion engines provide more efficient output and lower emissions. Currently lower cost, but higher emissions and higher maintenance needs than other emerging micropower technologies.
Super-capacitors and flywheels
Short-term storage devices for electricity to smooth transitions on and off the grid.
Wind turbines
Wind turbines are often deployed in large "farm" arrays, but can also
be installed on-site in single-user micropower applications.
See January 2001 fedgazette.
For more information:
Electric Power Research Institute
Energy Efficiency and Renewable Energy, U.S. Department of Energy
Worldwatch Paper #151: Micropower: The Next Electrical Era