GreatPoint Energy, Cambridge, Mass.: Technology to convert coal into gas that costs 10% to 20% less than drilled natural gas and is cleaner than burning coal. So far, GreatPoint has raised $36 million.
MiaSole, Santa Clara, Calif.: Thin-film solar cells to be marketed as an inexpensive source of electricity for homeowners and businesses. The company is shipping a product sold through dealers. MiaSole has raised $21 million in venture capital.
Altra, Los Angeles: Building and acquiring ethanol plants in key locations around the U.S. The company started out making corn ethanol but is now developing systems for making cellulosic ethanol from cheap materials like corn stover and switchgrass. Altra has raised $170 million.
EEstor, Cedar Park, Tex.: A rechargeable battery that can store up to 10 times as much energy as a lead-acid battery at the same cost. One initial application will be powering electric cars. The company has raised $3 million from KPCB.
Lilliputian Systems, Woburn, Mass.: A micro solid oxide fuel cell on a silicon chip for use in portable devices. Lilliputian has raised $34 million from venture companies.