The U.S. Department of Energy has issued a Funding Opportunity Announcement that will seek to award up to $12 million to marine energy research projects. This follows $7.3 million issued for marine power last year. The projects can run the gamut, from conventional hydropower to wave machines and beyond. You've heard of the usual ones -- underwater tidal turbines, wave bobbers, etc. Now here are some of the more unusual concepts:

• Small hydroelectric power stations that harvest electricity from the excess pressure inside municipal water systems. Call it microhydro.

• Electricity from osmotic pressure gradients, i.e., the pressure differences that can be created when fresh water meets sea water. Aquaporin in Denmark, among others looking at it.

2009 has not been the best year for marine energy. Pelamis hid, but eventually had to confess, that the three wave devices it put off the coast of Portugal last year are actually no longer at sea. Aquamarine scrapped tidal power, but kept wave. Still, if standards get developed, it could take off. Although much of the tidal work takes place in Ireland and the U.K., startups and researchers are also clustered around California, Florida, Australia and South Africa.