Most geothermal sources are suitable for power generation - those with temperatures above 300°F - are waaaaay down underground, beyond the reach of current technology. Bad news for those looking for relatively clean sources of electricity.

Lower-temperature resources on the other hand are quite common across the United States However, if the Engineers at United Technologies Research Center (UTRC), have their way, those not-so-hot resources can be tapped for energy as well.

The modular, 200-kilowatt power plant from UTRC can generate juice from temperatures as low as 165°F. The technology is similar to steam engines, except that steam or hot water vaporizes a hydroflourocarbon refrigerant that drives the turbine. It's basically like a reverse cooling system, and the new turbine is a refrigerator compressor running backwards.

They're now testing a unit at a remote hot springs resort 60 miles northeast of Fairbanks, Alaska. They estimate that a commercial plant could be ready as early as next year... of course after they've worked out the chinks.

The reverse cooling concept isn't new, it's just that so far, nobody has come up with a cost-efficient model. In fact, most of Western united states have low-temperature geothermal sources. But if the model succeeds then we could be looking at a huge secondary source of energy.

I wonder how things will go if they manage to combine this technology with this. We know that those really small turbines don't exactly run on steam, but what if?