Geothermal Power

When you think about renewable energy, solar or wind power seem to come to mind first.  Maybe because photovoltaic farms and wind turbines make wonderful graphics for the news media.  But, there is another renewable energy source being used right now, just beneath our feet – geothermal energy.  Some may overlook it, but it is an abundant, reliable and environmentally-sound choice for the future.

Geothermal Power Basics

Geothermal power takes advantage of the heat beneath the earth’s surface (from hot water or steam reservoirs) to produce electricity or to use directly in heat-related manufacturing processes.

Geothermal power was once limited to areas near tectonic plate boundaries where magma is closer to the surface and heat from hot water or steam reservoirs is easily accessible. The Geysers, a hot springs in Northern California, is one such spot.  In 1960, Pacific Gas and Electric began operation of the first successful geothermal electric power plant in the United States there. It continues in operation today.

Now technological advances in deep drilling into the earth have expanded the available resources. The new enhanced geothermal systems (EGS) are greatly expanding the use of geothermal energy.  EGS first requires drilling into the earth and injecting water to fracture the hot rock.  The water is then circulated through the system and the steam produced is used to run a turbine to generate electricity.  The U. S. Department of Energy projects that more than 100,000 MWe of  capacity may be available in the continental United States. This would be an increase of 40 times the present geothermal power generating capacity.
See how EGS works in this video produced by Google:

Geothermal Disadvantages

While EGS seems a perfect replacement for coal-fired electric power plants, there are some downsides.  Geothermal faces the same obstacles as wind and solar, the initial capital investment is steep and when the price of oil and gas falls, it is difficult to find investors.  The 2009 stimulus package, however, offers some tax advantages for investors in geothermal.

In addition, further technological advances are needed for development of the complex pumps that can move great volumes of water through fractures in the deep, hot rock.
And, an unanticipated consequence of EGS may be increase earthquakes activity. Enhanced geothermal systems can trigger earthquakes as part of the hydraulic fracturing process. The project in Basel, Switzerland was suspended because more than 10,000 seismic events measuring up to 3.4 on the Richter scale occurred over the first 6 days of water injection.
The Geysers in California have seen a steady increase in seismic activity since the development of the geothermal power plant in 1960.

So far, water injection has not caused damaging earthquakes. Nonetheless, even in earthquake prone areas, small earthquakes cause public concern over EGS.

Conclusion
EGS has been described as the “sleeping giant” of renewable energy.

It’s clean, reliable and available.  With additional technological innovations and the right combination of government tax incentives and subsidies, geothermal power is set for huge growth.

Further reading

Press Democrat - The Geysers

Miller-McCune - emission free energy straight from nature

U.S. Dept of Energy - enhanced geothermal systems

Copyright 2009 — K.J.Collins