Geothermal Energy – Earth Driven Electricity

Geothermal Compares Favorably with Other Renewable Sources

Geothermal Energy originates from the heat stored in the earth, drawing from underground heated water and steam to drive electricity-generating turbines. In comparison to other well-accepted renewable technologies (e.g. wind and solar), geothermal energy:

• Is available 24/7 and avoids the challenges of variability or intermittent,
• Constitutes only 8 percent of the U.S. renewable electricity generation and 1 percent of the total U.S. electricity production, and
• Can potentially generate 350,000 MWh of electricity annually or over 10 percent of the current U.S. electricity needs.

Benefits of Geothermal Energy

The tangible benefits of geothermal create a compelling rationale for developing geothermal energy to its full potential:

• Virtually free of greenhouse gas (GHG) emissions: Geothermal plants typically produce less than one percent of the CO2 emissions per MWh of a coal-fueled power plant. Replacing a 500 MW coal-fired power plant with geothermal plants would have the net effect of eliminating over 3 million metric tons of CO2 annually.
• Minimal impact on the environment: The actual footprint required to support this technology is relatively small (power stations are positioned directly over the energy source). Geothermal energy requires little, if any, forest harvesting, no damming of rivers, and does not use mine shafts or tunnels.
• Inexhaustible supply: The temperature only a few miles below the earth’s surface is commonly estimated at about 500 degrees Fahrenheit and the original source of steam (underground water) is limitless.
• Reliable: With no reliance on external phenomena (e.g. wind strength, water levels, and sun exposure), the heat stored underground is available for producing electricity 24 hours every day.
• Total costs are reasonable: The capital costs associated with construction are equal to or higher than that of a typical fossil fuel power plant. However, their operating costs are significantly less, most notably because geothermal facilities do not require fuel to generate electricity. As drilling technology improves (a likely outcome of any increase in geothermal plant construction), even the capital costs related to construction will decrease (drilling costs represent almost 36 percent of a geothermal plant’s total capital cost).

Economic Challenges of Geothermal Energy

As with any emerging technology, there are obstacles and challenges to overcome:

• The exploratory phases require high levels of investment and often (75 percent of the times) result in failure.
• Uncertainty regarding climate-related regulation and government financial support impacts potential project developers, particularly given the 10-year time frame required to go from exploration to generation.
• The remoteness of the geothermal resources from large electricity consumption areas often requires the installation of additional transmission capacity across great distances, adding significantly to the cost of the projects.