Since the 1970s, geothermal power has been a growing energy source worldwide.
Figure 1: Worldwide installed and construction geothermal capacity (Geothermal Energy Association, 2013)
Benefits of Geothermal Power
Base-load capacity: Geothermal power sources operate continuously 24 hours a day, 7 days a week. Utilities generally favor this type of base-load energy source vs. intermittent power sources such as wind or solar.
Consistent, low operational cost: Once operational, geothermal power sources have no fuel costs, unlike other base-load energy sources such as coal or natural gas where prices are unstable and can become extremely unfavorable in times of energy crisis.
Clean/sustainable energy source: Modern closed-loop geothermal power plants emit no greenhouse gasses. Life-cycle greenhouse gas emissions (50 g CO2 eq/kWhe) are four times less than solar Photovoltaic (PV) and six to 20 times lower than natural gas. Geothermal power plants consume less water on average over the lifetime energy output than most conventional generation technologies. Through proper reservoir management, the rate of energy extraction can be balanced with a reservoir’s natural heat recharge rate (Department of Energy).
Low average cost of power: Over the course of an average 30-year plant operations lifecycle, the cost of producing geothermal power is lower than or competitive with all other energy sources.
Geothermal is an Abundant Energy Source
Estimates of the worldwide electricity generating potential of geothermal energy vary from 35 to 2000 Gigawatts (GW) depending on the scale of investments. This does not include non-electric heat recovered by co-generation, geothermal heat pumps and other direct use. A 2006 report by the Massachusetts Institute of Technology (MIT) that included the potential of enhanced geothermal systems estimated that investing $1 billion U.S. dollars in research and development over 15 years would allow the creation of 100 GW of electrical generating capacity in the United States alone by 2050. The MIT report estimated that over 200 zettajoules (ZJ) would be extractable (more than the entire reported energy use on Earth in 2013), with the potential to increase this to over 2,000 ZJ with technology improvements - sufficient to provide all of the world's energy needs for several millennia.