Technology
Geothermal energy can produced from hot water, steam reservoirs and hot rocks deep in the earth and close to the surface in some areas.

Geothermal resources may be harnessed in large utility applications and also in smaller distributed power generators.  Utilities in places such as the western US have built geothermal power plants in the vicinity of large hot water resources to help service their electricity loads.  On a smaller scale, companies are commercializing technology that may help remote oil and gas drillers power some of their drilling operations with excess hot water and pressurized steam.

Market / Advantages
Conventional geothermal (use of hot water or steam to drive a steam turbine) is a mature technology that has been deployed throughout the western US and other pacific rim countries to take advantage of the hot fluids from volcanic formations.  Geothermal produced power has a global installed base of around 9,000 MW.

A major advantage of geothermal produced power compared to the other renewable resources is that it may be dispatched like traditional fossil fuel generation and is considered “baseload” generation.  Such a resource helps utilities more accurately plan and schedule power generation to meet their load demand.

Issues
Although the above-ground mechanics of geothermal power generation is technically relatively simple, the exploration and production of the resource can be risky.  Historically, power prices have not been able to sustain an adequate risk / reward balance to support a major build out of geothermal produced power.  However, with the recent increase in power prices and rig availability, the exploration and production of geothermal resources will continue to increase.