Pros
Clean – Generating electricity with geothermal energy helps to conserve nonrenewable fossil fuels, and by decreasing the use of these fuels, we reduce emissions that harm our atmosphere. The only emission is water vapor.
Reliable – Geothermal power plants are designed to run non-stop and are resistant to interruptions from weather, natural disasters or political rifts. To date, no geothermal field has been exhausted, however some have had pressure or temperatures reduced from the production.
Modular – Geothermal power plants can have modular designs, with additional units installed in increments when needed to fit growing demand for electricity.
Remote Locations – Geothermal projects can be installed in any location where the underground properties are in place. This can help power locations in developing countries or distant locations where running power lines would be cost inefficient.
Land Friendly – Geothermal plants require a low amount of land use and have a minimal impact on the surrounding environment.
No Fuel – The fuel that powers geothermal is water in a closed loop. The earth naturally heats the water, which is pumped up and turned to electricity before returning back into the ground for reheating, thus completing the cycle.
Land Friendly – Geothermal plants require a low amount of land use and have a minimal impact on the surrounding environment.
Low Operating Costs – Once installed, geothermal plants require few ongoing costs as the plants are a constantly running, closed loop system that is fueled from the earth.
Low Noise – Geothermal plants do not create high noise levels. The Puna Geothermal plant in Hawaii releases real-time noise levels found here (60dB is the equivalent of a casual indoor conversation at 3 feet).
Cons
Cannot Be Built Everywhere – Geothermal plants can only be built in areas with geothermal properties, which are quite limited globally. A map of the geothermal hotspots in the U.S. can be found here.
Reduced Efficiency – Over time, it is possible that the pumped water could cool, which would lower efficiency and output. Reservoirs could also dry out over time, although this has not occurred at any plants to date.
Capital Costs – The initial capital outlay may be prohibitive based on the characteristics of the reservoir and the depth of the wells. Initial wells drilled may also prove to be unviable.