© 2021 Iceland Renewable Energy Cluster
What is geothermal energy?
Geothermal energy is thermal energy generated and stored in the Earth. The geothermal energy of the Earth’s crust originates from the original formation of the planet. Geothermal is location specific i.e. a resource must exist. Access to the resource is gained by drilling and getting access to steam or hot water. Geothermal is a base-load renewable energy resources.
What are the benefits of using geothermal energy?
Through proper reservoir management, the rate of energy extraction can be balanced with a reservoir’s natural heat recharge rate.
Geothermal power plants produce electricity consistently, running 24 hours per day / 7 days per week, regardless of weather conditions.
Geothermal power plants are compact; using less land per GWh (404 m2) than coal (3642 m2) wind (1335 m2) or solar PV with center station (3237 m2)
Some hydropower facilities can quickly go from zero power to maximum output. Because hydropower plants can generate power to the grid immediately, they provide essential back-up power during major electricity outages or disruptions.
Modern closed-loop geothermal power plants emit no greenhouse gasses; life cycle GHG emissions (50 g CO2 eq/kWhe) are four times less than solar PV, and six to 20 times lower than natural gas.
Frequently asked questions
Why is geothermal energy a renewable resource?
Because its source is the almost unlimited amount of heat generated by the Earth's core. Even in geothermal areas dependent on a reservoir of hot water, the volume taken out can be re-injected, making it a sustainable energy source.
Where is geothermal energy available?
Hydrothermal resources - reservoirs of steam or hot water - are available primarily closed to a body of water and near geologically active zones. However, Earth energy can be tapped almost anywhere with geothermal heat pumps and direct-use applications. Other enormous and world-wide geothermal resources - hot dry rock and magma, for example - are awaiting further technology development.
Is it possible to deplete geothermal reservoirs?
The long-term sustainability of geothermal energy production has been demonstrated at the Lardarello field in Italy since 1913 and at the Krafla field in Iceland since 1969. Pressure and production declines have been experienced at some plants, and operators have begun reinjecting water to maintain reservoir pressure.
What are the environmental impacts of using geothermal energy?
Emissions are low. Only excess steam is emitted by geothermal flash plants. No air emissions or liquids are discharged by binary geothermal plants. Salts and dissolved minerals contained in geothermal fluids are usually reinjected with excess water back into the reservoir.