Geothermal power is power generated from the heat stored underground in the Earth. Although not viable in every location, where it is present it is considered one of the most environmentally-friendly and cost-effective energy solutions over the long run. It is one of a handful of energy solutions looked to by advocates of environmental sensitivity as an alternative to fossil fuels, along with other renewable sources such as wind energy, tidal energy, solar energy, and occasionally hydropower.
Currently, geothermal power accounts for roughly 1% of the world’s total energy production, although this number is significantly higher in some regions. In Iceland, for example, more than 19% of total electrical energy comes from geothermal power, and 87% of all home heating comes from geothermal power. Because of the abundance of geothermal power, Iceland hopes to be the first nation to be completely fossil-fuel independent. The Philippines also make extensive use of geothermal power, with by some accounts more than 27% of all electricity generated by geothermal sources.
The United States, although not a massive producer of geothermal power relative to total power production, is still the world’s largest producer of geothermal power, and has the largest dry steam field in the world, in The Geysers in California. The Geysers alone have a capacity of 1360 megawatts (MW), while fields around the Salton Sea have another 570MW of capacity. Geothermal energy continues to be a growth area in the United States, especially as a greater emphasis is put on developing alternatives to traditional fossil fuels.
From an environmental standpoint, it’s difficult to find a more attractive option than geothermal power. Because the system is essentially a closed-loop, there are virtually no emissions, making it arguably the cleanest choice for energy production. Although other power sources, such as solar panels, also have no emissions, the treatments used in production of solar panels are much more environmentally degrading than building a geothermal plant to supply a comparable amount of energy.
From a land use perspective, geothermal is also incredibly positive as an energy source. While coal power plants require roughly nineteen acres per MW, and nuclear power plants require between five and ten acres per MW, geothermal plants can use as little as one acre per MW, and rarely more than eight acres per MW. Unlike many other plants, they are also very scalable, allowing small plants to be built to supply geothermal power to rural areas, and enormous plants to be built for metropolitan areas.
Geothermal energy is also largely renewable, as the reservoir of heat from the inside of the Earth is massive when compared to the amount used in power generation, even if scaled up enormously. Unlike other renewable sources like solar panels or wind turbines, geothermal energy is also very dependable. Because the energy source is the heat from the Earth itself, which fluctuates very little, energy is always available. This means that a geothermal plant can operate at around 90% of capacity year round, without experiencing fluctuations based on sunlight or seasonal wind patterns that plague other alternative sources.