Geothermal energy is renewable energy produced from the earth’s core. It comes from heat generated during the planet’s original formation and the radioactive decay of materials. The storage for thermal energy is in rocks and fluids in the earth’s centre. The difference between the temperature in the earth’s core and the surface drives the continuous conduction of thermal energy from the centre to the planet’s exterior. High temperatures of over 4000°c can cause some rocks in the earth’s centre to melt and form a hot molten rock called magma, which can be indirectly used to generate energy.
Geothermal energy is usable in any location with a geothermal resource, such as hot springs, geysers, and volcanic activity. Some countries, such as Iceland, New Zealand, and Kenya, have a higher concentration of geothermal resources and utilise this energy source for a significant portion of their electricity demands.
Some advantages of Geothermal Energy are:
- Geothermal energy is a very reliable power source: Geothermal energy is a very predictable and reliable energy source compared to other renewable energy sources like wind and solar energy. While wind and solar are more intermittent sources that require energy storage to be used effectively at a large scale, geothermal power plants have a consistent power output irrespective of time or season. This has many positive impacts, notably that geothermal power is appropriate for meeting base load energy demand.
- Geothermal power plants have a small land footprint: Another advantage of geothermal power plants over other large-scale wind power, solar energy, or hydroelectric installations is the relatively low footprint of a geothermal plant. This is because geothermal energy comes from within the earth, and we don’t need to build out collection setups over large swaths of land surface to harness it. For reference, National Geographic estimates that a geothermal power plant capable of producing one gigawatt-hour (GWh) of electricity would take up approximately 404 square miles of land surface. At the same time, a wind farm with the same energy output would need about 1,335 square miles, and a solar farm would need about 2,340 square miles. That’s 88 per cent less space for a geothermal power plant than a solar farm, both sized at one GWh.
- There are large-scale and small-scale applications for geothermal power: Geothermal energy isn’t just for large power plants. One of the most efficient ways to use heat from the earth is to harness it with a geothermal heat pump for a residential or commercial building. Unlike geothermal power plants, geothermal heat pumps use low-temperature geothermal reservoirs that can be resourced.
- Geothermal energy infrastructure has longevity: Geothermal heating and cooling systems have a very long lifespan compared to many other green energy solutions. The US Department of Energy estimates a 20-year lifespan for heat pumps and up to 50 years for the underground infrastructure.
Finally, there are most likely just three geothermal energy locations in Nigeria. The Ikogosi warm spring (37°c) is in the southwestern part of the nation, in Ekiti. Others include the Wikki warm spring (39°c) spotted in Bauchi (North-eastern) and the RafinRewa spring (42°c) found in the Plateau (North-focal) condition of Nigeria. However, there is no direct application of geothermal energy for electricity production in Nigeria. The construction of geothermal plants in Nigeria needs to complement other renewable energy in power generation.