The earth's core contains magma and molten rock, and for thousands of years, humankind has used that heat via geysers and hot springs for heating, bathing and cooking. Today, many countries harness that hot water and steam to generate electricity. Geothermal energy is also used to directly heat buildings, dry crops and melt snow.
How does it work?
Geothermal systems extract steam or hot water from the earth's core. A geothermal heat pump system captures underground reservoirs of steam and hot water to generate electricity. There are three types of geothermal power plants. Dry steam power plants focus on steam, while flash steam power plants use hot water. Wet steam or binary cycle power plants use a mixture of both.
Timeline of geothermal energy
Romans build bathhouses around hot springs.1 For centuries before and after, Chinese, Japanese, Native Americans and other indigenous peoples use the heat from hot springs for warmth, bathing and cooking.
A small town in France called Chaudes-Aigues (translates to hot waters) develops the first documented geothermal district heating system.1 Over 30 natural hot springs heat homes via wooden pipes.
The Hot Lake Hotel opens in Oregon, United States.2 The hotel/luxury resort is built alongside hot springs on the rural property. The Hot Lake Hotel is also the world's first commercial building to use geothermal energy as its primary heat source.
The first geothermal district heating system in the United States is created in Boise, Idaho.3 The city capitalises on the region's geology and completes two geothermal wells. Geothermal water heats over 200 homes and buildings.
Italian businessman, Piero Ginori Conti, develops the first geothermal-generated electricity.4 Conti powers five lightbulbs via a dynamo driven by a steam engine using geothermal energy. In 1911, Conti builds the first commercial geothermal power plant in Larderello, Italy.4
The first commercial geothermal heat pump is used to heat the commonwealth building in Portland.5 The geothermal heat pump is a central heating/cooling system that transfers heat to and from the ground. The use of this technology reduces the building's energy costs.
The world's first 'wet steam' geothermal power plant opens Wairakei, New Zealand - located in the Taupo Volcanic Zone.6
By the early 1980s, there are geothermal energy plants in multiple countries around the world, including Iceland, Indonesia, Turkey, the Philippines and Portugal. This is off the back of much government-funded research into the technology following the 1973 oil crisis.
Geothermal energy is behind other renewables sources for commercial use. Unlike solar, hydro and wind energies, geothermal energy is less readily available because it relies on geological characteristics (most geothermal resources are found along tectonic plate boundaries).
The future of geothermal energy
In 2015, the Global Geothermal Alliance said they aim to achieve fivefold growth in installed capacity of geothermal power generation and more than twofold growth in geothermal heating by 2030.7
More about evolution of renewable sources on https://www.comparethemarket.com.au/energy/history-renewable-energy/