Natural geothermal energy is one of the most abundant clean energy sources on Earth. It is derived from ‘Geo’ meaning Earth and ‘Thermal’ meaning heat. So this term refers to the heat from the Earth created by seismic and other geological phenomena.
Geothermal energy can be used for electricity and heating and cooling. Many countries, including the US, are increasing their use of geothermal energy in commercial and residential applications to offset fossil fuels and reduce their carbon footprint.
There are some fascinating facts around geothermal energy:
- The US has the largest geothermal plant in the world
- The first geothermal plant was built more than 100 years ago
- Geothermal has one of the lowest carbon footprints in the world
- Geothermal energy can heat, cool, and supply electricity
Let’s explore these and a few more amazing facts about geothermal energy in some more detail.
Where Is The Largest Geothermal Plant In The World?
California’s Geyser Geothermal Complex is the single largest geothermal plant globally and has 18 geothermal power plants on-site and this geothermal field is also the oldest in the US.
California, Utah, Idaho, Nevada, and Hawaii are the most extensive geothermal energy producers in the USA. The US Dept Of Energy projects that by the year 2050, geothermal energy could account for around 10% of electricity supplied in the USA.
Temperatures in the Earth where geothermal energy is found can be more than 9000°F, and the temperature increases by 5.4°F for every 328 feet you descend into the Earth.
When Was The First Geothermal Plant Built?
The first geothermal plant was set up in Larderello, Italy, in 1904, and it powered four light bulbs which were considered a remarkable achievement at the time.
What Is The Oldest Use Of Geothermal Energy?
The oldest hot spring was built in Lisan, China, in 3BC and is still in use today and even the Romans used geothermal energy around 2000 years ago. So this form of energy has been around human civilizations for a long time.
Geothermal Is Environmentally Friendly
Compared to coal, geothermal energy has a far lower carbon footprint emitting 45 kg per megawatt of carbon per kilowatt-hour of electricity produced, compared to 1001kg or 1,001 tons of CO2 of a coal-fired power station without carbon storage and capture.
As the commitment by world governments to reducing greenhouses gases gains momentum, geothermal energy is going to see greater application in electricity generation in years to come.
The Three Types Of Geothermal Energy Power Stations
Three types of power stations utilize geothermal energy.
- Dry steam power stations and steam at 302°F generated directly to drive turbines that generate electricity. This is not the most common form of geothermal energy as the direct steam source is not readily available.
- Flash steam power stations utilize high-pressure heated water from deep, transfer it to low-pressure tanks, and use the steam generated to drive turbines. The water temperature required needs to be at 360°F or higher.
- Binary cycle power stations are the most common facilities being built today. They use water at much lower temperatures, as little as 134°F, passed over a secondary liquid with a significantly lower boiling point than water. The flash steam created is used to power the turbines.
Geothermal Energy Is Versatile
The development of geothermal technology generates electricity and heating and cooling for homes and businesses. Steam creates electricity through turbines fed back into the grid from geothermal power stations.
Iceland uses the power of geothermal energy to heat homes and supply electricity. They also use it under their roads and sidewalks to melt the ice.
Around 90% of all homes in Iceland are heated using geothermal energy, and 26% of its total electricity is provided from this source. Using heat pumps to reverse the heat flow, geothermal energy can also cool homes.
These systems only need to be installed just 10 feet underground as the temperature is consistently around 50°F-60°F all year round, and the cost of the system would be around $3000 – $8000 and once installed would use no additional electricity.
This means that you could heat and cool your home with hot water for bathing and warming your pool for nothing outside of the installation cost!
Let’s look at a few more geothermal facts!
What Is The Energy Capacity Of Geothermal Power?
In 2019, the estimated geothermal capacity globally amounted to 15,4 Gigawatts, with around 24% installed in the USA. Today, this would be around the 20 GW mark, with annual averages of about 5% expected per annum.
The US Geological Survey has identified more than 22 000 MW in potential geothermal sites in the US that could be used for electrical generation and lower temperature sources suitable for heat pumps and direct use.
The Intergovernmental Institute on Climate Change estimates the global geothermal power potential from 35 GW to 2TW (Terawatts), and currently, less than 7% of the total potential is being utilized.
Geothermal heating is used in more than 70 countries, and more than 26 countries produce electricity using geothermal power.
Projections are that by the year 2100, geothermal power could account for as much as 10% of the global electricity supply.
How Long Could Geothermal Power Last?
Since geothermal energy comes from deep in the Earth, it is not an infinite resource but has a lifespan from around 5000 years to a million years!
Considering that the first plant was only built-in in 1904, and we’ve been using it for just over 100 years, we have some time to refine and optimize this fantastic clean source of energy.
However, the reality is that a geothermal site could shut down entirely after a few decades of production. With new binary power stations, even lower-temperature water could regenerate electricity production.
Geothermal Is The Third Largest Source Of Renewable Energy
The top sources of renewable energy are hydropower and biomass, with geothermal being the third. Remember that the current geothermal usage is only about 7% of the global potential, so geothermal will undoubtedly grow in the future.
Another geothermal fact is that it’s always on and isn’t dependent on a variable source like solar. The most significant cost involved is the drilling required to access the geothermal sources.
Did you know that the price of electricity produced by new geothermal plants is between $0.05 and $0.08 per kWh?