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Article updated on 27 April 2020
With an almost unlimited amount of heat generated by the Earth’s core, geothermal energy can be extracted without burning any fossil fuels. However, geothermal energy is still considered as the underdog of renewable energy due to limited resources. In January 2020, three companies in the US state of California took the initiative to change the future of geothermal energy.
What is a Geothermal Energy Plant and Where are they Currently Used in the World?
Within the sub-surface of the Earth, there exists a considerable amount of water and steam that carry geothermal energy to the planet’s surface. Geothermal energy begins with energy companies drilling wells that allow for direct access to the super-heated liquid, otherwise known as “brine,” that is located thousands of feet below the ground. As the brine is pumped out of the earth, it flows through various pipes, allowing for the pressure of this liquid, which is naturally heated to temperatures higher than 500 °F, to decrease gradually. Like any other power plant, the steam is collected and brought to turbines that eventually generate electricity. Any cooled water that does not get converted into electricity is re-injected into the drilling well to replenish the reservoir.
As a renewable and clean energy source, geothermal energy plants are capable of gathering electricity 24 hours a day and seven days per week. This is significant when compared to the energy obtained by other green energy sources such as solar panels and wind turbines.
In addition to being free from time and weather constraints, geothermal energy also has very high capacity factors. Many countries around the world, including Iceland, El Salvador, New Zealand, Kenya, and the Philippines, have benefitted from the advantages of geothermal energy to supply their baseload electricity. It is estimated that approximately 90% of the heating demand in Iceland is addressed through the use of geothermal energy.
What are the Challenges of Geothermal Energy?
Although geothermal energy is widely used for the heating and cooling of commercial buildings and residential homes around the world, there are several challenges that energy providers continue to face when attempting to capture geothermal energy for electricity production. Some of these limitations include high costs and the sparse availability of medium to high-temperature resources for electricity generation, as they are typically located near tectonically active regions.
Overcoming Geothermal Limitations
A recent U.S. Geological Survey estimates that California is home to nearly 15,000 megawatts of geothermal potential. However, this number is expected to rise as more energy companies develop technologies that are capable of reaching deeper and lower-temperature geothermal reservoirs.
Various federal initiatives, particularly the U.S. Department of Energy’s Frontier Observatory for Research in Geothermal Energy (FORGE), have been created to support efforts aimed towards advancing the technology behind geothermal energy acquisition. In 2019, approximately $140 million USD was awarded to the University of Utah, which operates a field laboratory to evaluate such revolutionary techniques.
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As more work is being done to improve the technology of geothermal energy power plants while simultaneously reducing the costs associated with them, a significant rise in geothermal capacity is expected. By the year 2050, researchers anticipate that the US could generate up to 60,000 megawatts of geothermal energy, which is significantly more than the 2,500 megawatts that are currently produced in this nation. This increase would mean that up to 16% of the electricity generated throughout the US would be acquired from geothermal power plants.
The Impact of Geothermal Energy in California
Approximately 4.5% of total current electricity is provided by geothermal energy in the state of California. As demonstrated in Table 1, this is a small amount as compared to the 34.9% of the electricity that is generated by natural gas in this state.
Table 1: A brief overview of the energy sources of electricity in California.
% electricity mix
In 2018, to reduce California’s dependence on non-renewable energy sources, California lawmakers mandated that 100% climate-friendly electricity would need to be achieved by 2045. To accomplish this, energy providers across the third-largest US state have increased their commitment to opening up larger, more efficient and emission-free energy power plants. In January 2020, three different energy providers in California signed contracts that will allow their companies to capture electricity generated in California’s newest geothermal power plants.
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The Imperial Valley
Located near the Salton Sea in Southern California is the Imperial Valley. Currently, there are 11 operating geothermal plants in Imperial Valley, 10 of which are owned by Warren Buffet’s Berkshire Hathaway Energy and one of which is owned by EnergySource.
As of January 7, 2020, Controlled Thermal Resources (CTR), an Australian company with headquarters also located in California, and the Imperial Irrigation District (IID) entered a Power Purchase Agreement (PPA) for 40 megawatts (MW) of renewable power that will span a period of 25 years. At a projected value of approximately $627 million USD, this PPA ensures a long-term supply of geothermal energy for the California grid.
Lithium Extraction Plans at the Imperial Valley Plant
CTR Li + Power Animation
Video Credit: Controlled Thermal Resources/YouTube.com
With an anticipated completion date in 2023, the Imperial Valley plant will not only increase geothermal energy production but will also integrate direct lithium extraction from the fluid that will be used to generate electricity. As compared to traditional lithium extraction methods that involve hard rock and evaporation pond mining, both of which pose certain hazards to the environment, lithium can also be extracted from geothermal brines.
Through a process known as direct lithium extraction (DLE), a closed-loop system returns spent brine to its original source, ensuring that all power and steam involved in the processing of this important element is completely renewable. Furthermore, DLE is much more cost-effective, as it only requires several hours to be completed, which is comparable to the several months associated with traditional lithium extraction methods. DLE is also advantageous for its close-to-zero carbon footprint, its ability to produce high purity lithium products, and can be performed during any type of weather conditions.
As rechargeable lithium-ion batteries continue to be incorporated into electric cars, energy storage systems and smartphones, this new project will create a more sustainable and resilient supply chain of this valuable element within the United States. Once CTR acquires the financing it needs to begin drilling delineation wells, it anticipates that the Hell’s Kitchen project will produce 17,350 tons of lithium by 2023 and up to 34,700 tons per year by 2025.
Notably, the Salton Sea wells are home to high lithium concentrations that can be produced at equivalent flow rates, which has not been discovered at any other geothermal sites around the world that also mine for lithium.
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Future Impact of the Californian Geothermal Power Plant
Since 2012, California has not constructed any new geothermal power plants. The impressive size and outlook for this state’s latest geothermal project will undoubtedly demonstrate to the world how this energy source can provide dependable and clean electricity.
References and Further Reading
International Renewable Energy Agency. Geothermal energy. [Online] Available at: https://www.irena.org/geothermal (Accessed on 1 April 2020).
Roth, S. (2020) California needs clean energy after sundown. Is the answer under our feet? [Online] Los Angeles Times. Available at: https://www.latimes.com/environment/story/2020-01-22/california-needs-clean-energy-after-sundown-geothermal-could-be-the-answer (Accessed on 1 April 2020).
BHE Renewables. Imperial Valley (United States) [Online] Available at: https://www.bherenewables.com/ (Accessed on 1 April 2020).
Roth, S. ( 2019) Imperial Valley Hopes to Compete in Lithium Extraction [Online] Available at: https://www.governing.com/news/headlines/Imperial-Valley-Hopes-to-Compete-in-Lithium-Extraction.html (Accessed on 1 April 2020).
Richter, A. (2020) Controlled Thermal Resources secures geothermal PPA in the Imperial Valley, California. Think Geoenergy. [Online] Available at: https://www.thinkgeoenergy.com/controlled-thermal-resources-secures-geothermal-ppa-in-the-imperial-valley-california/ (Accessed on 1 April 2020).
Controlled Thermal Resources. IID & CTR lead the charge for renewable energy in the U.S. with 40MW PPA. [Online] Available at: https://www.cthermal.com/latest-news/iid-amp-ctr-lead-the-charge-for-renewable-energy-in-the-us (Accessed on 27 April 2020).