Geothermal Energy: Promising, Massive, and Vastly-Underutilized
- Aug 17, 2021 4:30 pm GMT
In the first months of the Biden Administration, we’re seeing the advancement of a variety of energy projects, most of them utility-scale renewables, including the first large offshore wind park already permitted, the Vineyard Wind project, sited twelve nautical miles off Martha’s Vineyard. The $3 billion, 800-megawatt project will create 3,600 jobs and provide enough power for 400,000 homes from up to eighty-four turbines. Announced back in mid-May, Secretary of the Interior Deb Haaland noted at the time “A clean energy future is within our grasp in the United States. The approval of this project is an important step toward advancing the Administration's goals to create good-paying union jobs while combatting climate change and powering our nation.” Biden’s plan also includes both solar PV and solar thermal plants, and the just-passed infrastructure bill, should it get to the president’s desk for signature, includes $78 billion of vaguely-defined improvements to the “grid.”
In addition to a large number of additional planned offshore wind projects, Biden’s pre-election platform promised an intense effort to develop and commercialize grid-scale energy storage at a fraction of the cost of lithium-ion batteries; small modular nuclear reactors at half the construction cost of today’s reactors; zero net-energy buildings at zero net cost; using renewables to produce carbon-free hydrogen at the cost of shale gas; and a vast expansion of electric vehicles including POVs as well as transit fleets.
But nowhere do we see even a scant mention of geothermal energy, which is both astonishing and a major missed opportunity. Simply put, geothermal energy is a beneficial use of the heat generated at relatively-shallow depths underneath the earth’s crust. It’s an ideal and truly renewable energy source that can be used for heating and for generating electricity—because it’s abundant, reliable, predictable, and clean. And it can be leveraged easily if three conditions obtain: heat, hot water or steam, and permeable rock. Geothermal power plants can operate efficiently for decades, and because of their reliability, can produce a constant flow of baseload power, assuming the amount of energy extracted is synchronized with the rate at which the underground rock is able to renew its heat. In fact, capacity factors are typically at least 80% and as high as 96%.
According to the US Energy Information Administration (EIA), The United States leads the world in the amount of geothermal electricity generation. In 2020, there were geothermal power plants in seven states—California, Nevada, Utah, Hawaii, Oregon, Idaho, and New Mexico. And yet that world-leading production added up to only 0.4% of total U.S. utility-scale electricity generation, with the vast majority in just California, with 70.5% of total US geothermal electricity generation, and Nevada with 24.5%. Geothermal is also an enormously underutilized form of energy globally; according to Solar Reviews, in 2020, geothermal power plants across the world currently deliver just of electricity, with installed geothermal heating capacity a bit higher at 28 GW.
At the same time, Geothermal represents a very cost-effective way to generate electricity. According to the EIA in its 2020 Annual Energy Outlook, the estimated total levelized cost of electricity (LCOE, unweighted) of geothermal, among new dispatchable generation resources entering service in 2025 (with the tax credit)—including ultra-supercritical coal, combined cycle, combustion turbine, advanced nuclear, and biomass—is lowest. LCOE represents the average revenue per unit of electricity generated that would be required to recover the costs of building and operating a generating plant during an assumed financial life and duty cycle. Key inputs to calculating LCOE include capital costs, fuel costs, fixed and variable operations and maintenance (O&M) costs, financing costs, and an assumed utilization rate for each plant type.
It's also very friendly from an environmental point of view. While geothermal plants do emit greenhouse gases, the amounts are a tiny fraction of those from fossil-fueled plants. Moreover, there are no reported cases of water contamination from geothermal sites in the US, This is not to be confused with fracking.
Generating electricity via geothermal isn’t the only untapped potential of the heat under our feet. The US Department of Energy (DoE) says “Enhanced Geothermal Systems (EGS), also known as Engineered Geothermal Systems, hold the potential to power tens of millions of American homes and businesses.” While generating electricity via geothermal to the grid is limited to specific geographical locations, EGS “requires improving the natural permeability of rock. Rocks are permeable due to minute fractures and pore spaces between mineral grains. Injected water is heated by contact with the rock and returns to the surface through production wells, as in naturally occurring hydrothermal systems. EGS are reservoirs created to improve the economics of resources without adequate water and/or permeability.”
Above all, the untapped potential of geothermal in the U.S. and worldwide is significant, even gargantuan. According to POWER Magazine, “(in) a report released in 2019 by the U.S. Department of Energy, geothermal electricity generation could increase more than 26-fold by 2050—reaching 60 GW of installed capacity.” The key, according to POWER, is advanced drilling techniques, and cites Quaise Energy, “a company working to develop enabling technologies needed to expand geothermal on a global scale, (which) claims as much as 30 TW of geothermal energy could be added around the world by 2050.”
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