How Much Power Does Geothermal Make In Satisfactory?

Geothermal energy is thermal energy generated and stored in the Earth (1). It is a renewable energy source that utilizes the heat within the earth to produce electricity and provide heating and cooling. Geothermal resources are reservoirs of hot water found a few miles or more below the Earth’s surface that can be tapped for energy production (1).

In the United States, geothermal power capacity has grown steadily over the past decade. As of 2019, the installed geothermal power capacity in the US was over 3,700 megawatts (MW), providing approximately 0.4% of total utility-scale electricity generation (2). There is increasing interest in geothermal energy as a clean, reliable, and flexible source of renewable power. With advancements in technologies, enhanced geothermal systems, and growing investment, there is potential for significant growth in US geothermal power generation.

(1) https://www.energy.gov/eere/geothermal/geothermal-basics

(2) https://www.eia.gov/energyexplained/geothermal/

Geothermal Power Basics

Geothermal power plants harness heat from underground reservoirs to generate electricity. There are three types of geothermal resources used for electricity production:

• Hydrothermal resources contain hot water and steam underground. The steam from hydrothermal reservoirs can be piped directly to drive turbines and generate electricity.
• Enhanced geothermal systems (EGS) involve injecting fluid into hot rock reservoirs to produce steam. The injected fluid absorbs heat from the rocks and returns to the surface as hot water and steam to drive turbines.
• Geopressured resources contain hot briny water under high pressure. The hot water can be used to make steam to drive turbines.

In a conventional geothermal power plant, wells are drilled into a hydrothermal reservoir. Hot water and steam are brought up through production wells to the power plant where they turn turbines attached to electricity generators. The steam condenses into water and is injected back down an injection well into the reservoir to be reheated.^[1]

[1] https://www.energy.gov/eere/geothermal/electricity-generation

Geothermal Power Production Capacity

The United States is the world leader in geothermal power capacity. According to the U.S. Energy Information Administration, the installed geothermal power capacity in the United States was over 3,600 megawatts (MW) as of 2019, accounting for approximately 25% of global geothermal power capacity [1]. U.S. geothermal power capacity has seen steady growth since the 1960s. In 1960, total U.S. geothermal capacity stood at just 127 MW. By 1980, this had grown to over 1,000 MW, and by 2000, capacity exceeded 2,500 MW [2]. The growth rate accelerated in the late 2000s and early 2010s, with over 600 MW of new geothermal power coming online between 2010 and 2013 [3]. As of 2021, geothermal power accounted for 0.4% of total U.S. utility-scale electricity generation.

Top Geothermal Power Producing States

The top geothermal power producing states in the U.S. are:

1. California – The state leads the nation in geothermal power generation with over 2,700 MW of installed capacity, accounting for around 40% of total U.S. geothermal power. Most of California’s geothermal plants are located in the northern part of the state near the Geysers geothermal field north of San Francisco. [1]
2. Nevada – Nevada has around 1,000 MW of installed geothermal capacity, accounting for about 16% of the U.S. total. Major geothermal plants are located near Reno and Elko. [2]
3. Utah – With over 400 MW of geothermal power capacity, Utah ranks third in the U.S. Most of the state’s geothermal plants are located near Salt Lake City and account for about 5% of total U.S. geothermal generation. [3]
4. Hawaii – Hawaii has around 200 MW of geothermal power capacity from plants located on the Big Island, accounting for about 4% of U.S. geothermal generation.
5. Idaho – Idaho has around 150 MW of geothermal capacity, with plants located near Twin Falls accounting for about 2% of total U.S. geothermal power.

Environmental Benefits

Geothermal energy is considered a clean, renewable energy source with significantly lower emissions compared to fossil fuels like coal, oil, and natural gas. According to the U.S. Energy Information Administration, geothermal power plants emit 97% less acid rain-causing sulfur compounds and about 99% less carbon dioxide than fossil fuel power plants.

Because geothermal plants do not burn fossil fuels to generate electricity, they produce near-zero emissions. The geothermal water and steam that is used to spin turbine generators contains trace amounts of gases like carbon dioxide, hydrogen sulfide, ammonia, and methane. But these are negligible emissions, especially when compared to coal and natural gas power plants. The International Geothermal Association estimates geothermal electricity generation emits just 4-7% of the carbon dioxide per kWh that coal-fired plants emit.

Overall, geothermal is an environmentally-friendly energy source that helps reduce air pollution and carbon emissions significantly compared to conventional power generation. Using geothermal energy over fossil fuels provides major environmental benefits.

Economic Benefits

Geothermal energy production provides significant economic benefits in terms of job creation and revenue generation. According to a 2005 report by the National Renewable Energy Laboratory, the geothermal industry directly employed 5,000-6,000 workers in 2005, with projections to add another 1,000 jobs. The geothermal industry generates billions in revenue through the sale of electricity. In 2021 alone, geothermal power plants in the U.S. generated over 15 billion kWh, representing over $1.5 billion in revenue.

The geothermal industry has seen steady growth over the past decade. According to the Geothermal Energy Association’s 2022 U.S. Geothermal Power Production and Development Update, geothermal power capacity grew at an annual rate of 3.7% over the past 5 years. With continued growth projected, the industry expects to generate over 26,000 jobs in the U.S. by 2030. Geothermal’s economic contributions are expected to be substantial as more projects come online.

Challenges

While geothermal energy has many benefits, it also comes with some notable challenges that limit its wider adoption. Three major challenges facing geothermal power are high upfront costs, suitable locations, and reservoir depletion over time.

Constructing a geothermal power plant requires significant upfront capital investment. According to a report by the Union of Concerned Scientists, a typical geothermal power plant costs between $2-5 million per megawatt (MW) of generating capacity to build. This is significantly more expensive than other renewable energy sources like wind and solar. While geothermal plants have relatively low operating costs, the high initial investment can be a major barrier.

Another challenge is that geothermal power is only feasible in locations with optimal geothermal resources. As the RFF Organization notes, geothermal energy production is largely limited to tectonically active areas like western states, Hawaii, Alaska, and parts of the Caribbean. Most other areas lack the underground heat and permeability needed to produce electricity. This limits the broader expansion of geothermal nationwide.

Finally, overdrawing heat and fluids from geothermal reservoirs can lead to depletion effects over time. According to the Lafayette College report, geothermal fields in some locations have experienced up to a 30% drop in generating capacity over a 25 year period. Careful reservoir management is needed to ensure long-term sustainability.

Latest Technologies

There are several promising new technologies emerging that could significantly advance geothermal energy production in the future. According to the U.S. Department of Energy, next-generation geothermal technologies like enhanced geothermal systems (EGS) could provide up to 120 gigawatts of capacity in the U.S. by 2050 (source). EGS involves injecting fluid into deep hot rock formations to create new fractures and permeability, allowing geothermal resources to be developed in areas without natural convective hydrothermal resources.

The Department of Energy is currently funding over 80 projects to advance EGS, including research into new drilling technologies that allow for deeper, more directional wells (source). Other innovations like using carbon dioxide instead of water as the working fluid in EGS systems could boost productivity while reducing greenhouse gas emissions. There is also active research into hybrid geothermal systems that combine geothermal with solar thermal or biomass energy production.

With continued technology improvements and research, the geothermal resource base could expand dramatically in the coming decades. This could position geothermal to become a major clean electricity source alongside solar and wind.

Future Outlook

The future outlook for geothermal power is positive, with predictions of significant growth. The U.S. Department of Energy has set a goal to expand geothermal power production in the United States to 60 gigawatts by 2050, a 2600% increase from 2015 levels. This ambitious target demonstrates the enormous untapped potential of geothermal energy. With enhanced technologies like improved drilling techniques and advanced power plant designs, even more widespread utilization of geothermal resources will be possible. New methods like enhanced geothermal systems (EGS) could enable geothermal power production almost anywhere by artificially creating reservoirs where none exist naturally. As research and development in the geothermal industry progresses, the costs are projected to decrease, further boosting growth projections. The global market for geothermal power is forecast to expand at a compound annual growth rate of 3.4% from 2022-2030, reaching an estimated $6.8 billion by the end of the decade.

Conclusions

In summary, geothermal power shows great promise as an important renewable energy source. While geothermal currently only accounts for a small portion of US electricity production, there is significant potential for growth with further investment and technology improvements. Key geothermal states like California, Nevada, and Utah are leading the way, but abundant geothermal resources exist across the Western US.

Geothermal stands out for its baseload capacity and hybrid pairing abilities with other renewables. As an indigenous and renewable resource, geothermal can provide stable, low-emission energy production. Enhanced geothermal systems and new technologies create possibilities to unlock even more geothermal potential. Although startup costs remain high, geothermal’s long-term economics are competitive. With the right policies and innovations, geothermal seems poised to play a sizable role in the nation’s renewable energy future.