clean energy – Treehouse Writers

Geothermal energy has huge potential to generate clean power – including from used oil and gas wells

The world’s largest geothermal power station is under construction in Utah.
Business Wire via AP

Moones Alamooti, University of North Dakota

As energy use rises and the planet warms, you might have dreamed of an energy source that works 24/7, rain or shine, quietly powering homes, industries and even entire cities without the ups and downs of solar or wind – and with little contribution to climate change.

The promise of new engineering techniques for geothermal energy – heat from the Earth itself – has attracted rising levels of investment to this reliable, low-emission power source that can provide continuous electricity almost anywhere on the planet. That includes ways to harness geothermal energy from idle or abandoned oil and gas wells. In the first quarter of 2025, North American geothermal installations attracted US$1.7 billion in public funding – compared with $2 billion for all of 2024, which itself was a significant increase from previous years, according to an industry analysis from consulting firm Wood Mackenzie.

As an exploration geophysicist and energy engineer, I’ve studied geothermal systems’ resource potential and operational trade-offs firsthand. From the investment and technological advances I’m seeing, I believe geothermal energy is poised to become a significant contributor to the energy mix in the U.S. and around the world, especially when integrated with other renewable sources.

A May 2025 assessment by the U.S. Geological Survey found that geothermal sources just in the Great Basin, a region that encompasses Nevada and parts of neighboring states, have the potential to meet as much as 10% of the electricity demand of the whole nation – and even more as technology to harness geothermal energy advances. And the International Energy Agency estimates that by 2050, geothermal energy could provide as much as 15% of the world’s electricity needs.

Two people stand near a large container of shucked corn while steam billows from a pool of water behind them. — For generations, Maori people in New Zealand, and other people elsewhere around the world, have made use of the Earth’s heat, as in hot springs, where these people are cooking food in the hot water.
Wolfgang Kaehler/LightRocket via Getty Images

Why geothermal energy is unique

Geothermal energy taps into heat beneath the Earth’s surface to generate electricity or provide direct heating. Unlike solar or wind, it never stops. It runs around the clock, providing consistent, reliable power with closed-loop water systems and few emissions.

Geothermal is capable of providing significant quantities of energy. For instance, Fervo Energy’s Cape Station project in Utah is reportedly on track to deliver 100 megawatts of baseload, carbon-free geothermal power by 2026. That’s less than the amount of power generated by the average coal plant in the U.S., but more than the average natural gas plant produces.

But the project, estimated to cost $1.1 billion, is not complete. When complete in 2028, the station is projected to deliver 500 megawatts of electricity. That amount is 100 megawatts more than its original goal without additional drilling, thanks to various technical improvements since the project broke ground.

And geothermal energy is becoming economically competitive. By 2035, according to the International Energy Agency, technical advances could mean energy from enhanced geothermal systems could cost as little as $50 per megawatt-hour, a price competitive with other renewable sources.

Types of geothermal energy

There are several ways to get energy from deep within the Earth.

Hydrothermal systems tap into underground hot water and steam to generate electricity. These resources are concentrated in geologically active areas where heat, water and permeable rock naturally coincide. In the U.S., that’s generally California, Nevada and Utah. Internationally, most hydrothermal energy is in Iceland and the Philippines.

Some hydrothermal facilities, such as Larderello in Italy, have operated for over a century, proving the technology’s long-term viability. Others in New Zealand and the U.S. have been running since the late 1950s and early 1960s.

A large yellow vehicle with a tall tower on it stands in front of a house. — A drilling rig sits outside a home in White Plains, N.Y., where a geothermal heat pump is being installed.
AP Photo/Julia Nikhinson

Enhanced geothermal systems effectively create electricity-generating hydrothermal processes just about anywhere on the planet. In places where there is not enough water in the ground or where the rock is too dense to move heat naturally, these installations drill deep holes and inject fluid into the hot rocks, creating new fractures and opening existing ones, much like hydraulic fracturing for oil and gas production.

A system like this uses more than one well. In one, it pumps cold water down, which collects heat from the rocks and then is pumped back up through another well, where the heat drives turbines. In recent years, academic and corporate research has dramatically improved drilling speed and lowered costs.

Ground source heat pumps do not require drilling holes as deep, but instead take advantage of the fact that the Earth’s temperature is relatively stable just below the surface, even just 6 or 8 feet down (1.8 to 2.4 meters) – and it’s hotter hundreds of feet lower.

These systems don’t generate electricity but rather circulate fluid in underground pipes, exchanging heat with the soil, extracting warmth from the ground in winter and transferring warmth to the ground in summer. These systems are similar but more efficient than air-source heat pumps, sometimes called minisplits, which are becoming widespread across the U.S. for heating and cooling. Geothermal heat pump systems can serve individual homes, commercial buildings and even neighborhood or business developments.

Direct-use applications also don’t generate electricity but rather use the geothermal heat directly. Farmers heat greenhouses and dry crops; aquaculture facilities maintain optimal water temperatures; industrial operations use the heat to dehydrate food, cure concrete or other energy-intensive processes. Worldwide, these applications now deliver over 100,000 megawatts of thermal capacity. Some geothermal fluids contain valuable minerals; lithium concentrations in the groundwater of California’s Salton Sea region could potentially supply battery manufacturers. Federal judges are reviewing a proposal to do just that, as well as legal challenges to it.

Researchers are finding new ways to use geothermal resources, too. Some are using underground rock formations to store energy as heat when consumer demand is low and use it to produce electricity when demand rises.

Some geothermal power stations can adjust their output to meet demand, rather than running continuously at maximum capacity.

Geothermal sources are also making other renewable-energy projects more effective. Pairing geothermal energy with solar and wind resources and battery storage are increasing the reliability of above-ground renewable power in Texas, among other places.

And geothermal energy can power clean hydrogen production as well as energy-intensive efforts to physically remove carbon dioxide from the atmosphere, as is happening in Iceland.

A diagram shows pipes extending down from the surface of the ground, pushing cold water into hot rocks below, and drawing hot water back up. — Enhanced geothermal systems can be built almost anywhere and can take advantage of existing wells to save the time and money of drilling new holes deep into the ground.
U.S. Geological Survey

Geothermal potential in the US and worldwide

Currently, the U.S. has about 3.9 gigawatts of installed geothermal capacity, mostly in the West. That’s about 0.4% of current U.S. energy production, but the amount of available energy is much larger, according to federal and international engineering assessments.

And converting abandoned oil and gas wells for enhanced geothermal systems could significantly increase the amount of energy available and its geographic spread.

One example is happening in Beaver County, in the southwestern part of Utah. Once a struggling rural community, it now hosts multiple geothermal plants that are being developed to both demonstrate the potential and to supply electricity to customers as far away as California.

Those projects include repurposing idle oil or gas wells, which is relatively straightforward: Engineers identify wells that reach deep, hot rock formations and circulate water or another fluid in a closed loop to capture heat to generate electricity or provide direct heating. This method does not require drilling new wells, which significantly reduces setup costs and environmental disruption and accelerates deployment.

There are as many as 4 million abandoned oil and gas wells across the U.S., some of which could shift from being fossil fuel infrastructure into opportunities for clean energy.

Challenges and trade-offs

Geothermal energy is not without technical, environmental and economic hurdles.

Drilling is expensive, and conventional systems need specific geological conditions. Enhanced systems, using hydraulic fracturing, risk causing earthquakes.

Overall emissions are low from geothermal systems, though the systems can release hydrogen sulfide, a corrosive gas that is toxic to humans and can contribute to respiratory irritation. But modern geothermal plants use abatement systems that can capture up to 99.9% of hydrogen sulfide before it enters the atmosphere.

And the systems do use water, though closed-loop systems can minimize consumption.

Building geothermal power stations does require significant investment, but its ability to deliver energy over the long term can offset many of these costs. Projects like those undertaken by Fervo Energy show that government subsidies are no longer necessary for a project to get funded, built and begin generating energy.

Despite its challenges, geothermal energy’s reliability, low emissions and scalability make it a vital complement to solar and wind – and a cornerstone of a stable, low-carbon energy future.

Moones Alamooti, Assistant Professor of Energy and Petroleum Engineering, University of North Dakota

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Continue reading “Reprint: New (Green!) Energy From Old Gas Wells”…

This article is reprinted from The Conversation.

California farmers identify a hot new cash crop: Solar power

This dairy farm in California’s Central Valley has installed solar panels on a portion of its land.
George Rose/Getty Images

Jacob Stid, Michigan State University; Annick Anctil, Michigan State University, and Anthony Kendall, Michigan State University

Imagine that you own a small, 20-acre farm in California’s Central Valley. You and your family have cultivated this land for decades, but drought, increasing costs and decreasing water availability are making each year more difficult.

Now imagine that a solar-electricity developer approaches you and presents three options:

You can lease the developer 10 acres of otherwise productive cropland, on which the developer will build an array of solar panels and sell electricity to the local power company.
You can select 1 or 2 acres of your land on which to build and operate your own solar array, using some electricity for your farm and selling the rest to the utility.
Or you can keep going as you have been, hoping your farm can somehow survive.

Thousands of farmers across the country, including in the Central Valley, are choosing one of the first two options. A 2022 survey by the U.S. Department of Agriculture found that roughly 117,000 U.S. farm operations have some type of solar device. Our own work has identified over 6,500 solar arrays currently located on U.S. farmland.

Our study of nearly 1,000 solar arrays built on 10,000 acres of the Central Valley over the past two decades found that solar power and farming are complementing each other in farmers’ business operations. As a result, farmers are making and saving more money while using less water – helping them keep their land and livelihood.

A hotter, drier and more built-up future

Perhaps nowhere in the U.S. is farmland more valuable or more productive than California’s Central Valley. The region grows a vast array of crops, including nearly all of the nation’s production of almonds, olives and sweet rice. Using less than 1% of all farmland in the country, the Central Valley supplies a quarter of the nation’s food, including 40% of its fruits, nuts and other fresh foods.

The food, fuel and fiber that these farms produce are a bedrock of the nation’s economy, food system and way of life.

But decades of intense cultivation, urban development and climate change are squeezing farmers. Water is limited, and getting more so: A state law passed in 2014 requires farmers to further reduce their water usage by the mid-2040s.

Workers on farmland with mountains in the background. — California’s Central Valley is some of the most productive cropland in the country.
Citizen of the Planet/UCG/Universal Images Group via Getty Images

The trade-offs of installing solar on agricultural land

When the solar arrays we studied were installed, California state solar energy policy and incentives gave farm landowners new ways to diversify their income by either leasing their land for solar arrays or building their own.

There was an obvious trade-off: Turning land used for crops to land used for solar usually means losing agricultural production. We estimated that over the 25-year life of the solar arrays, this land would have produced enough food to feed 86,000 people a year, assuming they eat 2,000 calories a day.

There was an obvious benefit, too, of clean energy: These arrays produced enough renewable electricity to power 470,000 U.S. households every year.

But the result we were hoping to identify and measure was the economic effect of shifting that land from agricultural farming to solar farming. We found that farmers who installed solar were dramatically better off than those who did not.

They were better off in two ways, the first being financially. All the farmers, whether they owned their own arrays or leased their land to others, saved money on seeds, fertilizer and other costs associated with growing and harvesting crops. They also earned money from leasing the land, offsetting farm energy bills, and selling their excess electricity.

Farmers who owned their own arrays had to pay for the panels, equipment and installation, and maintenance. But even after covering those costs, their savings and earnings added up to US$50,000 per acre of profits every year, 25 times the amount they would have earned by planting that acre.

Farmers who leased their land made much less money but still avoided costs for irrigation water and operations on that part of their farm, gaining $1,100 per acre per year – with no up-front costs.

The farmers also conserved water, which in turn supported compliance with the state’s Sustainable Groundwater Management Act water use reduction requirements. Most of the solar arrays were installed on land that had previously been irrigated. We calculated that turning off irrigation on this land saved enough water every year to supply about 27 million people with drinking water or irrigate 7,500 acres of orchards. Following solar array installation, some farmers also fallowed surrounding land, perhaps enabled by the new stable income stream, which further reduced water use.

A view of farmland with irrigation sprinklers spraying widely. — Irrigation is key to cropland productivity in California’s Central Valley. Covering some land with solar panels eliminates the need for irrigation of that area, saving water for other uses elsewhere.
Citizen of the Planet/UCG/Universal Images Group via Getty Images

Changes to food and energy production

Farmers in the Central Valley and elsewhere are now cultivating both food and energy. This shift can offer long-term security for farmland owners, particularly for those who install and run their own arrays.

Recent estimates suggest that converting between 1.1% and 2.4% of the country’s farmland to solar arrays would, along with other clean energy sources, generate enough electricity to eliminate the nation’s need for fossil fuel power plants.

Though many crops are part of a global market that can adjust to changes in supply, losing this farmland could affect the availability of some crops. Fortunately, farmers and landowners are finding new ways to protect farmland and food security while supporting clean energy.

One such approach is agrivoltaics, where farmers install solar designed for grazing livestock or growing crops beneath the panels. Solar can also be sited on less productive farmland or on farmland that is used for biofuels rather than food production.

Even in these areas, arrays can be designed and managed to benefit local agriculture and natural ecosystems. With thoughtful design, siting and management, solar can give back to the land and the ecosystems it touches.

Farms are much more than the land they occupy and the goods they produce. Farms are run by people with families, whose well-being depends on essential and variable resources such as water, fertilizer, fuel, electricity and crop sales. Farmers often borrow money during the planting season in hopes of making enough at harvest time to pay off the debt and keep a little profit.

Installing solar on their land can give farmers a diversified income, help them save water, and reduce the risk of bad years. That can make solar an asset to farming, not a threat to the food supply.

Jacob Stid, Ph.D. student in Hydrogeology, Michigan State University; Annick Anctil, Associate Professor of Civil and Environmental Engineering, Michigan State University, and Anthony Kendall, Professor of Earth and Environmental Sciences, Michigan State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Continue reading “Reprint: California Farms Solar Power”…