November 2, 2024

The Geysers of California: The World’s Largest Complex of Power Plants Capturing Subterranean Heat

The steam-driven turbines in this area can create 725 megawatts of electrical energy, which is adequate to power a city the size of San Francisco. The Geysers power plants normally supply the power requirements of Sonoma, Lake, and Mendocino counties, as well as a part of Marin and Napa counties. As of 2018, turbines in the Geysers location produced 50% of Californias geothermal power.
At that time, there were 21 power plants with a total capability of more than 2,000 megawatts. After that, power production began to decrease as the steam reservoir began to tap out.

Found around 8 miles (13 kilometers) northeast of Geyserville, the site is now house to 18 power plants that use steam to drive turbines to generate electrical energy. The white roofing systems of several of the power plants are visible in this natural-color satellite image, which was acquired by the Operational Land Imager (OLI) on Landsat 8 on January 10, 2022.
The steam-driven turbines in this area can produce 725 megawatts of electrical power, which is enough to power a city the size of San Francisco. The Geysers power plants usually provide the power needs of Sonoma, Lake, and Mendocino counties, along with a portion of Marin and Napa counties. Since 2018, turbines in the Geysers area produced 50% of Californias geothermal power.
Geothermal energy is produced by drawing out heat from within the Earth, either through natural steam or extremely warm water. It is a eco-friendly and trusted source of energy. It has the advantage of being available whether the Sun is shining or the wind is blowing.
Three aspects are required to produce geothermal energy: lava close to the surface area, fractured or permeable rock, and fluids that can distribute through the heated rock. At The Geysers, the body of rock that intruded over a million years ago lies just 0.6 miles (1 kilometer) listed below the surface area. Deeper parts, below 1.5 miles (2.5 kilometers), can reach temperatures of 750 ° F (400 ° C).
While most geothermal power plants tap into water reservoirs, according to the U.S. Geological Survey, the Geysers system is among only two vapor-dominated systems in the world. This means the formation produces steam straight, which can be tapped more effectively to produce electrical energy.
At that time, there were 21 power plants with a total capacity of more than 2,000 megawatts. After that, power production began to decline as the steam tank began to tap out.
In the mid-1990s, plant operators relied on a practice called enhanced geothermal systems (EGS) to sustain energy production and extend the life of the field. Water is injected at high pressure to reopen the natural fractures in the rock and allow warm water or steam to flow into the wells. Today, 2 pipelines provide treated wastewater to recharge the tank from Lake County and the city of Santa Rosa.
NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey.

January 10, 2022. Click the image for a wider, high-resolution view.
Warm springs and fumaroles dot this misnamed geothermal field that hosts the worlds largest complex of power plants catching below ground heat.
A big blob of silica-rich lava required its method through Earths crust below the Coast Range of northern California about 1.3 million years back. Today that shallow rock body is still piping hot, and the 45-square-mile (120-square-km) area above it is called The Geysers. It is the worlds largest energy-producing geothermal field.
Although the close-by Clear Lake volcanic field was still erupting as just recently as a couple of thousand years ago, this geothermal field never ever actually had any geysers. The Geysers is a misnomer that came from with 19th-century settlers to the area who misinterpreted the hot springs and fumaroles bubbling and steaming away in the canyon of Big Sulphur Creek. From the mid-19th to the mid-20th century, a popular resort hotel run in the area. Indigenous people of the region have actually checked out the springs given that ancient times.

By Sara E. Pratt, NASA Earth Observatory
September 6, 2022