Tour the Geysers geothermal field
On an overcast morning early last month, a group of 15 people met in tiny Middletown in Lake County for a unique experience — a tour of the rarity that is the power-producing Geysers geothermal field.
The Geysers, covering 45 miles within the Mayacamas Mountains, is home to the largest complex of geothermal power plants on Earth.
Calpine Corporation, which hosts these tours, is the biggest geothermal power producer in the United States. Calpine owns 13 geothermal power plants at The Geysers and can generate up to 725 megawatts of energy around the clock.
The tours, which include touring a Calpine power plant, will restart in April, but they do fill up. So be advised — on Jan. 3, tickets will open for the 2022 tours.
Our tour group was met at the visitor center by Danielle Matthews Seperas, Calpine’s director of government and community affairs, and Tim Conant, Calpine geothermal mechanical engineer. We boarded the small tour bus, with borrowed hard hats in hand, and headed up Highway 175.
Just past the village of Anderson Springs, we started uphill through hairpin turns to The Geysers geothermal field. The mountains retain much of their magnificent beauty and grandeur, with mixed evergreen forests and California chaparral and woodland, after making a comeback from recent wildfires such as 2015’s Valley fire that burned more than 76,000 acres and nearly 2,000 structures and the Kincade fire in 2019 that was similarly devastating.
Our first stop was the Sonoma Overlook. The dips, peaks and dramatic crags of the Mayacamas Mountains are more pronounced after the Valley fire exposed so much of the mountains’ countenance.
“On clear days, you can see the ocean from here,” Seperas said.
“This stop is also known as ‘Little Alaska,’ since it gets so cold and windy in winter,” Conant added. We were driving over 24-inch effluent pipes that originated in Santa Rosa, he said. A maze of monster-size 48-inch pipes, made of carbon steel, ran up the side of the road.
Next up was the Burned Mountain fumaroles, openings in the Earth’s crust that emit steam and gases. Here we were reminded that Earth has a fire in its belly — water meets the super-heated rock below the surface, and steam rises up through the fumaroles and all along both sides of the road.
It was surprising to learn that a perennial native grass, geysers dicanthelium, thrives in the sulfuric, heated environment here. This area proves too hot for most plants to handle; however, this hardy grass has found a way to make use of the hot steam vents.
After the grass seeds have dispersed, the plants germinate at high temperatures. Other flora that have evolved to thrive in the greenish serpentine and red volcanic rock soils of The Geysers’ ridges include glandular western flax, snow mountain buckwheat and Morrison’s jewel flower, which pay no heed to the low calcium and high heavy metals of these unique soils.
A history of electricity
The first electricity was generated at The Geysers in the 1920s, when John C. Grant used a small steam-engine generator to produce the electricity. He acquired a lease for The Geysers Resort and hoped to generate electrical power from steam to sell to Healdsburg and Cloverdale.
Beginning in the 1950s, the rocky outcrops at The Geysers sported a crazy-quilt of steam-drilling companies. Today, the Calpine Corporation is the predominant drilling company, with about 300 employees.
During the 1970s and 1980s, the water in Earth’s reservoir proved to have limits, forcing out some drilling companies. Steam pressure to the power plants decreased, as more steam was directed to the power plants than could be replaced in The Geysers natural reservoirs.
In a win-win to allow for a continued abundance of steam to flow and to solve Lake and Sonoma counties’ wastewater dilemmas, two large-scale wastewater injection projects were created. In 1990, Geysers operators, Lake County and the California Energy Commission collaborated to identify a source of wastewater from Lake County. The project is called the Southeast Geysers Effluent Pipeline and now includes 40 miles of pipeline to deliver effluent to The Geysers.
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