Santa Rosa (treated) waste water fueling geothermal reservoirs at the Geysers
Calpine Unit 3, Sonoma Power Plant. Source: Loettahuro (Panoramio.com)
Alexander Richter
14 Sep 2010
The county of Santa Rosa/ California is providing treated waste water for refueling the geothermal reservoirs at The Geysers at plants of Calpine.
A rather interesting news piece, describes how the county of Santa Rosa uses waste water for use in geothermal power generation.
“The process (of using waste water from businesses and homes) has reached such a level of such automation and dependability, many people in and around Santa Rosa don’t give it a thought anymore. When it first came online in 2004, however, the new system of wastewater treatment was truly something to talk about for a region that was running out of options to get rid of its waste.
It helped that the system also gave the city a perpetual supply of self-replenishing energy.
“We had been looking since 1985 for a solution to not have to discharge (waste) to the river,” said Dan Carlson with the Santa Rosa Utilities Department.
Carlson said it was to the point where the Russian River was becoming tapped out as a viable destination for the city’s treated wastewater.
In the nearby Mount St. Helena region, the Calpine Corporation had problems, too. Their geothermal power operation was running short on mother nature’s naturally heated water supply, which boils from beneath the surface in the Mayacamas Mountains, known by most as The Geysers.
“There’s only so much natural water that exists (under The Geysers), so we have to get it from other sources,” said Calpine General Manager Larry Sessions.
His company, along with the Santa Rosa Utilities Department, were two organizations with unique environmental issues. Their respective problems provided solutions for the other.
“We had a resource that we had too much of,” said Carlson, talking about wastewater. “And (Calpine) had a resource need” for that wastewater.
To transfer that resource to Calpine, the city of Santa Rosa installed 40 miles of pipes to run from the plant, up the nearby mountain, to a network of 15 geothermal power plants. There, the treated wastewater is converted to electricity.
“Last year, we used every drop (of wastewater),” said Carlson. “We did not discharge any water to the Russian River.”
“With The Geysers, we can use (the wastewater) 24 hours a day, continuously, so it’s perfect,” said Sessions. “(Santa Rosa) needs to get rid of it continuously, we need to use it continuously.”
Sessions said the company’s steam turbines can create electricity from wast water, the same way they do with water from beneath the surface.
In short, whatever comes from the toilets, showers and sinks of Santa Rosa ultimately helps keep the lights on.
“This project was a win-win,” said Carlson. “That term is way overused, but it was a win for the city, and a win for a private company.”
With contributions from Sonoma and Lake counties, Calpine says they have all the water they could possibly need to run their operation, regardless of how much naturally heated water is underground.”
Source: News 10
