Hades’ Gates: part 1

31Aug07

Did you know that with each flush of the toilet you both power your home—and cause earthquakes?

“Say, what?”

Well, it’s a twisty, windy story, but here’s a thumbnail sketch: Rohnert Park, Cotati and Sebastopol wastewater is flushed to Santa Rosa. It’s treated there, then pumped 41 additional miles up into the Mayacamas Mountains east of Geyserville. We call this remote area straddling Sonoma and Lake Counties The Geysers—which, incidentally, they are not.

These misnamed “Geysers” are actually fumaroles. They emit vapors, or fumes—hence fumaroles. They don’t spout water. They do, however, generate more electricity than any geothermal field in the entire world.

Each day 11 million gallons of our treated wastewater (and an additional 8 million gallons from Lake County) is injected into seismically active earth at The Geysers. The wastewater shoots down hundreds of wells, each drilled two miles or so into the earth’s crust.This process is called “recharging.”

No cavernous reservoirs like below. Instead, wastewater is injected into tiny fissures of extremely hot permeable rock. And that’s just what it looks like to the naked eye—solid rock. But it’s not. These hot rocks and attendant gasses vaporize, or “flash” the water, sending it back to the surface in the form of steam. This compressed steam turns turbine blades, producing electricity. Each day enough electricity is generated from our wastewater at The Geysers to serve the needs of the entire North Bay, or put another way, the power produced from “recharging” The Geysers equates to over 60 million barrels of oil each year.

On the flipside—recharging causes earthquakes.

According to the Berkeley Seismological Laboratory: “There were no earthquakes observed in the area of (The Geysers) geothermal field between 1949 and 1975. Starting in 1976 earthquakes were observed in the geothermal field and the rate steadily increased…”

Calpine operates 19 of the 21 powerhouses producing electricity from The Geysers. Their geologists estimate that earthquake frequency has risen 40% since Geyser wastewater injection began. USGS seismologist Dave Oppenheimer notes, “You’re going to have small earthquakes that may not have occurred at a rate that you’re seeing now because your rate of stress change is higher.”

Fortunately, wastewater injection at The Geysers is unlikely to produce anything larger than, oh, say—a magnitude 5 earthquake! Count your lucky stars the geothermal field lies amidst minor fault lines. On the other hand, were The Geysers part of the San Andreas or the Hayward fault regimes…well—we’ll leave that one alone for now.

The really good news is while electricity produced from the Geysers peaked some 20 years ago, we benefit from this energy resource in more than one way.

Remember that proposed nuke on Bodega Head? Don’t need it. And what sounds better to you—44 billion gallons of wastewater producing 850 megawatts of clean renewable energy, or 44 billion gallons of treated wastewater pumped into the Pacific Ocean at one of our pristine beaches every year? What’smore, we have bragging rights in that we live in the very county that produces more geothermal energy than anywhere on the face of the planet.

But there’s more to the story than that.

Filed under: Bay Time Detective, Cotati, Gates of Hell, Mayacamas Mountains, Miwok, Native Americans, North Bay, Penngrove, Pomo, Rohnert Park, San Francisco Bay Area, San Francisco Bay Area History, San Francisco Phax & Phikshun, Santa Rosa, Sonoma County, The Geysers, Wappo, earthquakes, fumaroles, geothermal power, myth, public utilities, renewable energy, spas   |  Leave a Comment