50 years of green energy

For the past 50 years, long before “renewable” became a
buzzword, renewable geothermal energy from The Geysers has powered
the North Bay.
“Since 1960, we’ve been producing green energy for the
community,” said Calpine General Manager of Operation Larry
Sessions. “The Geysers have been here for a lot longer than green
has been a cool term.”
The Geysers, alas, are not actually geysers. They are
technically fumaroles, but the misnomer has been around for
approximately 150 years and isn’t likely to disappear anytime soon.
Geysers, like Old Faithful in Yellowstone, spew water and steam;
fumaroles spew only steam.
Regardless of their scientific classification, The Geysers are
the world’s single largest geothermal resource developed for
electrical generation. They provide California with 20 percent of
its total renewable energy portfolio, and generate enough
electricity to power 60 percent of all energy needs from the Golden
Gate Bridge to the Oregon border.
The Geysers have been operated by a series of different energy
companies, including PG&E. Today, Calpine manages the vast
majority of generation sites within the remote valley that sits at
the border of Lake and Sonoma Counties. Calpine generates 725
megawatts of electricity around the clock, and sells most of that
power to PG&E.
More than 400 producing wells, 100 injection wells, and 15 plant
sites are tucked into 45 square miles of wild valley land riddled
with rattlesnakes, cougars, and deer. For 350 employees and 100
regular contractors, this valley is their home away from home.
But while Calpine employees speak of The Geysers fondly, to
visitors, the landscape can be a bit shocking.
Where creeks intersect with natural fumaroles, geothermal energy
and escaping steam concoct a witch’s cauldron of bubbling murky
water. In the wall of a canyon where a fire burned through a few
years back, a moonscape is left: no plants have re-grown because
the ground is simply too hot. Instead, mineral deposits of boron
and sulfur crunch underfoot, white and yellow lace against a dark
ash background.
Nearby boulders are warm to the touch no matter the air
temperature, and an algae-rich stream feels like a hot bath. Rich
with dissolved minerals, the basic pH of the stream leaves
fingertips soft after a dip.
Although 80 miles of pipes now stretch across the landscape, The
Geysers are still strikingly similar to a description penned by
nineteenth century journalist Bayard Taylor:
“All vegetation is blasted by the mixture of powerful vapors.
The ground is hot under your feet: you hear the bubbling of boiling
springs, and are half choked by the rank steam that arises from
them,” Taylor wrote.
He continued, “This is the Witches’ Caldron. Its temperature, as
approximately ascertained by Capt. Davidson, is about 500 degrees.
An egg dipped in and taken out is boiled; and were a man to fall
in, he would be reduced to broth in two minutes.”
The drama of the landscape reflects an underlying power. (One
might say it’s almost electric.) The steam that builds up beneath
the earth’s surface can be tapped by wells, which are drilled
between 4,000 and 10,000 feet deep.
The steam rises up into the well head and makes its way through
insulated pipes to a turbine, where it turns a series of wheels to
generate power.
After this process is complete, all gases and liquids intended
for discharge are chemically “scrubbed” to prevent the release of
deep-earth elements into the environment. Some of the scrubbers
actually produce sulfur cakes as waste; the sulfur cakes are then
provided to agricultural companies for the cost of hauling.
“We’re not producing any chemicals that would harm the
environment,” Sessions said. “In fact, it’s our goal to leave the
place cleaner than we found it.” According to Sessions, the
geothermal plants are so carefully monitored that even accidental
outdoor coffee spills are reported to government agencies.
Because steam flows incessantly out of the ground, the plant
provides a constant baseload of energy—unlike wind, solar, or
hydroelectric power, which vary depending on the availability of
their respective natural resources.
However, The Geysers do need recharging to continue to function,
which is why wastewater is piped from Santa Rosa and Lake County
and injected into the ground through infiltration wells.
“In the 80s and 90s, people thought The Geysers were dying, and
that they’d overdeveloped it. What happened was, 75 to 80 percent
of the water we use is dissipated into the atmosphere. If you don’t
recharge, you’re just emptying the tea kettle, so to speak,”
Sessions said.
The “steam” that is sometimes seen rising from The Geysers is
not actually fumarole steam, as many observers think. It’s heat
from the cooling towers forming an inversion layer, which reflects
and warps light. However, water used in the cooling towers does add
considerable moisture to the atmosphere, which can contribute to
cloud cover hovering over the mountains. It can also provide a
helpful buffer against wildfires that occasionally tear through the
valley.
Another common misconception about The Geysers is who,
precisely, is getting the electricity that’s generated.
The electricity market is complicated. Because electric power
transmission along lines is inefficient—that is, the farther the
electricity travels, the more energy is lost along the
way—electricity is always routed to the closest customer.
But while North Bay residents may be receiving power from the
Geysers, someone in Florida might be the one paying for it, to
support green energy and enhance their renewable portfolio—even
though they’ll be receiving electricity from the substation and
power plant closest to their home.
“The funny thing about geothermal is, it’s not a newer
technology. Wind and solar are still really trying to develop, but
they have great marketing campaigns,” Sessions said. “We’re dirt
and rock type people.”
Geothermal might not be as catchy as other renewable energies,
but when it comes to reliability and longevity, it’s solid. Calpine
operates at 99.9 percent availability, which means that they are
only offline one tenth of one percent of the time.
There is room for further development at The Geysers, but with
gas prices low and competition from conventional energy steep,
further exploration can be risky. A two-mile deep well costs about
$8 million, leaving little room for error—a tough sell when the
underground topography of steam pathways isn’t fully
understood.
“It is a really good product,” Sessions said. “But it only
exists in a few places, and if you’re lucky enough to have it in
your backyard, congratulations!”
Congratulations is, perhaps, just the word for the series of
companies that have successfully utilized a natural resource in
Sonoma County’s backyard for the past 50 years.