Biding its time beneath our feet is enough heat to power the entire state of California. But that's nothing. According to a 2008 estimate from the US Geological Survey, there may be enough sub-surface energy in the West alone to meet roughly 70 percent of the nation's electricity needs. Other projections have placed that figure far higher, exceeding the sum of all energy consumed in the United States.
Lofty promises also have been made about solar and wind, but there's a vital difference: Geothermal is reliable. Unlike solar and wind power, which depend on the weather and thus require backup storage or natural gas plants to be effective, geothermal can single-handedly displace fossil fuels.
Development of geothermal energy also produces minimal environmental impacts, further distinguishing it from large-scale solar, which can harm desert species, and wind turbines, which kill birds and bats. New closed-loop geothermal plants operate with essentially zero water use and no emissions but steam, and the technology is far safer than nuclear fission. Renewable, carbon-free geothermal is about as free of trade-offs as energy gets, and as a resource is nearly inexhaustible.
It can also be one of the cheapest sources of energy available. A January 2010 report by the California Energy Commission comparing costs of electricity generation for new plants in the state — including capital expenses, financing, insurance, taxes, fuel, and operations and maintenance — identified geothermal as among the most affordable: cheaper than solar, natural gas, and biomass, similar to coal, and beaten only by wind and hydropower.
In short, geothermal could be the answer to all of our energy needs — if only we could get to it.
Although the geothermal industry in the United States is nearly fifty years old, cumulative energy production remains relatively small: a total of 3,200 megawatts, equivalent to three nuclear reactors or six coal plants. That figure continues to grow, slowly — 450 megawatts of new power have come online in the last seven years, including 91 megawatts from five projects since the beginning of 2011. By comparison, the US solar industry, which is approximately the same age, added 500 megawatts in the first three months of 2012 alone.
Despite its obvious benefits, geothermal energy faces a suite of external and internal challenges. These include the up-front expense of locating and harnessing geothermal resources, the lack of effective government incentives, and the recent decline in natural gas prices. All three are stifling new exploration and development today, and threatening geothermal's ability to fulfill its promise tomorrow.
Vast quantities of potential geothermal power are currently available in known locations using existing technologies, just waiting to be tapped: according to the US Geological Survey, as much as 16,000 megawatts, or 16 gigawatts. That's the low-hanging fruit. Another 8 to 73 gigawatts may exist in undiscovered traditional systems.
New technologies and drilling techniques being developed now, however, will offer access to an exponentially larger amount of geothermal power. Estimates range from the Department of Energy's low-end 100 gigawatts to the upper range of the US Geological Survey's projections at an incredible 725 gigawatts, not including anything east of Colorado, which has yet to be adequately mapped. The United States' total existing energy production capacity is around 1,100 gigawatts.
Geothermal's eye-popping prospects have caught the attention of the federal government and the high-tech sector. In 2009, the Obama administration earmarked $341 million in stimulus funds to support geothermal development. Although those funds are not yet exhausted, the energy department's Geothermal Technologies Program has requested that its annual financial allotment be nearly doubled next year. The Lawrence Berkeley National Lab, National Renewable Energy Laboratory, and United States Geological Survey are all also engaged in geothermal energy research. And in 2008, Google's philanthropic arm placed a bet of its own, to the tune of more than $10 million.
Nonetheless, the geothermal industry is only cautiously optimistic, forecasting moderate growth in the coming years but loath to make any promises. As one official with the Department of Energy's geothermal program summed up the industry's short-term outlook, "Our goal is that when people discuss renewables like wind and solar, they mention geothermal in the same sentence."
The rocky trajectory of the geothermal industry in the United States, from its hopeful beginnings in the early 1960s through decades of ups and downs to its expansive yet elusive potential today, can be traced through a huge geothermal field right here in Northern California. Straddling Sonoma and Lake counties in a mountainous, largely undeveloped area south of Clear Lake, the 45-square-mile geothermal field known as The Geysers houses the world's largest complex of geothermal plants. It currently produces around 900 megawatts of power, nearly a fifth of California's clean-energy portfolio.
Fifteen of the field's eighteen plants belong to Houston power company Calpine, which was founded in San Jose in 1984 and has a 23-year history at The Geysers. As the company grapples with mistakes in The Geysers' past, looks toward near-term expansion, and works to develop the next generation of geothermal energy, it mirrors the path of the industry as a whole. Its success in the coming years will help determine if large-scale geothermal power will become a panacea or simply another science-fiction pipe dream.
The first thing any visitor to The Geysers notices is its sheer remoteness. The drive from Calpine's visitor center in nearby Middletown to some of the more distant drilling platforms can be thirty miles or more. Newcomers sometimes arrive expecting to pull up to a single massive power plant with huge volumes of steam billowing into the blue sky, said Danielle Seperas, Calpine's manager of Government and Community Affairs. They're often disappointed.