According to a New York Times article, California is under attack from natural forces rising up from below. Perpetual optimism, the chance for big bucks, and discreetly omitted data is fueling a federally funded, multi-million contract to assigned to a private start-up to drill deep holes more than 2 miles into the earth's crust, pump down high pressure water to shatter rock and create a network of fractured veins, then pump in more water, to be naturally heated by the high temperatures of the surrounding bedrock and extracted as high pressure steam to generate electricity.

The Only Problem: In 2006, a company in Basel, Switzerland tried the same method--called enhanced geothermic systems (EGS)--and induced, in a year's time, more than 3,500 earthquakes. Several were above 3.0.

An official a few miles from the Basel drilling site was stunned when he realized the shaking ground beneath his office was directly caused by his company's drilling.

This data was omitted from an MIT report surveying geothermal potential and current technology (the report was already in print, but no addendum was added or issued), and missing from the permit applications and grant requests of the start-up that's been given the go-ahead to drill. In at least one application, the start-up claimed to be “uncertain” about the cause of the Swiss tremors.

In a interview, the founder of the start-up, an expert in geothermal systems, claims the risks can be offset by drilling in areas with minimal fault lines. She did not address the relationship between drilling depth and earthquake triggers (the deeper the drilling the more likely the trigger). Moreover, the founder claims that technological tweaking the method will reduce the implied risks associated with the largely untested model.

photo: Jennifer Boyer.(fair use)

Nor in other interviews, does she offer a caveat widely supported by the data: the deeper the drilling the greater the propensity for engineered earthquakes.

Her company plans to drill down 2 miles in an area already experiencing tremors as the result of more traditional geothermal projects. In fact, over 3,000 small tremors have been directly linked and documented to drilling done for the current California projects.

A lead official in California directly responsible for permitting geothermal projects admitted when he asked that he was unaware the Basel project triggered more than 3,500 quakes.

Geothermal energy has huge attractions in an environment seeking green power. It is renewable and emission free. It is widely available if EGS can be developed efficiently and safely.

Several articles available on the web only cite capital risks: EGS is one of the most capital intensive green energy technologies, but has low operating costs. These studies and several interviews focus on the captial risks of production and the potential for cost efficiencies by reducing the cost curve as the technology advances.

These articles when they assess risk omit any mention of the structural risks of earthquakes. They point to EGS' small foot print and around the clock performance.

The real question is whether man-made systems can duplicate nature, without the dangers of minor or major earthquakes, triggered and lasting for years caused by shifts of the deliberately fractured rock bed.

“Pore pressure,” fracture creep, excessive stress beyond support levels, low fluid content, low rock permeability, high content of undesirable gases, and tectonically active areas increase risk factors.

But why is the risk of seismic activity not a part of the discussion?