Digging deep for alternative energy

By Dorothy Ramienski
Internet Editor
FederalNewsRadio

For the first time in 30 years, the U.S. Geological Survey has released estimates on the potential for geothermal power.

USGS says geothermal power could serve as a significant source of electric power generation.

On Friday’s Daily Debrief, hosts Christopher Dorobek and Amy Morris spoke with Colin Williams, project chief of the geothermal project, who explains the report.

What you can take away from this report . . . is that, what we would call the conventional geothermal resources — the resources that are similar to the ones that were evaluated in the 1970’s — those can be significant in the context of the renewable portfolio standards that many states . . . have set for renewable power. They typically are targeting that 10 or 15 or maybe even 25 percent of the state’s electricity should come from renewable energy sources. Conventional geothermal can play a significant role in that.

So, geothermal energy could help states meet their individual goals, but Williams also points to a larger meaning in the document.

In the big picture, we look at the entire U.S. Energy budget. The U.S. currently has an installed electric power capacity of about a million megawatts and it’s expected that that’s going to need to increase by about 300,000 more megawatts in the next 20 years. In that context, geothermal has been something of a marginal player in the past, but if some of these new technologies for extracting geothermal energy from relatively unfractured rock advance, then we believe it can make a significant contribution to the overall nation’s energy mix.

Geothermal power involves getting hot water out of the Earth and using the energy in the heat of that water for a variety of purposes, including electric power generation.

Williams says this is only one of the jobs of the USGS.

As the Geological Survey, we’re responsible for evaluating and assessing all sorts of geological energy resources, whether its coal or oil and gas [and] uranium on one side — or, in the case of renewable energy, geothermal.

The study on geothermal power was conducted now, Williams notes, for a variety of reasons.

The technology has evolved. There are new technologies for getting electric power out of lower temperature geothermal fluids. They used to have to rely on very high-temperature geothermal waters. Now we can get electricity out of what we call moderate-temperature fluids. Also, there are new technologies for improving the way in which we can extract heat from the Earth. In essence, with a classic geothermal system, where you basically rely on having fractures or other space in the rock . . . that allows water to flow very rapidly into a well that produces that geothermal fluid, there are new technologies for helping to improve or even create those flow paths.

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While there are 30 years between this survey and the last one, Williams says USGS plans on conducting geothermal power surveys more frequently from now on.

In this current assessment we have an estimate of the potential for the technology for enhancing the flow paths of the permeability of the rock — which is referred to by the Department of Energy as enhanced geothermal systems — that’s a rapidly evolving technology. So, we’re taking a current snapshot of that [but] we definitely want to look at it again in the next few years and see where the studies have taken us.

Williams also notes that it’s been about 30 years since the U.S. Had it’s last energy crisis. With the price of oil on a seemingly constant rise, he says a lot more attention is now focused on alternative ways to generate power.

Geothermal power has it’s problems, too, however. Williams says it’s fairly difficult to see that deep into the Earth.

A lot of the geothermal we know about has what are called ‘surface manifestations’ — hot springs or geysers — Old Faithful is perhaps the most spectacular example — that of course tell you that there’s something going on there. But there are various geological and geophysical techniques that are employed to try to examine what might be going on under the ground to try to locate these geothermal reservoirs — but that’s actually a technology that, while it’s gone through tremendous advances in the past 30 years, we also need to make significant improvements on it.

The biggest obstacle doesn’t necessarily involve the search process itself; rather, Williams says, it comes down to the difference between hot and cold.

Oil . . . is a very different fluid from water and water is what most of the Earth is filled with — at least in the shell or crust — and so you can employ different ways of recognizing oil and natural gas in the subsurface because it’s fairly distinct from water. With geothermal, we’re looking for the difference between hot water and cold water and sometimes that’s very difficult to do.

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The USGS does not examine the economics of power and energy sources. Williams says his office’s examination is purely technological.

The report does note, however, that there is new geothermal exploration being done all the time and states are building more geothermal power plants.

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On the Web:

USGS – Geothermal Research

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