Article published Aug 13, 2007
Energy answers sought in Earth's crust
August 13, 2007

By Eliane Engeler and Alexander G. Higgins - BASEL, Switzerland (AP)

When tremors started cracking walls and bathroom tiles in this Swiss
city on the Rhine, engineers knew they had a problem.

"The glass vases on the shelf rattled, and there was a loud bang,"
recalled Catherine Wueest, a tea-shop owner. "I thought a truck had
crashed into the building."

But the magnitude 3.4 tremor on the evening of Dec. 8 was no ordinary
act of nature: It had been accidentally triggered by engineers
drilling deep into the Earth's crust to tap its inner heat and thus
break new ground — literally — in the world's search for new sources
of energy.

Basel was wrecked by an earthquake in 1365, and no tremor, man-made or
other, is to be taken lightly. After more, slightly smaller tremors
followed, Basel authorities told Geopower Basel to put its project on
hold.

But the power company hasn't given up. It's in a race with a firm in
Australia to be the first to generate power commercially by boiling
water on the rocks 3 miles underground.

On paper, the Basel project looks fairly straightforward: Drill down,
shoot cold water into the shaft and bring it up again superheated and
capable of generating enough power through a steam turbine to meet the
electricity needs of 10,000 households, and heat 2,700 homes.

Scientists say this geothermal energy — clean, quiet and virtually
inexhaustible — could fill the world's annual needs 250,000 times over
with nearly zero impact on the climate or environment.

A study released this year by the Massachusetts Institute of
Technology said that if 40 percent of the heat under the United States
could be tapped, it would meet demand 56,000 times over. It said an
investment of $800 million to $1 billion could produce more than 100
gigawatts of electricity by 2050, equaling the combined output of all
104 nuclear power plants in the U.S.

"The resource base for geothermal is enormous," Jefferson Tester, the
study's lead author, told the Associated Press.

But there are drawbacks — not just earthquakes but also cost. A
so-called hot-rock well 3 miles deep in the United States would cost
$7 million to $8 million, according to the MIT study. The average cost
of drilling an oil well in the U.S. in 2004 was $1.44 million,
according to the U.S. Energy Information Administration.

Also, rocks tapped by drilling would lose their heat after a few
decades, and new wells would have to be drilled elsewhere.

Bryan Mignone, an energy and climate-change specialist with the
Brookings Institution in Washington, said alternative sources of
energy face stiff price competition.

"Currently in the U.S., new technologies in the power sector are
competing against coal, which is very cheap," he said.

Humans have used heat from the earth for thousands of years. The
ancient Romans drew on hot springs for bathing and heating their
homes. Geothermal energy is in use in 24 countries, including the U.S.

But those sources — geysers and hot springs — are close to the
surface. Hot dry rock technology, also called "enhanced geothermal
systems" or EGS, drills down to where the layers of granite are close
to 400 degrees Fahrenheit. The equipment is similar to that used for
oil but needs to go much deeper and be wider to accommodate the water
cycle.

Hot dry rock technology is meant to stay well away from the 99 percent
of the Earth's interior that has temperatures of more than 1,000
degrees.

Aeneas Wanner, a Swiss expert, says that if you imagine Earth as an
egg, "a bore hole would only scratch the shell of the egg a little
bit."

The United States led the way in demonstrating the concept with the
Los Alamos geothermal project at Fenton Hill, N.M. The project begun
in the 1970s demonstrated that drilling 15,000 feet deep was possible
and that energy could then be extracted.

But the project came to a halt in 2000 when it ran out of funds.
Meanwhile, the MIT report said, problems encountered in testing have
been solved or can be managed — such as controlling how the water
flows underground or limiting earthquakes and chemical interactions
between water and rock.

Backers in the United States hope that government funding will
increase as oil and gas prices rise. But Steve Chalk, deputy assistant
secretary for renewable energy, said the Department of Energy won't
spend more money beyond the $2 million it has already allocated to
hot-rock technology.

However, he said the MIT study, which was funded by the Department of
Energy, serves as a basis for studying the idea further.

Major energy companies, including Chevron Corp., Exxon Mobil Corp. and
American Electric Power, told the AP they are following the research
but not investing in it.

"This is an interesting technology for Chevron, and we are currently
evaluating its potential," said spokesman Alexander Yelland.

In Basel, the first shaft was bored last year by a 190-foot-tall
drilling rig towering above nearby apartment buildings. Water was
pumped down the injection well in the test phase in December, and as
expected, it heated to above 390 degrees Fahrenheit as it seeped
through the layers of rock below.

But that's where the water remains for the time being; it caused the
rock layers to slip, causing the tremors and rumbles that spooked the
townspeople.

Geopower Basel had forecast some rock slippage. In fact, it said the
location on top of a fault line — the upper Rhine trench — was an
advantage because it meant the heat was closer to the Earth's surface.

But with $51 million already spent, drilling stopped and the official
launch date was moved back from 2009 to 2012.

Still to be drilled are the two wells that would suck the pressurized,
superheated water out of the cracks and up to the surface to create
steam for driving a turbine and generating electricity. The water,
having cooled to about 340 degrees Fahrenheit, would heat hospitals,
public buildings and homes before being pumped back into the ground
for another waste-free, gas-free cycle.

The rival project near the southern Australian town of Innamincka
faces more benign geological conditions and a smaller population. Its
target date for operations is now two years ahead of Basel's, aiming
to produce 40 megawatts of electricity by the end of 2010, enough to
supply more than 30,000 households.

Experts say hot-rock geothermal energy can operate 24 hours a day and
doesn't depend on sun or wind. But it's decades away from serious
rivalry with existing energy sources.

Susan Petty, one of the 18 co-authors of the MIT study, works for
Black Mountain Technology, a company promoting hot-rock energy. She
predicts that 10 percent of the world's power could come from
geothermal sources in the next 50 years from the current 0.3 percent
and rising to 50 percent in about 100 years.

Promoters of the technology say that although geothermal drilling is
costly, it's cheaper to run once it's in place. The MIT study said it
could provide electricity at competitive prices. Price comparisons
indicate that it could be cheaper than other forms of renewable
energy, including biomass and solar power.

"The outlook is very good that we can do it," said Karl Gawell,
executive director of the Washington-based Geothermal Energy
Association.

But others are waiting for proof that it's worth the expenditure.

"This technology sounds very promising," said Nick Nuttall, chief
spokesman of the U.N. Environment Program, "but let's wait and see."