Geoscientists Cite 'Critical Need' for
Basic Research to Unleash Promising Energy Resources
Nov 30, 2012 - ScienceDaily
ScienceDaily (Nov. 30, 2012) — Developers of renewable
energy and shale gas must overcome fundamental geological
and environmental challenges if these promising energy
sources are to reach their full potential, according to
a trio of leading geoscientists.
Their findings will be presented on Dec. 4 at the fall
meeting of the American Geophysical Union (AGU) in San
Francisco."There is a critical need for scientists
to address basic questions that have hindered the development
of emerging energy resources, including geothermal, wind,
solar and natural gas, from underground shale formations," said
Mark Zoback, a professor of geophysics at Stanford University. "In
this talk we present, from a university perspective, a
few examples of fundamental research needs related to improved
energy and resource recovery."
Zoback, an authority on shale gas development and hydraulic
fracturing, served on the U.S. Secretary of Energy's Committee
on Shale Gas Development. His remarks will be presented
in collaboration with Jeff Tester, an expert on geothermal
energy from Cornell University, and Murray Hitzman, a leader
in the study of "energy critical elements" from
the Colorado School of Mines.
Enhanced geothermal systems
One option for transitioning away from our current hydrocarbon-based
energy system to non-carbon sources is geothermal energy
-- from both conventional hydrothermal resources and enhanced
geothermal systems," said Zoback, a senior fellow
at the Precourt Institute for Energy at Stanford.
Unlike conventional geothermal power, which typically depends
on heat from geysers and hot springs near the surface,
enhanced geothermal technology has been touted as a major
source of clean energy for much of the planet.
The idea is to pump water into a deep well at pressures
strong enough to fracture hot granite and other high-temperature
rock miles below the surface. These fractures enhance the
permeability of the rock, allowing the water to circulate
and become hot.
A second well delivers steam back to the surface. The steam
is used to drive a turbine that produces electricity with
virtually no greenhouse gas emissions. The steam eventually
cools and is re-injected underground and recycled to the
In 2006, Tester co-authored a major report on the subject,
estimating that 2 percent of the enhanced geothermal resource
available in the continental United States could deliver
roughly 2,600 times more energy than the country consumes
But enhanced geothermal systems have faced many roadblocks,
including small earthquakes that are triggered by hydraulic
fracturing. In 2005, an enhanced geothermal project in
Basel, Switzerland, was halted when frightened citizens
were shaken by a magnitude 3.4 earthquake. That event put
a damper on other projects around the world.
Last year, Stanford graduate student Mark McClure developed
a computer model to address the problem of induced seismicity.
Instead of injecting water all at once and letting the
pressure build underground, McClure proposed reducing the
injection rate over time so that the fracture would slip
more slowly, thus lowering the seismicity. This novel technique,
which received the 2011 best paper award from the journal
Geophysics, has to be tested in the field.
Zoback also will also discuss challenges facing the emerging
shale gas industry. "The shale gas revolution that
has been under way in North America for the past few years
has been of unprecedented scale and importance," he
said. "As these resources are beginning to be developed
globally, there is a critical need for fundamental research
on such questions as how shale properties affect the
success of hydraulic fracturing, and new methodologies
the environmental impact of shale gas development."
Approximately 30,000 shale gas wells have already been
drilled in North America, he added, yet fundamental challenges
have kept the industry from maximizing its full potential. "The
fact is that only 25 percent of the gas is produced, and
75 percent is left behind," he said. "We need
to do a better job of producing the gas and at the same
time protecting the environment."
Earlier this year, Zoback and McClure presented new evidence
that in shale gas reservoirs with extremely low permeability,
pervasive slow slip on pre-existing faults may be critical
during hydraulic fracturing if it is to be effective in
Even more progress is required in extracting petroleum,
Zoback added. "The recovery of oil is only around
5 percent, so we need to do more fundamental research on
how to get more hydrocarbons out of the ground," he
said. "By doing this better we'll actually drill
fewer wells and have less environmental impact. That
all of the companies and the entire nation."
Energy critical elements
Geology plays a surprising role in the development of renewable
It is not widely recognized that meeting domestic and worldwide
energy needs with renewables, such as wind and solar, will
be materials intensive," Zoback said. "However,
elements like platinum and lithium will be needed in
significant quantities, and a shortage of such 'energy
could significantly inhibit the adoption of these otherwise
Historically, energy critical elements have been controlled
by limited distribution channels, he said. A 2009 study
co-authored by Hitzman found that China produced 71 percent
of the world's supply of germanium, an element used in
many photovoltaic cells. Germanium is typically a byproduct
of zinc extraction, and China is the world's leading zinc
About 30 elements are considered energy critical, including
neodymium, a key component of the magnets used in wind
turbines and hybrid vehicles. In 2009, China also dominated
the neodymium market.
How these elements are used and where they're found are
important issues, because the entire industrial world needs
access to them," Zoback said. "Therefore, if
we are to sustainably develop renewable energy technologies,
it's imperative to better understand the geology, metallurgy
and mining engineering of these critical mineral deposits."
Unfortunately, he added, there is no consensus among federal
and state agencies, the global mining industry, the public
or the U.S. academic community regarding the importance
of economic geology in securing a sufficient supply of
energy critical elements.