New research from SMU's Geothermal Laboratory, funded by a grant from Google.org, documents significant geothermal resources across the United States capable of producing more than three million megawatts of green power – 10 times the installed capacity of coal power plants today.
mapping produced from the research, viewable via Google Earth at www.google.org/egs/,
demonstrates that vast reserves of this green, renewable source of power
generated from the Earth's heat are realistically accessible using current
of the new research, from SMU Hamilton Professor of Geophysics David Blackwell
and Geothermal Lab Coordinator Maria Richards, confirm and refine locations for
resources capable of supporting large-scale commercial geothermal energy
production under a wide range of geologic conditions, including significant
areas in the eastern two-thirds of the United States. The estimated
amounts and locations of heat stored in the Earth's crust included in this
study are based on nearly 35,000 data sites – approximately twice the number
used for Blackwell and Richards' 2004 Geothermal Map of North America, leading
to improved detail and contouring at a regional level.
the additional data, primarily drawn from oil and gas drilling, larger local
variations can be seen in temperatures at depth, highlighting more detail for
potential power sites than was previously evident in the eastern portion of the
For example, eastern West Virginia
has been identified as part of a larger Appalachian trend of higher heat flow
geothermal production has been restricted largely to the western third of the
country in geographically unique and tectonically active locations. For
instance, The Geysers Field north of San
Francisco is home to more than a dozen large power
plants that have been tapping naturally occurring steam reservoirs to produce
electricity for more than 40 years.
newer technologies and drilling methods now can be used to develop resources in
a wider range of geologic conditions, allowing reliable production of clean
energy at temperatures as low as 212 degrees F and in regions not previously
considered suitable for geothermal energy production. Preliminary data released
from the SMU study in October 2010 revealed the existence of a geothermal
resource under the state of West
Virginia equivalent to the state's existing (primarily
coal-based) power supply.
again, SMU continues its pioneering work in demonstrating the tremendous
potential of geothermal resources," says Karl Gawell, executive director
of the Geothermal Energy Association. "Both Google and the SMU researchers
are fundamentally changing the way we look at how we can use the heat of the
Earth to meet our energy needs, and by doing so are making significant contributions
to enhancing our national security and environmental quality."
assessment of geothermal potential will only improve with time," says
Blackwell. "Our study assumes that we tap only a small fraction of the
available stored heat in the Earth's crust, and our capabilities to capture
that heat are expected to grow substantially as we improve upon the energy
conversion and exploitation factors through technological advances and improved
and Richards first produced the 2004 Geothermal Map of North America, using oil
and gas industry data from the central United States. Blackwell and the 2004
map played a significant role in a 2006 Future of Geothermal Energy study
sponsored by the U.S. Department of Energy that concluded geothermal energy had
the potential to supply a substantial portion of the future U.S.
electricity needs, likely at competitive prices and with minimal environmental
impact. SMU's 2004 map has been the national standard for evaluating heat flow,
temperature and thermal conductivity for potential geothermal energy projects.
newest SMU estimate of resource potential, researchers used additional
temperature data and in-depth geological analysis for the resulting heat flow
maps to create the updated temperature-at-depth maps from 11,500 feet to 31,000
feet. This update revealed that some conditions in the eastern two-thirds of
the United States
actually are hotter than some areas in the western portion of the country, an
area long-recognized for heat-producing tectonic activity. In determining the
potential for geothermal production, the new SMU study considers the practical
considerations of drilling, and limits the analysis to the heat available in
the top 21,500 feet of crust for predicting megawatts of available power. This
approach incorporates a newly proposed international standard for estimating
geothermal resource potential that considers added practical limitations of
development, such as the inaccessibility of large urban areas and national
parks. Known as the technical potential value, it assumes producers tap only 14
percent of the theoretical potential of
stored geothermal heat in the United
States, using currently available
recent technological developments already have sparked geothermal development
in areas with little or no tectonic activity or volcanism:
1. Low Temperature Hydrothermal – Energy is
produced from areas with naturally occurring high fluid volumes at temperatures
ranging from less than boiling to 300 degrees F. This application is currently
producing energy in Alaska, Oregon,
Idaho and Utah.
2. Geopressure and Coproduced Fluids Geothermal
– Oil and/or natural gas are produced together with electricity generated from
hot geothermal fluids drawn from the same well. Systems are installed or being
installed in Wyoming, North Dakota, Utah, Louisiana, Mississippi and Texas.
3. Enhanced Geothermal Systems (EGS) –
Areas with low fluid content, but high temperatures of more than 300 degrees F,
are "enhanced" with injection of fluid and other reservoir
engineering techniques. EGS resources typically are deeper than hydrothermal, and
represent the largest share of total geothermal resources capable of supporting
larger capacity power plants.
A key goal
in the SMU resource assessment was to aid in evaluating these nonconventional
geothermal resources on a regional to sub-regional basis.
particular geothermal interest include the Appalachian trend (western Pennsylvania, West Virginia,
to northern Louisiana), the aquifer heated
area of South Dakota, and the areas of
radioactive basement granites beneath sediments such as those found in northern
Illinois and northern Louisiana. The Gulf Coast
continues to be outlined as a huge resource area and a promising sedimentary
basin for development. The Raton Basin in southeastern Colorado
possesses extremely high temperatures, and is being evaluated by the State of Colorado, along with an
area energy company.
Geothermal Mapping Report Confirms Vast Clean Energy Source
October 28, 2011