Junona Jonas, Alameda Power & Telecom
Alameda Power & Telecom has firsthand experience with geothermal energy. For the past 20 years, our municipal utility, a department of the City of Alameda, Calif., has used this clean, renewable resource to generate electric power for our customers.
Today, more than 80 percent of our electric power is generated using renewable energy sources—more than 50 percent of which is geothermal. As one of the 14 members of the Northern California Power Agency (NCPA), Alameda Power & Telecom is part owner of the geothermal power plants from which we derive this renewable energy.
The NCPA geothermal facility (see photo), which started generating electricity in 1982, uses steam from The Geysers in Northern California, which is the world’s largest geothermal field.
In this month’s edition of power pointers, Alameda discusses the basics of geo-thermal power production.
What is geothermal energy?
Geothermal energy is heat (thermal) derived from the earth (geo). It is the thermal energy contained in the rock and fluid that fills the fractures and pores within the rock in the earth’s crust.
How is electric power generated using geothermal energy?
Power plants generate electricity from geothermal reservoirs. Deep wells—more than a mile deep—are drilled into underground reservoirs to tap steam (from 250 to 700 F) to drive turbines that, in turn, drive electricity generators.
What are the benefits of using geothermal energy?
First, geothermal energy is clean. Energy can be extracted without burning a fossil fuel such as coal, gas or oil. Geothermal fields produce only about one-sixth of the carbon dioxide created by a natural-gas-fueled power plant.
Additionally, geothermal energy is readily available. Geothermal power plants have average availabilities of 95 percent or higher, compared to 60 percent to 70 percent for coal and nuclear plants.
Finally, geothermal power is renewable, as its source is heat generated by the Earth’s core. Even in geothermal areas dependent on a reservoir of hot water, water can be reinjected, making it a sustainable energy source. For example, wastewater from the nearby community of Clear Lake is used at The Geysers power plants as reinjection fluid. This prolongs the life of the reservoir as it reuses the wastewater.
Where are geothermal power generations typically located?
Hydrothermal resources—reservoirs of steam or hot water—are available only in the western United States, Alaska and Hawaii. Other enormous and worldwide geothermal resources—hot dry rock and magma, for example—are awaiting further technology development.
Do geothermal power plants have special space or equipment requirements?
Geothermal power plants use relatively small areas and don’t require storage, transportation or combustion of fuels. The U.S. Department of Energy states that the average geothermal power plant requires a total of only 400 square meters of land, or approximately one-tenth of an acre, to produce a GW of power over 30 years.
How much electricity can be generated from geothermal power plants in the U.S.?
According to the Geothermal Education Office, almost 3,000 MW of geothermal generation capacity is available from power plants in the western United States, the equivalent to burning 60 million barrels of oil each year.
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Some two percent of Utah’s electricity, four percent of California’s electricity and ten percent of northern Nevada’s electricity is generated using geothermal energy.
How much does geothermal energy cost per kWh?
According to the U.S. Department of Energy, electricity produced by geothermal power plants is becoming cost-competitive with other forms of energy. The cost of geothermal electricity currently ranges from about 4 to 8 cents per kWh. The DOE is working with the geothermal industry to bring the cost down to 3 cents per kWh.
Where does geothermal energy rank among other renewable energy sources?
The current production of geothermal energy from all uses places third among renewable sources, following hydroelectricity and biomass but ahead of solar and wind. According to industry sources, the current level of geothermal use pales in comparison to its potential.
Where can I find more information on geothermal energy?
Try the following Web sites: Geothermal Education Office (www.geothermal.marin. org), Geothermal Resources Council (www.geothermal.org), U.S. Department of Energy (www.eren.doe.gov/geothermal), or pick up the NCPA geothermal power facility brochure.
Jonas is the manager of Alameda Power & Telecom in Alameda, California. Under her leadership, the municipal utility has earned national recognition for its clean energy generation initiatives. She can be contacted at [email protected] or 510-748-3901.
Founded in 1887, Alameda Power & Telecom is the municipal utility serving approximately 33,000 customers in Alameda. For more information, please visit www.alamedapt.com.
