這項名為「地熱環境影響總結綱要報告」(Final Geothermal Programmatic Environmental Impact Statement) 的開發計畫，將劃定出由土地管理局管理約1億1800萬公頃的公有地、以及美國國家森林處管轄的7900萬公頃土地，作為未來開發地熱租賃。
然而地熱能仍尚存隱憂。乾式地熱發電（Dry steam power plants）與突發式地熱發電（flash steam power plants）仍會噴發出少量二氧化碳、一氧化氮和硫，雖然只有化石燃料發電的5%。
More than 190 million acres of federal land in 12 western states will be opened for development of geothermal energy resources, Secretary of the Interior Dirk Kempthorne announced today.
"Geothermal energy will play a key role in powering America's energy future,"Kempthorne said, "and 90 percent of our nation's geothermal resources are found on federal lands."
The plan would identify about 118 million acres of public lands managed by the Bureau of Land Management and 79 million acres of National Forest Service lands for future geothermal leasing.
"Facilitating their leasing and development under environmentally sound regulations is crucial to supplying the secure, clean energy American homes and businesses need," the secretary said in Phoenix where he has been attending the annual convention of the National Congress of American Indians.
There are 29 geothermal power plants currently operating on Bureau of Land Management lands in California, Nevada and Utah, with a total generating capacity of 1,250 megawatts, enough to supply the electricity needs of 1.2 million homes.
The largest group of geothermal power plants in the world is located in The Geysers, a geothermal field in California. Currently, geothermal power supplies less than one percent of the world's energy.
Under the plan announced today, known as the Final Geothermal Programmatic Environmental Impact Statement, 5,540 megawatts of new electric generation capacity from geothermal resources could be in place by 2015.
One megawatt of geothermal energy powers more than 1,000 homes, so if the newly announced plan is implemented, new geothermal energy could meet the needs of 5.5 million homes.
In addition, the plan estimates an additional 6,600 megawatts by 2025 for a total of 12,100 megawatts - enough to power more than 12 million homes.
Kempthorne points to growing interest in developing these resources shown by the results of recent Bureau of Land Management geothermal lease sales in areas where current Resource Management Plans already allow geothermal development.
An August 2007 sale drew the highest ever per-acre bid for a lease in The Geysers field. And a sale of leases in Nevada brought a record-breaking $28.2 million in August 2008.
Kempthorne noted the strong interest states, local communities, industry and environmental groups took in the development of this plan.
"This process has benefited greatly from the involvement of both governmental and nongovernmental stakeholders, and from the clear direction Congress gave in the 2005 Energy Policy Act," the secretary said.
There are environmental concerns around geothermal energy. Dry steam and flash steam power plants emit low levels of carbon dioxide, nitric oxide, and sulphur, although at roughly five percent of the levels emitted by fossil fuel power plants.
Hot water from geothermal sources will contain trace amounts of toxics such as mercury and arsenic, which if discharged into rivers can make the water unsafe to drink.
To protect special resource values, the plan announced today identifies a comprehensive list of stipulations, conditions of approval and best management practices required for approval of future geothermal leases.
The Bureau of Land Management and the U.S. Forest Service will publish the final version of the plan in the Federal Register on Friday, October 24, 2008.
It will be available online at http://www.blm.gov/Geothermal_EIS.