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Environmental groups: Why Geothermal?

  1. What are the primary environmental issues related to geothermal development?
  2. For more information

1. What are the primary environmental issues related to geothermal development?
  • Air emissions
  • Land use
  • Water quality, brine, and solid wastes
  • Noise pollution

Information cited is from Geothermal Literature Assessment: Environmental Issues, a bibliographic review published in May 2004 by the Geothermal Energy Association.

Air emissions

Arsenic (As)
"It is generally known that arsenic is found in pipeline scale and within the liquid phase of geothermal fluids, as opposed to the steam or in the non-condensable gases. Thus, geothermal power plants are not to be considered high arsenic emitters."

Hydrogen Sulfide (H2S)
"...geothermal plants do not exceed state air quality and regulations regarding H2S due to abatement technology that has been developed and effectively employed."

Mercury (Hg)
The Environmental Protection Agency (EPA) did not recognize new mercury emissions data until 2003. "...mercury emissions continue to be an unnecessary point of contention and concern..."

Nitrogen oxides (NOx)
"Some geothermal plants emit only minor amounts of nitrogen oxides through the process of H2S incineration."

Particulate matter (PM10)
"...emissions are well below the federal limits. Only plants with cooling towers emit small amounts of particulate matter."

Land use

Induced seismicity
"Geothermal resources are almost always found in places that are very tectonically active, which means that these areas will be subject to a great deal of geological activity even in the absence of field development...The literature appears to indicate that geothermal operation can indeed cause some seismic activity, but the earthquakes that are generated are extremely small and weak..."

Land use conflicts
"Although geothermal power development generally requires less land than coal or nuclear technologies, its use is still sometimes seen as controversial, and raises several land-use issues...Although conflicts over agricultural uses can generally be resolved during the leasing process, conflicts over land for recreational or religious purposes are generally more difficult to overcome."

"Because geothermal operations take place in areas that are very tectonically active, it is often difficult to distinguish between geothermal-induced and naturally occurring events. However, geothermal energy production has been shown to at times results in land subsidence...Reijection has been shown to help reduce the effects of subsidence."

Water quality, brine, and solid wastes

Geothermal brines
"...modern drilling and casing technology have been effective in protecting groundwater and reinjection of spent brines has served to maintain reservoir pressures and avoid effects of discharge to surface waters.""Current brine research is focused on the extraction of metallic and non-metallic elements...[which] offsets mining..."

Geothermal sludge
"Geothermal power plants that utilize cooling towers accumulate sludge during normal operation. This sludge, commonly comprised or sulfur, has to be dealt with as a hazardous waste and properly disposed of. Current studies have focused on how to more efficiently and cost-effectively dispose of the sludge."

Reinjection technology
"The development of reinjection technology has greatly helped geothermal plants with the disposal of brine in a safe and effective way."

Water rights and competing uses
"...since reinjection...water rights and geothermal development's impacts on other water uses have not been a major problem...treated wastewater from local communities can be injected into geothermal reservoirs to help preserve the life of the field."

Noise pollution

"Geothermal development is a somewhat noisy process, and mitigating noise pollution should be taken into consideration, especially when developing geothermal resources near residential areas. However, how serious a problem noise pollution is for the industry is not clear from the published literature...most of the data cited...[is from] a report done by the Department of Interior in 1973."


2. For more information

Defenders of Wildlife, Geothermal Energy Resources, Principles and Recommendations.

Geothermal Energy Association, A Guide to Geothermal Energy and the Environment, Earth Day 2005.

Geothermal Resources Council, Geothermal Energy Abstract Sets, Special Report No. 14, 1984-1985.

U.S. Department of Energy - Energy Efficiency and Renewable Energy, Geothermal Technologies Program, Environmental Impacts of Using Geothermal Energy.


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Current Solicitations / Subscribe to Newsletter / Financing Information / Why Geothermal? is produced with support from the US Department of Energy, Assistant Secretary for Energy Efficiency and Renewable Energy, Geothermal Technologies Program. Neither the US Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the US Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the US Government or any agency thereof.

Updated 29-Nov-2005

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