Geothermal energy resources: potential environmental impact and land reclamation

With increasing costs, finite sources, and adverse environmental impacts of fossil fuels, global attention has focused on developing renewable and clean sources of energy. Although geothermal energy is considered one of the most promising sources of renewable and clean energy, it may not be as benign as widely believed. In this paper, we evaluate the environmental challenges for geothermal resource extraction and describe potential reclamation strategies for disturbed ecosystems. Generally, the environmental impacts of geothermal power generation and direct use are minor and in most cases controllable. Geothermal plants have low emissions of carbon dioxide, hydrogen sulfide, and ammonia, and low land and water usage; these impacts can be minimized through appropriate mitigation measures. Other potential emissions such as mercury, boron, and arsenic may result in local and regional environmental consequences, although their impacts are poorly understood on a global scale. Geothermal plants can alter vegetation and wildlife habitat by reducing species diversity and community composition. There are small risks of subsidence, induced seismicity, and landslides, with potential serious consequences. Integration of timely reclamation during and after plant operation can significantly contribute to reducing long term reclamation costs while enhancing ecosystem recovery. This paper is expected to contribute to understanding environmental impacts associated with geothermal energy production and to determining appropriate mitigation and land reclamation strategies.