Air Quality and Plant Eco-Physiological Responses Around Geothermal Power Plants in Iceland and Kenya

摘要

As with most energy development technologies, environmental effects must be anticipated. Geothermal energy has proven intrinsic reliability and environmental viability compared to other finite and infinite energy sources. Nonetheless; further studies to complement existing monitoring and mitigation measures is the cumulative impact of H_2S and trace element emissions to vegetation. Believed to be a source of S, H_2S may contribute significantly to plant nutrition or if in excess act as a phyto-toxin. Given the anticipated and progressive world geothermal development, an understanding of the emission cycle and potential effects to vegetation is pertinent toward planning and executing feasible mitigation measures toward sustainable development. Presented herein are research plans within the Nesjavellir and Hellisheidi geothermal power plants in Iceland and Olkaria geothermal power plant in Kenya. Two key questions guide the study; 1) plant species response to changing air quality and manifestations? 2) concentrations of potentially phyto-toxic geothermal elements in plant species around power plants and threshold levels? The moss Racomitrium lanuginosum (Iceland) and the shrub Tarchonanthus camphoratus (Kenya) will be evaluated for signatures of any potential damage and growth stimulatory effects at varying distances and transects from the power plants. Concentrations of H_2S - S, As, Hg, B and Sb will be traced in steam, air and related to the concentrations in plants and soil. All measured concentrations and effects will be correlated to controls for comparison and inferences. In an outdoor experiment, the two plant species shall be re-grown in trays and irrigated with different known levels of H_2S dissolved in distilled water to determine threshold levels and responses. Findings of this study are expected to significantly aid in determination of the cumulative impacts of geothermal emissions to native plant species, and input to considerations of the evaluation of H_2S and emission control strategies/ abatement systems. Further advising policy makers and reducing any anticipated development ambiguities or opposition. This will ultimately strengthen the impetus promoting geothermal energy as the 'green 'solution to world energy needs.