Agenda - Planning Commission - 06/03/2010

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on the number of wells and rate ofdevelop- ment. Effects on both human and wildlife populations in the vicinity can be negative duringthis period. Anecdotal evidence from installed plants suggeststhatwithin a few years after drilling is completed, all or most species ofwildlife return. Steam emissions from an pperating geothermal plant or direct use creates constant, hissing"white noise" at a level comparable to other industrial uses. Drilling for direct uses is similar, but because these uses often require only one well, the duration of drilling is much shorter. Most geothermal surface uses (i.e., both power plants and direct uses) are readily able to comply, through a combination of development may raise concerns about pos- sibleimpacts onthese features. Most often, surface features do not coincide with the best areas to ddll wells, and utilization of deep re- sourceswill not affect surface features. How- ever, it is often difficult to say with absolute certainty ifand haw geothermal resources maybe linked belowthe ground, orto rule out all possibility of changes to surface re- sources.When use ofthe surface resources underpins the local economy, suchas in Pagosa Springs, Colorado, the community is typicallyverycautious about embracing geo- thermaldevelopment. In some cases, geothermal energy development may require additional tmns- Local communities with geothermal resources often recognize that the resource has the potential to offer clean energy and economic development benefits that align with community goals.. technology or land acquisition, with typi- calnoise standards of65 to 6o decibels as measured atthe property line. Other Attributes and Land-Use Impactr Several other typical attributes of geother- maldevelopmentwarrantbriefinention. The transfer of hot vapor and Fluid from a geothermal wellfield to the end use in- volves miles of pipes thatcan be quite hot. Although insulated, the pipes could pose a hazard to anyone that would tam per with them. Also, warmth from the pipes can cre- ate microclimates that are atypical ofthe surrounding area. The im pact of this warmth on wildlife may be positive or negative. Some species congregate nearwarm geo- thermal infrastructure duringwinter months. A concern often voiced by local resi- dents isthat geothermal resource develop- mentand use wilt increase seismic activity. Whife the fear that geothermal exploration maytriggeran earthquake is unfounded, it is possible that seismic activity may be induced by drilli ng or removal of geothermal fluids. According to the U.S. Department of Energy, such activity is of such small magnitude pess than z.5 on the Richterscale) and duration that it cannot be felt at the surface. However, some residents neargeothernialdevelop- mentreport noticing increased seismicity. In communities with surface geothermal features such as hot springs, geothermal mission lines. Although land-use impacts oft~ansmissipn are not addressed in this article because they are not unique to geo- thermaldevelopment, transmission lines may be an important consideration in local geothermal permitting decisions. Fnally, land subsidence-where an area of land sinks-is another possible impact of geothermal development due to the removal of Fluid and gas from the underground geothermal reservoir:;Subsid- ehcethat isdetectable onthe surface is rarely a result of geothermal development, is genemllyvery limited, and can be minimized by reinjectingfluid back into the reservoir. PLANNING TOOLS FOR GEOTHERMAL DEVELOPMENT The permitting process for geothermal power plants and direct uses is multilay- ered and time-consuming. Geothermal well drilling and production emissions are sub- ject to state and federal regulations forwell drilling, air quality, and water quality. Many geothermal resources are located on public lands~controlted by agencies with their own study and reporting requirements. And, like other power plants, the use is subjectto some regulations in the Homeland Security Act, such as being fully enclosed within fencingthat is secure and allows forvis- ibility ofany approaching potential threat. Local regulations and permitting processes are in addition to these other permitting requirements. Local communities with geothermal resources often recognize that the resource has the potential to off, er clean energy and economic development benefits that align with community goals. Thus, they seek to use planningtools to encourage safe de- velopment ofgeothermal resources, and to maintain the resource far potential future development. The remainder of th is article describes some ofthe common tools and approaches that local governments are us- ing toaddress geothermal development. Comprehensive Plans Some communities with identified geother- malresources are using comprehensive planni ng to set policy for potential geother- mal development. Comprehensive plans can . help indicate the desire ofthe community with regard to geothermal resource develop- mentand lay the groundwork for codified regulations. Most comprehensive plans ad- ZONINGPRACCfICE. 5•io 86 AMERIGW PIANNING p5s0[IAnON~pageq