COM 0421.084 2012-2014 - Laserfiche WebLink

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OCT-01-2013 09:38 FROM:PARADISE BUSINESSCTR 18089652122 TO:9618912 P.6'24 activists. Recent(2007-08)consultation and review by geothermal proponents has v-ri fled that the same basic technologies, impacts,issues and concerns remain accurate and pertinent to g-'thermal projects L. operating and/or being proposed today.Additionally,the original report has been up�ated to incorporate more recent geothermal issues,including issues associated with Oregon's Newberry]exploration project of 2008. With informed citizen involvement,and adherence to democratic process,co munit.ies allected by proposed and existing geothermal production can best assess the.prospects and cons•quences of geothermal energy development, arriving at informed decisions that uphold the pub ic's best long-term interests and protect the natural heritage of those here today,including Earth's man imperiled species,as well as those yet to he horn. Environmental Impacts& Methods of Commercial-Scale Geothermal Energy Production Geothermal power production extracts heated fluids or dry steam by means c'rf wells tapping into heated reservoirs and rocks within the earth. The heated fluid is used to drive turbi es,generating electricity.' They type and temperature of geothermal reservoirs varies,each often omcwhat unique to its own area." Temperatures of reservoirs utilized for electrical production range from 120°C'to above 260° C.'° Fluids from these reservoirs can he in the form of dry steam or hot brines or w ter. Geothermal fluids varying compositions of toxins and heavy metals,are the primary source of g•othennal energy production's environmental problems and challenges. Geothermal production meth ids and processes most oten involve atmospheric emissions,condensation drift from cooling towers, aStewater,sludge, and reinjection of geothermal effluent—all containing various amounts of dangerou toxins.'" Basic geothermal electrical generation processes consist of:dry steam,singl flash,double flash, and binary cycle power plants. The type of geothermal fluids and the degree of tcmPeraturc in part determine the typed of plant utilized." Dry steam:Geothermal reservoirs comprised of dry steam are geologically rare'It is this type however,where electrical power generation from geothermal fluids began; in 1904 t C.ardarcllo,Italy.' Within the U.S.geothermal energy production began in 1955 at the"Geysers"loeat'd in California_ At the time of this report, 1990, these were still the only dry steam reservoirs commere ally generating electricity with the U.S.v" Geysers area geothermal resources and energy produCtio have been the locus of significant research and ongoing study. In the dry steam method wells tap the st am sending it through a"rock catcher"and afterwards into a turbine. To increase efficiency a vacuum is rutted at the turbine's exhaust by means of condensers. Cooling towers arc used for the spent steam,with the collected condensation injected back into the reservoir.°"' Single.flash: Designed for geothermal reservoirs with water temperatures in c cess of 220°C,these utilize wells,directing water"production separators," The pressures within the sep ators are kept at a lower level causing .15 to 20%of the hot fluid to flash into steam. From here the st am travels through scrubbers to power the turbine. Cooling towers and condensers are utilized similar to dry steam. Condensate and fluid from the separator is collected and reinjected into the geothermal reservoir.' Double flash: Ibis method is similar to the single flash system but,as its ram implies, flashes the fluid into steam a second time at a lower pressure, maximizing the energy products n potential of the geothermal fluid. As with the single flash system the excess fluids are collected an reinjected.' Binary cycle:This method does not use the geothermal fluid directly to power he turbine(s)as do the others. Instead,it directs the fluid through a heat exchanger where a secondary flu d is flashed into steam, Called the"working fluid",the secondary fluid is usually isobutane or freon(or si ilarlderivative fluids) 5