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GEOEXCHANGE HEATING ,4N® COOLING SYSTEMS ,
<br />I n contrast to geothermal power genera-
<br />tion and direct use; geothermal heating
<br />and cooling systems, (also known as
<br />ground source heat pumps orgeoez-
<br />changesystems) can be installed in any
<br />community. They rely on the constant
<br />temperature ofthe earth below io feet
<br />in depth. Water (with antifreeze in cold
<br />climates) is passed through coils oftub-
<br />ingunderground, bringing it from air
<br />-temperature to approximately 5o degrees.
<br />The water preheats or cools air or water in
<br />the building heatingsystem.
<br />dress geothermal in an energy element or
<br />stand-alone geothermal element. Inclusion
<br />in a natural resources element is also com-
<br />mon. However, Churchill County, Nevada,
<br />includes development of industrial geother-
<br />mal inthe Economic Developmentsection of
<br />the Master Plan. In communities where hot
<br />springs are a significant aspect ofthe local
<br />economy, such as in Calistoga, Califomia,
<br />genera! plan policies often seekto balance
<br />utilization of deep geothermal resources for
<br />direct use orenergygeneration with ensur-
<br />ingthe ongoi ngquality of near-surface hot
<br />water resources.
<br />The extent and detail ofcomprehen-~
<br />sive planning around geothermal varies
<br />widely, even among communities with sig-
<br />nificant resources. The geothermal element
<br />for Imperial County, Califomia, is more
<br />than 8o pages long and provides extensive
<br />geothermal data as well as discussion of
<br />transmission limitations and expansion
<br />potential. Most communities' geothermal
<br />policies are much more modest-perhaps
<br />a few pages to a few paragraphs. One ex-
<br />cellent example of thorough, yet succinct,
<br />treatment in a comprehensive plan is the
<br />geothermal element ofthe Lake County,
<br />Califomia, zoo? general plan. In addition to
<br />definitions, it contains five major sections
<br />that address research and development,
<br />environmental protection, resource utili-
<br />zation, collaboration with other agencies
<br />and public outreach, and implementation
<br />-measures. ~ -
<br />For many communities, the best geo-
<br />thermal resources otturon federal lands
<br />where Local government has limited jurisdic-
<br />tion. Adoption ofdetailed zoning regulations
<br />may be unwarrpnted in these communities,
<br />as local review-if it occurs-is advisory
<br />According to the U.S. Department of
<br />Energy, geoezchange systems are z5 to 50
<br />percent more efficient i n their use ofelectric-
<br />itythan trod itidnal heating and cooling sys-
<br />tems.They are more expensive to install, but
<br />energy savings typically pay back the initial
<br />expense~within five to io years. The indoor
<br />equipment has a z5-year lifespan, while the
<br />underground coils can be expected to last
<br />5o years or more.
<br />Tens of thousands of geothermal heat
<br />pump systems have been installed in homes,
<br />institutions, and businesses in the United
<br />only.Inthese areas, comprehensive plan
<br />policies may be the best way to establish
<br />local preferences for geothermal develop-
<br />ment, including policies that seek local
<br />consultation during permitting. For example,
<br />the Mammoth Lakes, California, general
<br />plan includes a policythat seeks to annex
<br />any national forest lands on which future
<br />geoihermaldevelopmentoccurs.
<br />Mapping
<br />One difference among communities with
<br />geothermal potential that affects the types
<br />oftools and degree of protection the cdm-
<br />munityapplies tothe geothermal resource
<br />is the degree of detail known about the
<br />location ofthe geothermal resources.
<br />Known geothermal resource areas (KGRAs)
<br />are mapped in some communities, but
<br />many geothermal resources remain un-
<br />mapped. Furthermore, pinpointingthe
<br />precise location(s) to most effectivelytap
<br />into a known geothermal-resource can
<br />be expensive andtime-consuming. In a
<br />limited numberofcommunities, afederal
<br />research agency or other entity may have
<br />determined the location ofthe best drill-
<br />ingsites. Without such information, local
<br />planners may know onlythat geothermal
<br />development may be pbssible within a
<br />large, generalized area. Asageneral rule,
<br />the larger and Less certain the extent and
<br />location ofthe geothermal resource, the
<br />Less likely it is thatthe communitywill. be
<br />willing adopt protective regulations for
<br />the geothermal resource. It is difficultto
<br />justify regulations that would preclude
<br />potentially incompatible uses when the
<br />level of uncertainty about the potential and
<br />location of future geothermal development
<br />is high.
<br />States. Geoexchange systems are subject
<br />to the building code, which ensures that
<br />the coils are encased to prevent collapse
<br />or leakage. But in somecircumstances,
<br />there may be reason tb regulate geoex-
<br />change systems using zoning tools, as
<br />well. For.example, some communities
<br />specitysetbacksforundergroundcoils
<br />from property lines, rights-of--way, and
<br />surface waters. In other communities
<br />where artesian aquifers are present, it may
<br />be importantto establish the maximum
<br />allowed depth ofthe underground coils.
<br />Zoning Regulations
<br />Allowed/Conditional Use. Mostjuris-
<br />dictionswith KGRAs and some communi-
<br />tieSwith unmapped geothermal potential
<br />specify geothermal uses in lists ofallowed
<br />uses by zoning district. In most comm uni-
<br />ties, geothermal development is allowed as
<br />a conditional or special use. A few communi-
<br />ties, includingthe Town ofVale and Malheur
<br />County in Oregon, allow geothermal direct
<br />uses by right in heavy industrial zones.
<br />Where geothermal resources are adequate
<br />for energy production, most communities
<br />group all geothermal development as one
<br />use type, allowing direct and energy uses in
<br />the same pattern ofzoning district. However
<br />some, such as Malheur County and Sonoma
<br />County, California, distinguishbetween the
<br />two, allowing direct uses in some zoning
<br />districts and energy production in others.
<br />Other communities distinguish between
<br />wellfields and surface uses. For example,
<br />the zoning regulations in the Town ofMam-
<br />moth Lakes allow exploratory drillingfor
<br />geothermal in all zoning districts by right,
<br />while "geothermal production" maybe con-
<br />ditionally allbwed intwo zoning districts.
<br />Production drillingforwellfieldordirectuse
<br />is not regulated by zoning, but rather is sub-
<br />ject todiscretionary permits from the public
<br />works department.
<br />Definitions: It is important that zoning
<br />regulations define geothermal uses so that
<br />they can be regulated with similar uses. For
<br />example, many codes include geothermal
<br />power plants within the general definition
<br />of a power plant. Others include geother-
<br />mal exploration and drilling alongside
<br />otherexploratorydrtlling activities. Given
<br />the ownership structure for geothermal
<br />plants-which are typically owned by pri-
<br />ZONINGPRACTICE 5•io
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