All geothermal resources of the State of Colorado are administered by the State Engineer. The State Engineer has promulgated Rules and Regulations for Permitting the Development and Appropriation of Geothermal Resources Through the Use of Wells (“Geothermal Rules”) to enable the State Engineer to carry out the provisions of the Colorado Geothermal Resources Act, Sections 37-90.5-101 et seq, C.R.S. The Geothermal Rules establish minimum standards required for protecting the public health, safety, welfare, and the environment, and preventing the waste of geothermal resources that may result from the construction and use of geothermal wells. The current Rules became effective on September 30, 2004.
A “geothermal well” is defined as a well that is constructed for the purpose of exploration, use of a geothermal resource, or reinjection of a geothermal fluid. The term “geothermal well” includes loop fields in geoexchange systems, but does not include wells subject to the provisions of Articles 90 and 92 of Title 37, C.R.S. (conventional water wells). The Geothermal Rules define the following types of geothermal wells:
- “Geoexchange systems” (see below for a discussion of these systems);
- “Type A” – a well with a total depth not exceeding 2,500 feet or encountering geothermal fluids having a temperature not exceeding 212⁰F;
- “Type B” – a well with a total depth exceeding 2,500 feet or encountering geothermal fluids having a temperature exceeding 212⁰F;
- “Reinjection” (Type A or B) – a well to be used to reintroduce geothermal fluids back into the same reservoir from which they were produced, either by pressure at the surface or gravity flow.
Use Form GWS-45, General Purpose Water Well Permit Application to apply for a well permit, except for Geoexchange Systems, which require the use of Form GWS-72. Refer to the 2-page guide titled, Steps for Applying for Type A or B Geothermal Well Permit and to the Geothermal Rules for more information.
A geoexchange system is defined as a heat pump or heat exchange system having a horizontal or vertical closed-loop portion consisting of pipe buried in trenches, boreholes, or wells (ground-source), or submerged in a body of water (water-source), in which a heat exchange medium (fluid or vapor) is circulated and fully contained within the pipe or tubing. The purpose of the closed loop is to provide for the transfer of heat between the circulating fluid or vapor and the ground or water. Although these systems do not appropriate subsurface fluids, they do utilize the earth’s geothermal properties, therefore, requiring a permit. Prior to issuance of a permit, the applicant must become certified. Use Form GX-02 in applying for certification and Form GWS-72 for a permit to construct geoexchange system loop fields.