본 연구는 지열에너지 개발 및 이용에 따른 환경적 영향을 분석하고, 사업계획, 설치, 운영 및 폐쇄 과정에서 나타나는 환경적 문제점 및 제도적 문제점들을 분석하여 개선방안을 모색함으로써 지열에너지의 환경친화적인 개발과 이용 확대를 위한 정책적 추진 방향을 제시하고자 수행되었다. 지열에너지는 저온의 열수를 난방·급탕 등에 직접 이용하거나 지하의 연중 일정하게 유지되는 온도를 냉난방 등에 활용하는 천부지열 이용과 고온열수를 이용하여 전력을 생산하는 심부지열 이용으로 나뉘는데, 각각에 따라 적용되는 기술·환경적 문제점 등이 상이하게 다르므로 이를 구분하여 연구를 수행하였다. 연구의 결과로서 천부지열 이용 부문에서는 환경관리지침 개선, 전문인력 참여방안, 이력관리도입, 지열공 시공비 현실화를 제시하였으며, 심부지열이용 부문에서는 관련 법규의 제정방향과 신재생에너지 의무할당제도의 적용 및 개발 리스크 지원제도 운영을 제시하였다.

Geothermal energy utilization includes direct uses of hot water, and indirect uses of shallow geothermal energy for air-conditioning (heating/cooling) and deep geothermal energy for electric power generation. This study is to present various policies for environment-friendly development and utilization of geothermal energy, and its dissemination. For this purpose, the available potential of geothermal energy (including both shallow and deep geothermal energy) is estimated, and compared with the spreading target value of the government. Estimated available potential of geothermal energy in Korea is 20,988ktoe/year, which is seventeen times as much as the government spread target value for 2030. Yet, economic feasibility and sustainability in utilization of geothermal energy should additionally be taken into account for effective and sustainable uses of geothermal energy resources. Geothermal energy utilizations can make environmental influences such as contaminants leakages in processes of well drilling or/and managements, groundwater quality and quantity changes, land subsidence, and so on for shallow geothermal energy utitlizations. For deep geothermal energy utilizations, some environmental impacts include aquifer contamination due to hazardous materials in hot groundwater, atmospheric pollution, microearthquakes, landscape changes, land subsidence, and so on. Among aforementioned environmental problems, some can be resolved with aid of technology developments, but regulatory supports should be improved for effective and eco-friendly developments and utilizations of geothermal energy, and its dissemination. This study proposes several policy suggestions to enhance geothermal energy utilizations in an effective, eco-friendly, sustainable manner. For environment-friendly development and effective dissemination of shallow geothermal energy utilization, three improved policies are suggested. First, geothermal environmental management guidance should be unified so that it can be applied to all geothermal air-conditoning facilities. Second, construction costs of geothermal air-conditioning systems should reasonably be set in consideration of real costs in well developments. Moreover, history management systems should be implemented for effective management. In history management systems information on geothermal energy facilities from installation to closure should be recorded and preserved. For deep geothermal energy, most fundamental obstacle to effective developments and utilizations is lack of legislative bases related to deep geothermal energy. Thus, geothermal law should be enacted for specifying definition, resource classification and ownership of deep geothermal energy. Second, renewable energy certificate weight should be applied to geothermal power generation as geothermal energy is used for power generation. Lastly, the financial supporting system should be established so that it can reduce of the investment risk in the early stages of the geothermal power plant developments.