소수력발전소 개발사업의 환경적 고찰

Abstract

The energy produced by a small hydropower(SHP) plant is considered as a clean energy product because it is recycled from natural resource. In Korea, Forty-four SHP power plants have been built and operated since 1982 until now. However, lately, environmental and social problems have been presented during construction of SHP power plants. It is time we consider these issues, relating them to the targets of the government policy on energy production by SHP. In this study, we examined problems and undesirable effects on the overall river ecosystem that result from the construction and operation of SHP plants. We also suggested potential alternations. In order to understand the problems, we investigated and compared the ecosystem of the Nakdong river near 3 SHP plants and one plant construction site planned there. We observed the change and impact that the plants gave to the river ecosystem. All three operating SHP plants caused negative impacts to both upper and lower river ecosystem in terms of ecological, physical, and scenic aspects. The physical and ecological status, and water quality of the river had been seriously altered. Also the dryness and degradation of the river causes destruction in structure and function of the river ecosystem, therefore, obviously affecting the residential quality. On the contrary, the river near the plant construction site maintained naturalness and intact ecological conditions. This was proved by the existence of various numbers of benthic species which inhabit only in a clean river ecosystem. The inhabitation of the river otter(Lutra lutra), an endangered species protected by the law and top predator, that prefers such an environment, proves this fact also. Therefore, such problems can not be solved by the energy producing plan of the SHP and the siting plan that is used to construct the SHP plant. Until 2012, the target of SHP energy production that the government plans can be achieved by constructing 181 sites of 3,000kW SHP plants in the class of a national river, such as the Hongchun river. If the SHP plants are constructed in four national rivers and the Hongchun river, 36 plants per river will be constructed. This is certainly an unsuitable plan which should be replaced by various alternatives. In fact, dams for the SHP should not be sited in the mainstream of the national river any more because it causes serious impacts in the river ecosystem and in the resident life surrounding the site. Economically the government supports 70% of the construction cost and buys electricity, generated from the SHP, with almost same price of the electricity selling unit price on the base of 2004. This allows the private company to use the national river that is common property of all people and to gain an expensive profit privately, instead causing to destroy important river ecosystem. Because this imposes the cost to both the public and the nation, it is hard to consider as an effective use of a national budget. Accordingly it is possible to evaluate that the SHP does not create a public benefit, but result loss of a national budget. Thus, it is pertinent to recover economic values of natural ecosystem with which all the public can share, compared with the benefit that a private company can earn from the SHP in the national river. This suggests that various alternatives to replace the development of the SHP plant should be considered in the planning of the future energy policy, such as various ideas to produce energy from other natural resources, use of nuclear energy in the range that is not burdened additionally at the present level of nuclear waste treatment, and utilization of a pumping water hydropower which causes far less environmental impacts. If a dam site for the SHP is inevitable in the national river, a tributary which has a proper size of catchment may be considered to utilize. In this case the production of the amount of electricity will increase if the difference of elevation between an electric facility and a reservoir increases. Other alternatives of the SHP would be to utilize a sewage plant, a clean water plant, and various reservoirs which were already present.