Environmental Impact of Hydropower : An Overview of Environmental Measures and Their Impact on the Power System

Sammanfattning

The European Union implemented the Water Framework Directive in the year 2000 to protect and improve the freshwater resources within the union. This should, for example, be done by improving aquatic ecosystems. Swedish river systems contains large amount of hydropower, which affects the ecosystems in and around watercourses. To make sure the Water Framework Directive is followed, Sweden’s hydropower will go through modern environmental assessments. When implementing environmental measures within hydropower trade-offs between hydropower’s role in the power system and the needs of the local environment occur. Hydropower contributes with renewable energy and the ability to decide when hydropower should produce electricity, which helps balance generation and demand in the power system. The aquatic ecosystems in watercourses are complex ecological systems that hold a very high biodiversity. This project aimed to increase the interdisciplinary understanding, to ease the work with these challenging trade-offs. This has been done by providing a knowledge base of hydropower’s environmental impact to power engineers, as well as providing an example of how this knowledge can be used when analyzing the power system impact of implementing environmental measures. In this project, a literature study, interview study and case study have been conducted to fulfill this aim. The literature study and interview study provided knowledge of the environmental impact of hydropower and possible environmental measures. The case study analyzed the power system impact of implementing some chosen environmental measures. The literature study and interview study resulted in an extensive compilation of the environmental impact of hydropower. It includes hydropower’s impact on the connectivity in rivers, the decrease of runs and rapids, and changes from the natural flow regime. The interview study also contributed to an overview of possible environmental measures and a discussion of two important aspects to consider when prioritizing environmental measures, the fact that environmental measures are location specific and that high environmental benefits for low power system impact make environmental measures easier to implement. The result from the case study showed that the environmental measures considered impacted both the electricity production and the ability to decide when to produce electricity. The case study also showed that the size of the impact depended on factors like for example the level of water used for a measure. It is therefore important to find a balance between the two interests when deciding the levels for measures. This project concludes that when regarding environmental measures within hydropower interdisciplinary knowledge is important. A holistic understanding makes it possible for solutions to regard all aspects and ease the work with these types of challenging trade-offs.