Study On Cumulative Effects And Life Cycle Assessment Of Cascade Hydropower Plants

Hydropower is clean and renewable energy. On the one hand, hydropower can bring enormous economic, social benefits, and environmental benefits, because hydroelectricity can save a large number of fossil energy consumption and CO2emissions; but on the other hand, high-density reservoirs in the river may cause cumulative effect on river ecosystem. In order to keep the river health, achieve the sustainable development, it is significative to study on the cumulative effects and GHG reduction potential of cascade hydroelectric plants.In this paper, the cumulative effects of cascade hydroelectric plants are considered, that include cumulative effects on water temperature, hydrological regime and fish. And the life cycle assessment system and methodology of hydropower plants are researched, the consumption and environmental emission of hydropower plants are discussed. The main research contents and achievements are as follows:1. Study on the environment fluid dynamic model, and river water temperature cumulative effect assessment method(1) Analyzing the temporal and spatial distribution discipline of natural river temperature, the mechanism of heat and water transfer, and the main impact factor of water temperature. Elucidating the formula of heat and water transfer flux in frozen and normal condition.(2) Improving the three-dimensional environmental fluid dynamics model to fit the reservoir water temperature calculation, the solving process and boundary conditions of the model are also researched. And the model is calibrated and verified in Ertan Reservoir. Then used in reservoir flow flied and water temperature simulation.(3) Studied on the algorithm of3-dimensional environmental fluid dynamics when applying in the reservoir with branch.(4) with the results of model simulation, studying the change of water temperature spatial and temporal distribution after the hydropower plant is built, and then assess the cumulative effects of water temperature by dam building.2. Evaluation method of rivers hydrological regime(1) Study on the natural hydrological characteristics of Yalong River. The results can provide a the basis of the comparative of hydro logic change.(2) Based on IHA indicators and RVA rivers hydrological evaluation method (WHYCOS), assessing the overall alteration of river hydrology after dam built, analyzing the key component of ecological flow. The results can provide a reference to river manager.3. Life Cycle Assessment system of the hydropower plant(1) Analyzing the inventories of hydropower plants, establishing the system of hydropower life cycle assessment. Study on the weight calculation and assessing method of environmental impact type.(2) Discussing the GHG emission of the reservoir, and analysis the GHG reduction advantage of hydropower based on the life cycle theory.This papers study on environment fluid dynamic model, assessment method of river hydrologic regime, and Life Cycle Assessment system of hydropower plant. The theories and methods of river development and ecological protection are established through the application in cascade hydropower plant. The achievement of this paper can provide an important scientific guidance to the energy planning and environmental protection in China.