Hydropower environmental impact

Hydro-electricity is the most developed renewable resource worldwide, even if it has to face social and environmental barriers [29]. In fact societal preferences are difficult to predict, while hydro-sites are often difficult to reach, which results in high transmission and capital investment costs. These are difficult to be accepted by private power companies. The global economic hydropower potential ranges between 7000 and 9000 TWh per year. Particularly mral communities without electricity appear to be convenient for small (<10 MWe), mini- (<1 MWe), and micro- (<100 kWe) scale hydro schemes. They have low environmental impacts, and generation costs are around 6-12 c/kWh. Emissions of GHG linked with hydro-electricity operation are due to flooding of land upstream of a dam that can imply a loss of biological carbon stocks and can produce methane emissions due to vegetation decomposition. 

Hydropower use for electricity generation is responsible for a wide array of enviromnental disturbances to river systems. Over the past decades, aquatic science research has been successful in identifying a considerable number of relationships that exist between plant operation and ecosystem quality. This increase in scientific knowledge was, however, not matched by a corresponding reduction in environmental impacts stemming from hydropower. One of the major reasons for this situation is that political, economic, and social aspects are neglected in purely scientific assessments of environmental impacts. 

The situation may be illustrated well by the development of the public discourse on hydropower in Switzerland over the past few years. As 60% of Swiss electricity generation stems from hydropower, its environmental impacts have time and again raised political debates over the past 50 years. More recently, the liberalization of electricity markets has opened up new windows of opportunity for the development of new approaches of mitigation. One example of an integrative concept was developed by an interdisciplinary team of researchers in the late 1990s. It has been implemented in the currently operating eco-label for sustainably produced electricity in Switzerland (naturemade star). 

Developing integrated approaches for the mitigation of environmental impacts from hydropower thus has proven to be a highly challenging task for environmental... 

There have been a number of studies on fuels used for electricity generation. One of these studies focuses on the use of natural gas, heavy oil, or coal in cogeneration of electricity.112 Using a numerical eco-load total standardized evaluation system, these authors found that coal had the lowest eco-load of all alternatives considered. In another LCA study, Goralczyk113 compares hydroelectric, photovoltaic cells, wind turbines, oil, coal, and natural gas and quantifies that electricity from hydropower had the least environmental impact. Schleisner114 focuses on wind farms in a life-cycle inventory study that focuses on the materials used to manufacture the windmills and reports that 2% of the electricity generated during the windmill s lifetime is used to manufacture the windmill components. 

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