دانلود رایگان مقاله نقش آب در کاهش خطر تغییر آب و هوا و انطباق

Abstract

Hydropower is a clean, renewable, and environmentally friendly source of energy. It produces 3930 (TW.h).a−1, and yields 16% of the world’s generated electricity and about 78% of renewable electricity generation (in 2015). Hydropower and climate change show a double relationship. On the one hand, as an important renewable energy resource, hydropower contributes significantly to the avoidance of greenhouse gas (GHG) emissions and to the mitigation of global warming. On the other hand, climate change is likely to alter river discharge, impacting water availability and hydropower generation. Hydropower contributes significantly to the reduction of GHG emissions and to energy supply security. Compared with conventional coal power plants, hydropower prevents the emission of about 3 GT CO2 per year, which represents about 9% of global annual CO2 emissions. Hydropower projects may also have an enabling role beyond the electricity sector, as a financing instrument for multipurpose reservoirs and as an adaptive measure regarding the impacts of climate change on water resources, because regulated basins with large reservoir capacities are more resilient to water resource changes, less vulnerable to climate change, and act as a storage buffer against climate change. At the global level, the overall impact of climate change on existing hydropower generation may be expected to be small, or even slightly positive. However, there is the possibility of substantial variations across regions and even within countries. In conclusion, the general verdict on hydropower is that it is a cheap and mature technology that contributes significantly to climate change mitigation, and could play an important role in the climate change adaptation of water resource availability. However, careful attention is necessary to mitigate the substantial environmental and social costs. Roughly more than a terawatt of capacity could be added in upcoming decades.

5. Conclusions

Hydropower is a clean, renewable, and environmentally friendly source of energy, which yields 16% of the world’s generated electricity and about 78% of renewable electricity generation (in 2015). It contributes significantly to the reduction of GHG emissions and to the security of the energy supply. In comparison with conventional coal power plants, hydropower prevents the emission of about 3 GT CO2 per year, or about 9% of global annual CO2 emissions. In general, it is a source of energy that produces few GHG emissions. Another advantage of hydropower is that it is one of the cheapest renewable energy sources, and is often economically competitive with current market energy prices. It requires relatively high initial investment, but has a long lifespan with very low operation and maintenance costs. Hydropower has among the best conversion efficiencies of all known energy sources (about 90% efficiency, water to wire). In addition, it shows high reliability, flexibility, and variety in project scales and sizes, which gives hydropower the ability to meet large centralized urban and industrial needs as well as decentralized rural needs. Hydropower, wind energy, and solar energy have important synergies, because wind and solar energies are intermittent and very variable, while hydropower is able to balance out variability and supply the peak load. In addition, hydropower is the only system that currently exists to store energy in a significant and effective way—in pumped storage power plants, which provide 97.5% of global energy storage in the electricity networks. Hydropower generation has shown increased development from the beginning of the 21st century. Trends for upcoming decades foresee a great expansion of hydropower, mainly in developing countries and emergent economies. In climate change mitigation scenarios, hydropower development has a very important role. The last IRENA REMAP 2030 scenario, which aims at doubling the global share of renewable energy, requires 2200 GW of global hydropower capacity to achieve its targets.