Hydropower projects can actively contribute to
poverty reduction and life quality enhancement
in local communities
Hydropower is renewable because it draws its essential energy from the sun which drives the hydrologic cycle that, in turn, provides a continuous renewable supply of water. Hydropower accounts for more than 92 percent of all renewable energy generated and continues to be one of the most viable sources of new generation for the future. It also makes it possible to store energy and optimise electricity generation.
Hydropower projects can actively contribute to poverty reduction and life quality enhancement in local communities. In fact, families with little access to water and energy services are exposed to higher health risks and spend a disproportionate amount of money and time procuring these basic resources. On the other hand, access to electricity promotes new economic activities, empowers women and reduces menial domestic chores such as firewood collection. It also improves health and education services and provides a cleaner and healthier home environment, such as indoor air quality.
Hydropower can be developed on a wide range of scales to meet diverse needs and market or power conditions. While small-scale, decentralised development can bring power to remote and rural communities, large-scale hydropower infrastructure with reservoirs often provide multiple-use benefits, particularly through increased availability, reliability and quality of fresh water supplies and reduced flood risks.
Globally, there are more than 11,000 hydroelectric power plants operating in 150 countries, accounting for about 20% of total energy generation. Hydropower’s share of national power generation in Norway and many African countries is as high as 99% while in Brazil it is 84%, Venezuela 74% and Canada 59%. So far, only about 30% of global hydropower resources has been developed.
Compared to other energy sources, hydropower offers some important advantages:
hydropower is a well-proven form of power generation;
hydropower contributes significantly to the reduction of greenhouse gas emissions;
hydropower is a clean form of energy and leaves no environmentally harmful residues;
hydroelectric power generation is cost- efficient and not sensitive to fuel price increases;
in many regions of the world, hydropower reservoirs are also vitally important for water supply, irrigation, and flood protection;
civil construction work for hydropower plants creates local jobs and supports the regional economies;
hydropower conserves fossil fuel resources.
Risks and safety
The overall failure rate of dams is about 1%, but a time-related analysis shows that it has been reduced by a factor of four or more, over the last 40 years.
The precursor to dam failure is overtopping, which can be due to inadequate spillway design, debris blockage of spillways, or settlement of the dam crest. Foundation defects, including settlement and slope instability, are another cause of dam failures. “Piping”, that is internal erosion caused by seepage, is the third main cause. Other critical factors include inadequate maintenance and the structural failure of the materials used in the construction. Furthermore, natural deterioration is associated with the prolonged use of dams, consequently it is necessary to carry out specialised checks to verify their structural soundness and good working conditions.
Two of the most significant past failures were the Saint Francis Dam (California, USA) in 1928 and the Vajont Dam (Italy) in 1963. Safeguarding human life is the main motivation for the improvement of evaluation and monitoring techniques for dam safety. It is also worth remembering that these improvements can also make an important contribution towards a more effective management of the power plants so as to exploit the water resources to their maximum potential.
The growing number of dams makes it essential to evaluate rigorously the problem of their safety from a social and economic point of view. This problem is highlighted by the high density of people living downstream from the majority of the dams around the world.