Energy

Is it a really clean energy?

Anything associated with water, including hydroelectric power, gives us the idea of a clean, eco-compatible and, especially, a renewable source of energy. The impact of a large dam and its reservoir, or a hydroelectric power plant on the landscape certainly cannot be disregarded, and it is not only a matter of visual impact. An artificial reservoir (some can contain hundreds of millions of m3 of water) has very strong geological and hydro-geological repercussions. Deep water and superficial water circulation is upset, and a large number of areas are created that can generate problems with regard to stability, with consequent landslide phenomena. The network of intake channels that are necessary to transport the water from the reservoirs and from the areas in which water is collected to the power plants is often created underground, and dug inside the mountain, changing the water circulation underground, with consequences that are difficult to foresee, particularly in the karst areas. Also for large power plants there are problems connected with the environmental impact: aesthetical aspects, electromagnetic pollution and overload on the ground. The power stations in the caves, built underground, partly eliminate the aesthetical problem but the problem of the disposal of the excavation material remains, and their realization may influence underground water circulation Intake of water decreases the quantity of water in the torrents and rivers downstream from the power plant and upsets the river ecosystems, thus causing severe damages in the heritage of fish and nature. By law, it is foreseen that the water intake must not exceed a percentage of the natural capacity and what is considered a “vital minimum” must be guaranteed, so that the life of the water course and its ecosystems is protected. Actually in periods of drought, long tracts of the water courses are left practically dry, with the consequent damages to the environment.
The negative effects are not limited to parts of the river downstream from the plants but are felt along the entire water-network. A decreased flow of water in the water courses provokes a greater concentration of polluting substances in the water courses and also in the water tables that these supply. Furthermore it must be added that the plants are built in mountain areas at high levels, and often these are to be found in Parks and Natural Reserves – areas that are particularly vulnerable and that require a particular protection of the environment In Italy, in the Alps, approximately 90% of the water courses are altered due to intake-structures for hydroelectric purposes, and only 10% of the Alpine torrents is left to flow in its “natural” state. It is easy to imagine how the utilization of a source of energy that is apparently “clean” can be transformed into a source of severe environmental damage, if it is not managed in a responsible and careful manner.