Hydropower is a pillar of sustainable energy Hydropower is renewable energy that is obtained from the movement of water through storage and drop systems, and through which electricity is produced. Are hydropower, hydroelectric and hydro the same thing? Water-generated energy may have different names – hydropower, hydroelectric and hydro –but they’re the same thing and refer to the world's most important renewable source. Indeed, according to the International Renewable Energy Agency (IRENA), hydropower plant capacity is now greater than that of all other forms of renewable energy: wind, solar, geothermal, etc. When and by whom was this renewable energy invented? Water is one of the oldest renewable energy sources harnessed by humankind. The ancient Egyptians, Greeks and Romans used it to grind grain or for other mechanical tasks: there is no specific inventor or discoverer. The first real hydroelectric power plant went into operation on the Fox River in Appleton, Wisconsin, USA in 1882. How do power plants work and how is energy generated? A hydroelectric power plant is able to transform the energy associated with the movement of a watercourse into electricity This is all thanks – in most cases – to dams that channel water into large basins and drive turbines. The rest is done by an alternator, which is a machine that generates electric current from mechanical motion. In addition to large plants, there are also smaller ones, such as those for household use. Hydropower plants, examples around the world The world's largest hydroelectric plant is the Three Gorges Dam in China, on the Yangtze River. The plant has an electrical generating capacity of 22 gigawatts and a height difference of about 180 meters. Other mega-plants include: The Itaipú Dam, on the Brazil-Paraguay border. The Xiluodu Dam (also) in China The Guri Dam in Venezuela. Italy is home to one of Europe’s largest hydropower plants: this is the Luigi Einaudi plant in Piedmont. Construction work began in 1969 and it went into operation in 1982. The environmental impact of water energy Water has characteristics that make it unique: it is a free resource, is almost unlimited in terms of time and can be found almost everywhere in the world. Technological innovation has made it possible to create increasingly efficient plants that are capable of making the most of this resource. All this with minimal environmental impact and without emitting CO2 into the atmosphere. Hydropower plants are also useful for protecting the environment and biodiversity. Plants have, for example, been built in strategic locations to encourage the repopulation of certain species of fish and mammals. Furthermore, it is not uncommon for ramps to be built at hydropower plants in order to guarantee the passage of wildlife. Dams prevent the flow of branches, trees or other potentially dangerous objects, while reservoirs act as water reserves for agriculture and consumption. Through thorough hydrogeological analyses, new plants are built safely and with respect for the land. A useful reflection on water and hydropower Water is considered the ultimate renewable source, but the amount of fresh water available on the Planet (about 2.5% of the total) declines every year. That is why it is essential to preserve it, avoiding waste and promoting equitable distribution around the world.
