Luis Miguel San Martin FernandezJuan Diaz Rios Luis Miguel San Martin Fernandez and Juan Diaz Rios 2º eso A

Hydropower is a renewable energy obtained from the use of kinetic and potential energies of the water stream, waterfalls and tides.

Hydropower is one of the oldest sources of energy. It has been used for thousands of years to turn a paddle wheel for purposes such as grinding grain. The source of hydropower is water so hydroelectric power plants must be placed in areas with highest amount of water.

We find water in rivers, seas, oceans, marshes, lakes… To recover the water we have to build hydroelectric plant in marshes, dams, canals and the installation of large turbines and equipment to generate electricity.

This water is stored in dams. Part of the stored water is let out to move the blades of a turbine mesh with a power generator.

Most hydropower is used primarily to generate electricity, but some are purely mechanical. Main categories include: - Riverine hydropower: We use the hydropower of rivers - Marine hydropower: We use the hydropower of oceans, seas…  In Spain, 18.5% of energy production is hydropower. The development of hydroelectric power in Spain in recent decades has always been growing, but its share has decreased due the increase of production thermal and nuclear power. The hydraulic plant which has the largest production capacity is installed in the dam of the River Duero (Salamanca) with 1140 MW, followed by the damming of the River Tagus (province of Caceres) with 915 MW.

-Advantages: it’s a renewable energy. It’s inexhaustible and ecological. It has a low maintenance cost. And it doesn’t need any fuels so it doesn’t produce carbon dioxide. -Disadvantages: the construction of large dams can flood important tracts of land. Dams can destroy some aquatic ecosystems, for example, studies have shown the dams of the coast of North America have reduced the population of trout because they need to migrate to reproduce. A solution for this problem is to construct a type of ladder for the fishes. And also dams can cause a modification of the caudal of the river with the movement of the turbines.

The most important advantage is that there isn’t cost of fuel (so it’s also very important that there isn’t any burnings producing carbon dioxide). Operating costs are low because the hydraulic plants are automated.

Dam can obstruct the migration of some fish and change the natural water temperatures, chemistry, flow characteristics, and silt loads, which can lead to significant changes in the ecology (living organisms and environment) and in rocks and land forms. These changes may have negative impacts on native plants and animals in and next to the river. Reservoirs may cover important nature areas, agricultural land, and archeological sites, and cause the relocation of people. Greenhouse gases, carbon dioxide and methane, may also form in reservoirs and be emitted to the atmosphere, even in very small amounts. The production of the very few amounts of these gases is caused, for example, because of the breakdown of the trees that get into the river with the construction of the reservoirs.

The hydropower will be very used in the future because when the non-renewable energies are depleted, we will need to use renewable energies like the hydropower.

There are three different ways to use water to produce energy: 1º- Causing it to fall from a certain height and making it to move turbines. 2º- When water is heated it becomes steam that can produce a very high pressure, which is harnessed to move turbines. 3º- The movement of large masses of the sea’s water (waves, tides and marine currents) are also harnessed to move turbines.