Sustainable Energy Sources: Hydropower, Nuclear, Wind, and Solar

Hydropower

Hydropower utilizes the energy of water in rivers, which can be dammed to create reservoirs. These reservoirs have exit gates that lead to a turbine. The rotation of the turbine is converted into electricity. Reservoirs also serve to store water for irrigation and human consumption, and they help prevent dangerous floods.

However, hydropower has drawbacks. It can:

1. Inundate large areas of the banks.
2. Destabilize deltas (sediment that nourished these is now trapped at the bottom of the reservoir, and the sea erodes the delta).
3. Alter aquatic life.

Consequently, new hydropower plants are no longer built in many countries, and some older ones are being dismantled in more advanced nations.

Nuclear Energy

Globally, there are 442 nuclear power plants (8 in Spain), which provide 15% of the world's electricity. There are also approximately 50 nuclear submarines.

In nuclear reactors, uranium-enriched plutonium 235 is bombarded with neutrons, causing fission. This process breaks the uranium into two smaller nuclei, releasing energy. The heat generated is used to vaporize water, and the steam drives a turbine to generate electricity.

After three or four years, most of the uranium has decayed, and the used fuel must be removed. This material is hazardous for thousands of years, and there is no universally accepted solution for the safe disposal of radioactive waste. The first nuclear power plant was built in 1956, and a safe long-term storage solution remains elusive.

Wind Energy

Wind turbines are modern windmills where the movement of the blades turns a dynamo to generate electricity. This type of energy has increased tenfold in the last decade, especially in Europe. The future of wind energy lies in offshore wind farms at sea because the wind is more constant there.

However, the impact on migratory routes of birds, which can be victims of the giant windmills, must be carefully studied.

Solar Energy

Solar energy is an inexhaustible source that can be used in two ways: converting sunlight directly into electricity using photovoltaic solar panels or generating heat using solar thermal panels. In the latter case, the heat boils water, and the steam moves a turbine, generating electricity.

Solar energy is a perfect energy source for countries with intense and constant solar radiation.