Renewable energy sources are considered to be inexhaustible or renewable. There are different types of power plants that use these energy sources, e.g. running water, sun, geothermal energy, wind, etc.

Since renewable energy is inexhaustible, it can be used indefinitely. This is in contrast to fossil or nuclear fuels, which are burned in power plants and cannot be used again, i.e. they are finite. For many years, attempts have been made to reduce the use of these materials, because in the long term we will have to switch to regenerative energy.

The tides are, generally considered, triggered by a heavy celestial body. On Earth, it is the moon and the sun that cause the tides. The cycle of high and low tide is called tide and repeats every 12 hours. The difference in height between low and high tide can be up to 15m.

The kinetic energy of the water, which is generated by the movement of the water, can be used in so-called tidal power plants. This form of energy is the future because it is the only regenerative energy that is completely predictable in its time of effect and strength.

Tidal energy is usable at its maximum load in over 50% of the daytime.

Wind turbines use renewable energy to generate electricity. However, wind has some disadvantages compared to tidal power plants:

• the maintenance costs and the costs of operation of wind turbines are high.
  
  
• wind is an irregular source of energy, as its occurrence is unpredictable, while tidal power plants can provide their peak load for more than twelve hours every day, wind plants can provide their peak load for only one hour per day on average
  
  
• the turbines disfigure the landscape of an entire region, while modern tidal power plants, such as the "Atlantisstrom" system, are invisible.

Hydropower is used to generate energy or to perform work. The kinetic energy of the water is used. Hydroelectric power plants such as run-of-river power plants, dam power plants or tidal power plants use renewable energy, as this energy source never runs dry.