Wind power

What Are Renewable Energies?

Renewable energy is a type of energy that its source comes from virtually endless natural sources. Renewable resources can regenerate faster than the rate at which they are consumed.

What are renewable energies?

This type of energy is related to clean energy that does not generate greenhouse gases like fossil fuels. Therefore, on climate change, they do not contribute to global warming.

Energy efficiency varies depending on the type of energy. However, compared to non-renewable sources, efficiency is higher.

The main advantages of this type of energy are:

  • They are clean, respectful of the environment, and does not emit carbon dioxide.

  • They are safer and pose fewer health risks than other energy sources such as NPP.

  • They are an alternative to nuclear energy and the nuclear waste it generates.

  • Its sources of energy come from natural resources, so it is not depleted.

The United States produces about 11% of total primary energy consumption in the country. In domestic terms, the production of about 17% of the domestic electricity comes from renewable energy sources.

Examples of Renewable Energy

Renewable energy can be used to generate electricity and also for other uses. We attach some examples below:

  • Generation of electricity through solar panels.

  • Solar thermal energy installations for heating.

  • The heating of swimming pools using solar energy.

  • Thermal power plants using geothermal energy.

  • Heating systems using geothermal wells.

  • Generation of electrical energy through wind farms.

  • The use of hydraulic energy through swamps for the generation of electricity.

  • Sailing boats use wind power to get kinetic energy.

  • The flight of gliders and paragliders without motor, which take advantage of the updrafts of air.

  • Photosynthesis is a process that plants carry out that converts CO2 into oxygen. In this case, from solar energy, chemical energy is obtained naturally.

Types of Renewable Energies

The principal sources of renewable energy are the following:

1. Solar Energy

Solar energy is the energy that directly takes advantage of solar radiation. Although the Sun does not have eternal life, it is estimated that the life of the Sun is millions of years. We distinguish two types:

  • Solar thermal energy. Converts radiation from the Sun into heat energy. It is used to produce domestic hot water (DHW) and steam.

  • Photovoltaic solar energy. Solar panels are solar-powered engines that transform solar energy into electricity.

Solar Thermal Energy

Solar thermal energy or solar thermal energy consists of taking advantage of the Sun's energy to produce heat. It can also power an absorption refrigeration machine, which uses heat instead of electricity to deliver cold. 

Solar thermal energy directly uses the energy received from the Sun to heat a heat transfer fluid. This energy is stored and transferred to another working fluid.

Photovoltaic Solar Energy

Photovoltaic solar energy is the energy obtained by converting sunlight into electricity using a technology based on the photoelectric effect. This effect is possible because certain materials can absorb photons (light particles) and release electrons, generating an electric current.

PV systems range from small generators for self-consumption to large PV plants.

A photovoltaic cell or solar cell is a semiconductor device where this effect takes place. The most popular solar cell's material is silicon.

Solar panels supply electrical energy in a form of CC. So, often these facilities have a current investor to turn it into AC that is the most current used.

2. Wind Energy

What are renewable energies?

These systems convert the force of the wind into electricity. To do this, they use wind turbines that are windmills designed to produce electrical energy.

The wind moves by pressure and temperature differences caused directly or indirectly by the Sun. Moving breeze has kinetic energy that windmills convert into electricity.

There are two types of wind installations:

  • Isolate wind power installations.

  • Wind farms are a set of wind turbines, sell the electrical energy generated to the grid.

3. Hydropower

Hydropower takes advantage of the potential energy of water to obtain mechanical work. If we use this work to power a generator, we get electricity - hydroelectric power. Hydropower is renewable, thanks to the water cycle. 

The main advantage of hydropower is that it allows storing energy in the form of potential energy. At times of demand, the system releases this energy to generate electricity.

What Is a Hydroelectric Power Plant?

It is a power plant that uses the power of a waterfall to generate electricity. The available energy depends on the water drop and water flow.

There are power plants with a small installed flow (some 10 m3/s) but a large drop (some 100 m). On the other hand, there are also plants with a large established flow (some 1000 m³ / s) but a small drop.

Hydropower plants can be located directly in the riverbed or in an artificial canal that supplies water from the riverbed. In large falls and small flows, water to the power plant is often routed through an underground tunnel.

The amount of energy produced or the power plant's current power depends on the drop and water flow.

Hydropower plants are currently the largest producer of renewable energy in the world. They generate 16% of global electricity.

Types of Power Plants

There are two types of hydroelectric power plants:

  • Flowing hydroelectric water plants. These plants capture a part of the circulating flow through a river.

  • Hydroelectric plants at the foot of the dam. The best location for this type of plant is downstream of the reservoirs.

Hydraulic Turbines

The water presses on the turbine's rotating blades and drives an electric generator that produces electricity.

There are three types of turbines:

  • Kaplan turbine (for direct power plants)

  • Francis turbine (most commonly used)

  • Pelton turbine (for high inlet heights)

4. Biomass

Biomass plants use organic material of vegetable or animal origin. It includes the products and by-products resulting from its transformation.

We can include biofuels in this kind of source. The primary use of biofuels is transportation.

We can divide their uses into two groups:

  • Domestic and industrial applications that work through the direct combustion of biomass.

  • Uses related to the appearance of new resources and new shift techniques.

5. Tidal and Wave Energy

Seas and oceans are huge solar collectors of energy. There are several technologies to extract this power (waves, tides, and thermal gradients).

What are renewable energies?Power plants use the energy released by seawater in its upward and downward tides' movements. The plants can obtain energy by passing the water through hydraulic turbines.

Oceanic Thermal Energy

The conversion of oceanic thermal energy takes advantage of temperature differences in the sea. It is possible to obtain power from the thermal difference between the water on the surface, and at 100 m depth.

6. Geothermal Energy

Geothermal energy is the thermal energy stored in the underground layers of the Earth.

What are renewable energies?The amount of thermal energy stored inside the Earth is enormous. The use of this energy resource has practically no effect on the internal energy of the planet. For this reason, it is considered renewable energy.

A heat transfer fluid circulates through these areas to get the thermal energy. The liquid carries heat energy to the surface.

There are two primary uses of it depending on the use:

  • Geothermal power plants generate electricity using Earth's heat.

  • Domestic installations allow us to obtain domestic hot water (DHW) and heating in a home.


Renewable energy is the energy that comes from endless resources. The main advantage is that it does not emit carbon dioxide and other greenhouse gases. Therefore, it does not negatively contribute to climate change.

The primary renewable sources are solar energy, eolic energy, hydropower, biomass, tidal energy, and geothermal energy.


    Published: April 10, 2015
    Last review: November 3, 2020