Renewable energy is no longer an insignificant subset of the global energy economy. Renewable energy is now the fastest-growing source of energy in the world1, and its use is on the rise across all continents. Renewable energy sources supply electricity to hundreds of millions of people and generates hundreds of billions of dollars in economic activity2.
So, what is renewable energy?
Renewable energy is energy produced from sources that can naturally replenish themselves over time. The most common of these sources are solar, wind, hydro, geothermal and biomass energy.
Here are the key renewable energy facts you should know:
Solar Energy Facts
As its name suggests, solar energy is the energy generated from the sun’s radiation by means of photovoltaic (PV) cells. When sunshine hits the PV cell, the photons of light prompt the electrons in the cell to move, thus generating electricity.
The most abundant energy source on Earth, solar energy is also the second fastest-growing renewable energy sources today. It is used widely both in residential and commercial applications.
Fun Fact: The first silicon solar cell was actually made by Bell Laboratories in 1954. It became the precursor of all modern solar-powered devices.
Wind Energy Facts
Wind energy technologies generate either mechanical or electrical power by using the kinetic energy of the wind. Mounted high above the ground to capture the strongest winds, an electricity-generating wind turbine rotates its blades to spin an electric generator that, in turn, produces electricity.
The fastest-growing source of electricity in the world, according to a recent report by the International Energy Agency, wind is also one of the oldest renewable energy technologies, dating back as far as 5,000 BCE when the first wind-propelled boats sailed along the Nile River.
Today, wind energy is largely used in utility-scale applications by means of giant wind turbines that are usually located in relatively remote locations, including offshore, where winds are the strongest. However, small wind systems are also used by homeowners and farmers to generate electricity in particularly windy areas.
Fun Fact: Wind power available for generation is proportional to the cube of the wind’s speed, which means that a wind generator can produce eight times more power every time the wind speed doubles.
Hydropower definition: Hydropower is energy derived from the kinetic force of flowing water. It can be harnessed from river, wave or tidal movement, as well as from the water stored in dams.
Hydropower is one of the cheapest energy sources currently available. Similar to wind energy, hydropower plants use turbines and generators to convert the mechanical energy into electricity. As of 2016, hydroelectric generation accounted for 43.6 percent of all renewable electricity generation in the United States, and 6.5 percent of the nation’s total electricity generation.
Fun Fact: All 50 states generate electricity from hydropower, with Washington State deriving as much as 70 percent of its electricity needs from water.
Geothermal Energy Facts
Geothermal power plants use underground reservoirs of hot water to generate clean renewable energy. Naturally heated by the Earth’s core, these bodies of water can be located a mile or even deeper underground. By drilling deep wells to tap into these reservoirs, geothermal wells can bring steam and hot water to the surface and harness it for a variety of applications, including electricity generation, heating and more.
In the United States, geothermal energy is responsible for less than one percent of total electricity production. However, countries like the Philippines, Iceland, and Kenya generate a much larger percentage of their electricity from geothermal power plants at 14, 29, and 47 percent respectively.
Fun Fact: In some parts of Iceland, hot water from geothermal power plants is routed under roads and pavements to help melt ice.
Bioenergy is derived from biomass — organic energy sources that include plants and animals. In order to produce energy, biomass can be burned or turned into biofuels such as ethanol, biodiesel or biogas that then can be burned as fuels.
While biogas is produced from the decomposition of waste in landfills, as well as by processing sewage and animal manure, biodiesel is made from vegetable oils and animal fats. Meanwhile, ethanol is produced through fermentation of certain crops, such as corn and sugarcane. Both ethanol and biodiesel can be used as fuel in specially modified vehicles.
In 2017, biomass fuels accounted for about five percent of total primary energy use in the United States.
Fun Fact: Located in Severn Gorge, United Kingdom, Ironbridge is the world’s largest biomass power plant and is capable of producing 740 MW of power.
Interested in a renewable energy career? Learn more about Ecotech Institute’s practical, hands-on training in wind energy, solar energy, power utility and electronics technology.