Renewable Energy 101 | National Geographic

Around the world, renewable energy use is on the rise, and these alternative energy sources could hold the key to combating climate change.

What is renewable energy? Renewable energy is generated from sources that naturally replenish themselves and never run out. The most common sources are solar, wind, hydro, geothermal, and biomass. Over 80 percent of the total energy consumed by humans is derived from fossil fuels; however, renewables are the fastest-growing source of energy in the world.

Renewable energy has many benefits. First, it can combat climate change because it creates no direct greenhouse gas emissions. The only emissions that they produce are indirect, meaning those that result from manufacturing parts, installation, operation, and maintenance, but even those are minimal. Second, renewable energy can decrease pollution and therefore reduce threats to our health. Wind, solar, and hydroelectric systems create no air pollution emissions, and geothermal and biomass energy systems' emissions are much lower than non-renewable energy sources.

Third, renewable energy is a reliable source of power because renewable energy sources are, well, renewable; they will never run out. Once built, renewable facilities cost very little to operate, and the fuel is often free. As a result, renewable energy prices tend to be stable over time.

While renewable energy has many advantages, it is not without downsides. It is difficult for renewable energy sources to generate power on the same large scale as fossil fuels. Building wind farms and dams can disrupt wildlife and migration patterns and lead to ecological destruction. Both solar and wind energy are intermittent; they only generate power while the sun is shining or while the wind is blowing. Batteries can store excess energy for later use; however, they are often costly.

While renewable energy presents some challenges, it also offers an environmentally friendly alternative to the greenhouse gas emissions and pollution of fossil fuels. And as advances in technology make renewable energy more accessible, affordable, and efficient, an end to climate change could be within our reach.