What is sustainable energy?

Sustainable energy refers to energy that can be used without running out in the future. These energy sources also are called renewable energy. For example, an unsustainable energy source is oil because it will eventually run out. The good news is that there are a lot of great sustainable energy sources out there. Mostly these sustainable resources use what is already out in our environment or our waste to generate energy. Here are just a few examples of some sustainable energy out there.

Solar Power

One of the most popular sources of renewable energy, solar power is used throughout the world already. However, solar panels that are used are not necessarily super efficient... yet. People are researching not only how to make solar panels more efficient, but also how to print solar panels easily and cheaply (even on sheets of paper!) and how to use solar on homes and in work places. The interesting thing about solar energy is that you don't need a bright, sunny day for it to work. Germany is one of the leading solar power producers in the world and they have more than their fair share of cloudy days.

Currently, there are devices on the market to allow people to power laptops, cellphones, and more via mobile solar panels. Some even suction to windows; others include solar panels embedded in clothing or backpacks. Solar energy is an attractive renewable energy source for the future.

Wind Power

Wind power is another very popular source of renewable energy. Most people know about solar or wind power as renewable energy sources. Windmills have powered water wells and other mills in the past. Shiny white wind towers are springing up across the world in the most unlikely places. Wind-swept plains in Texas and windy coastal areas have both seen windmills pop up.

Wind power doesn't necessarily only come from tall windmills either. New devices are making wind energy as easy to capture as placing fan-like windmills on the side of a house or apartment.

Tidal Power

Think of tidal power sources as underwater windmills – that's basically how they work. Instead of wind, they generate power by rapidly-moving water. This energy source isn't widely used yet, but is thought to be more consistent than either wind or solar power.

Geothermal Power

A person gets power from geothermal energy by taking it out of the earth in a natural way. It can be done to give heat to a home or produce energy on a wider scale in a geothermal power plant. People have used a more basic form of geothermal energy to heat their homes and baths in ancient times. It used to be limited to areas that were near edges of tectonic plates, but new technology has changed that. Costa Rica, for example, has gotten more than 15% of its energy from geothermal power since 2004. The only downside to geothermal energy is that drilling for it can be expensive. However, the profits from geothermal can outweigh the risks and costs because a large geothermal power plant can power whole cities.


Biomass is a lesser-known renewable energy source. Only about 0.5% of energy used in the US comes from biomass. Basically, biomass refers to living or recently dead biodegradable waste, such as dead trees or wood chips, and types of plants like sugarcane, willow, poplar, hemp, and corn. The great thing about biomass is that it keeps byproducts that would otherwise be waste out of landfills.