By George Drayson – Expedition 8848 Education Team
Climate Science Series
What is Renewable Energy?
Renewable Energy, also known as clean energy, is energy made from resources that will never run out, like wind, water and sunlight. It is a clean form of energy because it doesn’t deplete the earth’s resources and at the same time doesn’t pollute our atmosphere. This is the opposite of coal, oil and natural gas.
What are the 5 main types of Renewable Energy?
Light consists of small particles called photons. When electrons absorb photons, it causes them to move to higher energy levels. If this energy is high enough, they will leave the atom.
This phenomenon is the basis for solar power:
- Light is incident on a solar panel
- The electrons absorb energy from the photons causing them to leave their atom
- This flow of electrons causes an electric field, which is converted into electricity
Solar energy can also be used in something called a solar thermal system to warm domestic hot water.
Wind pushes a turbine, converting its kinetic energy into the mechanical energy of the spinning turbine. We can then use this energy to pump water or to turn a generator, which converts this mechanical energy into electricity.
Biomass is organic material stored in plants caused by the photosynthesis of light. This biomass has stored energy, which can be released by combustion. One of the issues with this is that the use of trees and other plant material causes deforestation.
On the other hand, by using substances such as animal manure, waste food and waste wood chippings, we are not chopping down living plants and therefore not contributing to deforestation. At the same time, by switching from coal to biomass we are reducing the net carbon dioxide released into the atmosphere, which causes the greenhouse effect.
The most common type of hydroelectric power uses a dam to store water in a reservoir.
The dam releases the water through a turbine, converting the gravitational potential energy of the water to the kinetic energy of the turbine. This is then connected to a generator, creating electricity.
Geothermal energy is the thermal energy contained within the Earth’s surface.
- Water is pumped down to hot regions below the Earth’s strata,
- The water is heated and turns into steam
- The steam rises, drives a turbine, which drives a generator -> generating electricity.
Geothermal energy is a very important resource in volcanically active places such as Iceland.