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Renewable energy from wind power

Renewable energy from solar power

Renewable energy from biomass and biofuel

Renewable energy from geothermal heat pumps

Renewable energy from hydro power

What is renewable energy?

Renewable energy can be used to produce electricity, generate heat and transport goods and people. Renewable energy is energy that is essentially inexhaustible. Renewable energy is energy generated from natural resources such as sunlight, wind, flowing water and replaceable fuel such as plants.

Renewable energy is energy generated from natural resources like wind, radiation from the sun and heat from within the earth. Such energy will not run out and can be used to generate electricity. Unlike the burning of fossil fuels that emit carbon dioxide into the atmosphere, these ‘clean’ energies do not release substances that are harmful to the environment.

Renewable energy technologies include solar power, wind power, hydroelectricity, and biofuels.

"Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources."
The International Energy Agency

Here is a brief outline of the different types of renewable energy. Please see the menu on the left for a more detailed explanation of each type.

Wind Energy
Wind energy is the kinetic energy that is present in moving air. This kinetic energy of the wind can be changed into other forms of energy such as mechanical energy or electrical. Wind energy is a pollution-free, infinitely sustainable form of energy. It doesn’t use fuel, it doesn’t produce greenhouse gasses and it doesn’t produce toxic or radioactive waste.

Solar Energy
Solar energy refers to the utilisation of energy from the Sun. Solar energy can be converted into other forms of energy, such as heat and electricity.

Solar energy can be applied in many ways, these include:
Solar panels – Solar panels are an ideal source of renewable energy as it is pollution free. Solar panels produces electricity quietly unlike the energy produced from the use of fossil fuels and some other types of renewable energy which can be noisy.

Solar energy enables electricity to be produced in remote locations that are not linked to a national grid.


Biomass
Biomass is produced from organic materials derived from living organisms or from metabolic by-products (organic or food waste products) such as wood, woodchips, paper, trash, agricultural crops, animal waste, manure, sewage, hemp and algae.

Biomass contains stored energy from the sun as plants use photosynthesis to grow and produce biomass.

When burned, the chemical energy in biomass is released as heat. If you have a fireplace, the wood you burn is a biomass fuel. Wood waste or garbage is burned to produce steam for making electricity and to provide heat to industries and homes.

Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel and ethanol can be burned in internal combustion engines or boilers.

Biofuels
Biofuel is any fuel derived from biomass. Biofuel is a renewable energy source. The two types of biofuels are ethanol and biodiesel. Biofuels can help reduce air toxics emissions, greenhouse gas build up and dependence on fossil fuels. Biofuels are commonly used to power vehicles and cooking stoves.

Biofuels offer the possibility of producing energy without a net increase of carbon into the atmosphere because the plants used in to produce the fuel have removed CO2 from the atmosphere during growth, unlike fossil fuels which return carbon which was stored beneath the earth’s surface for millions of years into the air. Biofuel is therefore more carbon neutral and less likely to increase atmospheric concentrations of greenhouse gases .The use of biofuels also reduces dependence on petroleum.

Hydroelectricity
Hydroelectricity is a form of hydropower and is the most widely used form of renewable energy. It produces no waste and does not produce carbon dioxide (CO2) a greenhouse gas.

Hydroelectric power is generated by harnessing the power of moving water. Hydro electricity extracted from water depends not only on the volume but on the difference in height between the source and the water's outflow.

Hydro power systems convert potential energy stored in water held at height into kinetic energy movement to turn a turbine to produce electricity.

Geothermal Heat Pumps
Geothermal heat pumps (GHPs) use the constant temperature of the earth as the exchange medium instead of the outside air temperature
A geothermal heat pump uses the Earth’s ability to store heat in the ground and water thermal masses to produce heating or air conditioning.

These systems operate based on the stability of underground temperatures: the ground, a few feet below surface has a very stable temperature throughout the year depending upon the location's annual climate. A geothermal heat pump uses the available heat in the winter and puts heat back into the ground in the summer.