Renewable energy is usually defined as energy that comes from a resource that is naturally replenished. Some forms of energy, such as biogas from a landfill, are often considered renewable, even though the resource will eventually run out. The use of some renewable energy resources, such as geothermal energy, needs to be carefully managed so the resource does not run out.
Renewable energy sources generally emit no or very little greenhouse gas emissions when you use them, so they are better for the environment.
Examples of renewable energy include:
- Bioenergy which can be used in a number of ways to generate electricity, heat, or transport fuels from biological materials that store energy, such as wood
- Geothermal energy which can be harnessed to generate electricity or provide direct heat
- Hydro energy generated from water flowing through turbines
- Marine energy such as wave, tidal, and ocean energy devices
- Solar energy from the sun
- Wind energy which can be harnessed to drive wind turbines.
Non-renewable energy is sourced from fossil fuels like coal, oil and gas.
Once they are used, they are gone, and they emit greenhouse gases that contribute to climate change.
Renewable energy in New Zealand
Renewable energy plays an important role in New Zealand's energy supply system, with around 75% of electricity generated from renewable sources.
The amount of wind energy is still relatively small but with our world-class wind resources it is rapidly growing, while the use of wood energy and other forms of bioenergy is gaining ground in certain niches.
Nearly all transport in New Zealand relies on fossil fuels. Exceptions include electric trains and buses, and more recently, vehicles running on biofuel blends as an alternative to petrol and diesel. Electric vehicles are likely to become common in the future.
Solar energy is being used both to heat water for homes around the country and to generate electricity by means of photovoltaic panels.