What is renewable energy?
Renewable energy comes from sources that will not run out, such as the sun, rivers, plants and wind. These can all be used to produce power for homes and industries, or fuel for transport.
What is non-renewable energy?
Non-renewable energy comes from coal, gas and petroleum. The earth has only a limited amount of these. They are known as fossil fuels, and they produce gases that create a greenhouse effect, causing global warming.
Renewable energy in New Zealand
New Zealand has many rivers, lakes and geothermal (hot) springs. They are used to produce nearly two-thirds of the country’s electricity. But river and lake levels may drop, leading to power cuts, so scientists are looking at new forms of energy. Compared to many countries New Zealand has plenty of wind and sunshine, but these are not yet used on a big scale.
The wind can be used to drive turbines that generate electric power. In 2004, 1% of New Zealand’s annual energy production came from wind. This was produced mostly from two ‘farms’ in the windy Tararua Ranges north of Wellington: the Tararua wind farm, with 103 turbines, and the Te Āpiti wind farm, with 55 turbines. Together they produce enough power for 75,000 homes.
More wind farms are planned. There are rules to keep the noise levels acceptable, but some communities are concerned that the turbines would spoil the landscape.
Solar energy (energy available from sunlight) is the most abundant form of renewable energy. New Zealand homes receive 15 to 30 times more solar energy than they are using in electricity and gas. This solar energy can be used to heat water, or converted to electricity.
Heating water is the biggest part of a household power bill. In 2004 less than 2% of New Zealand homes used solar-powered water heaters, but interest is growing. Special panels on the roof trap sunlight, and then heat water that runs through them and into the water tank. Because the sun is not always shining, people still need to use other water heating as a back-up.
Around the country, solar power is also used for lighthouses and electric fences.