In the early 2000s New Zealand’s energy came from fossil fuels such as oil, gas and coal, and from renewable sources – water, geothermal energy, wind and solar power, and wood. In 2008 primary sources of energy were:
- oil – 37.7%
- gas – 22.6%
- geothermal power – 12.5%
- water (hydroelectricity) – 11.3%
- coal – 9.2%
- other renewable energy, including biogas, wind, wood and solar power – 6.7%.
How much coal, gas or oil equals a petajoule? It depends on chemical make-up. One petajoule is the energy from 44,740 tonnes of sub-bituminous coal (the sort most commonly used in New Zealand), about 25 million cubic metres of gas from the Māui gas field, or 28 million litres of regular unleaded petrol. No matter how electricity is generated there are 278 gigawatt-hours of electricity to a petajoule.
New Zealand’s annual energy use was not measured until the 20th century. In 1924 it was 86 petajoules (a measure of energy). By 2000 it was 772 petajoules. A much larger population and an industrialised economy demanded more energy.
Oil, and electricity produced from oil, coal, natural gas, geothermal power and water, became the dominant energy sources in the 20th century. After the First World War use of petrol and diesel transport and a growing range of electrically powered appliances became widespread. New Zealand’s manufacturing and industrial sectors were increasingly mechanised. From the late 1950s some very heavy power users were set up, such as fossil fuel-fed power stations and steel and aluminium smelters.
Government and energy distribution
The building of reticulation systems like power lines and the distribution of energy has been undertaken by private companies, local authorities and central government.
In the late 19th and early 20th centuries energy use was encouraged and controlled by local authorities and private companies. They were the suppliers of oil products, electricity, coal and coal gas. From the 1920s there was increasing government regulation of the energy sector. This was reversed in the 1980s and 1990s when successive governments removed controls in a bid to bring greater efficiency to the sector through competition. In 2007 energy was supplied by private companies, consumer trusts, municipally owned operations and state-owned enterprises.
Energy and climate change
At the end of the 20th century predicted climate change forced a new assessment of energy use and the resulting generation of greenhouse gases. The energy sector – including transport, electricity generation and heating – produced almost half of New Zealand’s greenhouse gas emissions in 2006, and was the fastest growing source of greenhouse gases, increasing emissions by 45% between 1990 and 2006.
New Zealand’s response to climate change varied from one government to the next. The 1999–2008 Labour-led government introduced mandatory targets and an emissions trading scheme. The National government elected in 2008 reopened the debate about targets.