Wind energy plays an important, global role in addressing climate change.
Wind-generated electricity is produced without emitting carbon dioxide, the greenhouse gas that is the major cause of global climate change. The lifecycle emissions (including manufacturing of components, construction, operation and decommissioning) from wind farms are about 1% of emissions from thermal generation.
In addition, wind farms are far more efficient than thermal stations. Within six months a wind farm will produce more energy than it will use in its entire lifetime. In contrast the efficiency of a thermal station is about 50% – meaning it will use about twice as much energy as it produces in the form of electricity. Using coal or gas to generate electricity creates a lot of heat that cannot be easily used for generating electricity.
New Zealand has ratified the Kyoto Protocol and so must take steps to reduce its greenhouse gas emissions. The Kyoto Protocol is an international treaty that sets out to reduce the emission of greenhouse gases that cause climate change. Between 2008 to 2012 New Zealand is required to reduce its greenhouse gas emissions to an annual average equal to or below its 1990 emissions level, or to take responsibility for the excess emissions.
We can reduce our greenhouse gas emissions by increasing the proportion of electricity that is generated from wind and other renewable energy sources.
Essentially, every unit of electricity produced by a wind farm is one unit that does not need to be produced by a coal or gas power station. By building more wind farms we can avoid investing in coal and gas fired power plants. For the existing thermal stations, greater wind generation will enable us to make more judicious use of limited gas reserves.
Electricity generation and emissions
Electricity generation is one of the fast growing sources of greenhouse gas emissions in New Zealand. Between 1990 and 2006, greenhouse gas emissions from electricity generation increased by approximately 138 per cent.
Emissions from electricity generation will continue to grow unless we take action now to increase the use of renewable resources. New Zealand has a plentiful supply of renewable energy sources that can be harnessed to generate clean, low emissions electricity.
New Zealand generates about 60-70% of our electricity from renewable resources, with the majority coming from hydro. This proportion has been dropping as new coal and gas generation has been built over the last 20 years to meet growing demand. Diversifying our electricity generation to make greater use of wind energy and other renewables will enable us to have a reliable supply of electricity as well as reduce emissions from fossil fuel generation.
Balancing global and local impacts
While the effects of a wind farm on the local environment should not be played down, they must be viewed in the larger context of the broader threats posed by climate change.
Climate change poses a significant threat to biodiversity. However, for some species the loss of a habitat or the death of a few individuals can have a major impact. For this reason, global benefits and local impacts of wind farms must be balanced on a case-by-case basis.
The impact of a wind farm on the local environment is usually minimal as most of the land with in a wind farm site is not affected and developers can avoid areas with high environmental or ecological values. The area occupied by wind turbines, roads and other structures in a wind farm is small – typically 1 to 3% of a wind farm site.
In addition, wind farm developers are often able to integrate beneficial local environmental measures into their construction and operational activities. These can include the monitoring of bird and bat populations, planting indigenous plants, protection of native bush areas, pest and weed management or erosion control.
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