Carbon dioxide savings

A reduction in the levels of carbon dioxide being emitted into the global atmosphere is the most important environmental benefit from wind power generation. Carbon dioxide is the gas largely responsible for exacerbating the greenhouse effect, leading to the disastrous consequences of global climate change.

Zafarana wind farm, Egypt

© Wind Power Works

Modern wind technology has an extremely good energy balance. the CO2 emissions related to the manufacture, installation and servicing over the average 20 year lifecycle of a wind turbine are generally 'paid back' after the first three to nine months of operation. beyond this, wind power produces no CO2 emissions.

The benefit to be obtained from carbon dioxide reductions is dependent on the fuel, or fuels, that wind power displaces; for example, emissions from coal for a kilowatt hour of electricity produced are higher than from natural gas. Calculations by the World Energy Council show a range of carbon dioxide emission levels for different fossil fuels. Working on the assumption that coal and gas will still account for the majority of electricity generation in 20 years' time – with a continued trend for gas to take over from coal – it makes sense to use a figure of 600 kg/MWh as an average value for the carbon dioxide reduction to be obtained from wind generation. Although this will vary from region to region, we have assumed these same average global CO2 reduction value for the regional scenarios as outlined below

This assumption is further justified by the fact that more than half of the cumulative wind generation capacity expected by 2020 will be installed in the OECD regions (North America, europe and the Pacific), where there is a strong trend for a shift from coal to gas for electricity generation. Outside of the OECD, the CO2 reduction will generally be higher due to the widespread use of coal-fired power stations.

The expected annual CO2 savings from wind energy under the reference scenario is 243 million tonnes in 2010, passing 500 million tonnes per year between 2015 and 2020, gradually climbing to 843 million tonnes per year of CO2 savings by 2030. this is small compared with the 18.7 billion tonnes of CO2 that the IEA expects the global power sector will emit every year by 2030.

Under the Moderate scenario, wind power would save the emission of a more significant 1.2 billion tons of CO2 per year by 2020, rising to 2.6 billion tonnes by 2030.

Under the Advanced scenario, by 2020 1.6 billion tons of CO2 would be saved every year, and this would grow to a considerable 3.3 billion tonnes per year by 2030– thereby saving a sixth of all CO2 emitted by the electricity sector compared with the IEA's projections.

However, it is the cumulative effect of these yearly CO2 savings that really matters to the atmosphere.

The slow growth of wind energy as envisaged by the reference scenario would mean that by 2020, wind power would have saved just 5.5 billion tonnes of CO2 globally, and this would rise to 13 billion tonnes by 2030.

A much faster growth such as the one outlined in the Moderate scenario would substantially increase the cumulative CO2 savings, by achieving reductions of 8.5 billion tonnes by 2020 and 28 billion tonnes by 2030. Under the Advanced scenario, these savings would be as high as 10 billion tonnes by 2020 and 34 billion tonnes of CO2 by 2030.

What will make a significant difference to the climate is the speed at which cuts are made. So it is not only the total emissions reductions that are of value, but it is the timing of them. Wind power's scalability and speed of deployment is a critical part of any plan to get global emissions to peak and begin to decline by 2020, which is essential to put us on a pathway where global mean temperature rise can be kept below 2°C, the most positive part of the agreement in the copenhagen Accord.

Wind farm in Spain

© Alstom