So, if Australia is to cut its greenhouse gas emissions, could offshore wind power be part of the answer?
In the first six months of 2011, 101 new offshore wind turbines were connected to power grids across the UK, Germany and Norway. These turbines mean Europe now has a total of 1,247 grid-connected, offshore wind turbines with a total generating capacity of 3,294 megawatts. Roughly speaking, that generates enough electricity to power one million households.
Although this might only be a very small fraction of the total wind power capacity in Europe (roughly 4%) and an even smaller fraction of overall electricity generation, this is just the beginning. Offshore wind energy has been identified by the European Union as “a key power generation technology for the renewable energy future”.
So, if offshore wind power is the way of the future in Europe, are there good reasons why we don’t have a single offshore wind turbine in Australia? After all, it’s a technology with a number of significant benefits:
Offshore wind farms can utilise higher and less-variable wind speeds than onshore farms.
There is often more suitable (and available) space to build wind farms in offshore waters than there is on land.
Offshore wind turbines are far less visible than onshore turbines, which matters to a small minority of people.
Unfortunately, the capital and maintenance costs associated with offshore wind farms are, at present, roughly double that of onshore wind farms. However, as the offshore market expands, it’s hoped these costs will decline to the point where the advantage of higher electricity output will outweigh higher set-up and operational costs.
Why are the vast majority of the world’s offshore wind farms in Europe? Well, there are a number of reasons:
Europe is densely populated and so the amount of land available for onshore wind farms is limited.
Europe has large areas of coastal waters with a depth less than 30 metres. Current offshore technology builds the foundations of wind turbines into the ocean bottom and construction in deeper waters can be very expensive.
The European Union has a strong commitment to cutting greenhouse gas emissions, with renewable energy as a major technological solution to this challenge. The EU is therefore willing to invest in expensive offshore wind farms in order to bring their costs down as the market expands.
Germany is also relying on renewable energy, mostly wind, to replace a large fraction of its nuclear power stations which are being phased out.
Australia is in a very different situation. It still has plenty of potential sites on land, which would generate much cheaper wind power than current offshore technology.
In addition, most of Australia’s coastal waters are too deep for current wind turbine technology and it will be a long time before floating wind turbines – which are still at the pilot stage – are commercially available.
Despite these factors, there is some potential for the development of offshore wind farms in Australia.
In a research paper published in 2009, Eleonora Messali and I identified potential sites in Australia where offshore wind power may be feasible in the future. The sites had to meet a number of criteria, including:
- medium to high wind speeds;
- shallow waters;
- proximity to electricity users and the transmission grid;
- environmental and other constraints, such as marine parks and shipping lanes.
Some potential sites are located off the Western Australian coast near the South-West Integrated System (SWIS) electricity grid, while others are near the cities of Whyalla (South Australia), Gladstone (Queensland), Rockhampton (Queensland), Bundaberg (Queensland), Mackay (Queensland) and Melbourne (Victoria).
It’s hard to say how long it will be until we see the first offshore wind farms in Australia, but until the costs come down, Europe will continue to lead the way.