Wind Power

2006.05.07

Discussion

Energy in the wind can be captured and turned into electricity through wind turbines, then fed into the grid to power homes, offices, factories, etc.

There are many windy places Australia that offer good prospects for electricity generation. It remains to build the wind turbines there.

Australia's electricity supply relies largely on brown coal as an energy source. While relatively cheap, brown coal is a very greenhouse gas intensive source of electricity. A large shift to wind power, replacing brown coal generators, would reduce Australia's greenhouse gas emissions substantially.

Readings

Australia's Wind Power Future

Earthbeat, 29 April 2000

Investment in green power in Australia has become far more attractive as a result of the Federal Government’s target to increase renewable energy by a further 2% by 2010. That means an additional 3000-4000 Megawatts of capacity which is about twice the size of the Snowy Mountains Scheme. The wind energy industry hopes to capture 25% of the $6-billion investment required to meet the additional 2% target.

The Australian Wind Energy Association has set itself a target that by 2002 we’ll have 100 Megawatts of installed capacity of wind energy connected to our national electricity grid. Now that contrasts from where we were at the end of 1998 where we only had 6 Megawatts installed; we’re now at 11.

Kickstarting Australia's Wind Power Industry

Earthbeat, 18 August 2001

Pacific Hydro recently launched the largest wind farm in Australia at Codrington, and they have a number of big projects in the pipeline. But the full-blown expansion of the industry will depend on manufacturing wind turbines locally.

Power from the wind

Alternative Technology Association

Wind turbines produce power from a renewable energy source - the wind.

The average sized turbine used in domestic installations is between 200 and 2000 watts, and most homes will require a turbine somewhere in this range.

Mounting a wind turbine in the right site can prove difficult. You need an area with relatively high average wind speeds, and little or no turbulence (rapid fluctuations in wind speed and direction caused by buildings, trees etc). To achieve this, the turbine is normally mounted on a high tower well above all obstructions. Tower heights range from 12 metres to 30 metres or more, depending on the site. As wind speeds increase with altitude, it makes sense to get the turbine as high as practicality and budgets allow.

Wind Energy

Australian Greenhouse Office

Wind energy is a resource which is abundant and easily accessible in most parts of the world. The southern states of Australia are well positioned to take advantage of wind energy due to their location in the Roaring Forties (the latitudes which experience consistent winds).

Modern wind turbines are very large sophisticated machines that allow the efficient conversion of wind energy into electricity. Several international companies are developing increasingly larger and more efficient wind turbines for both land and sea-based wind farms. The larger machines being developed currently have capacities as high as 3.6 megawatts, sufficient to power several thousand households with a single turbine.

Significant growth is being experienced in large scale grid connected wind farms in Australia and overseas. [In Australia, wind turbines are also being installed in remote areas, to reduce diesel consumption for local electricity generation.]

Exmouth advanced mini wind farm project

Australian Greenhouse Office

[A $225,000 grant from the Renewable Energy Commercialisation Program enabled Western Power Corporation and Westwind Turbines to develop the Exmouth advanced mini wind farm project. Three Australian designed and constructed 25kW wind turbines will] annually generate 200MWh of electricity that will be fed into the local grid, displacing the annual equivalent of 50,000 litres of diesel fuel currently consumed, which would reduce emissions of carbon dioxide by 150 tonnes per annum.

Wind power gathers speed

Australian Academy of Science

In 1996, the installed capacity of wind turbines worldwide was about 6 gigawatts – much less than 1 per cent of the global electricity generation capacity from all sources.

Advances in wind power science and technology are reducing the cost of wind power to a point at which it is becoming competitive with many other energy sources (at about 8 to 10 cents per kilowatt hour).

The power available from a wind turbine increases very rapidly with wind speed: a doubling of wind speed results in as much as an eight-fold increase in power. Therefore it is important to site wind generators in a place where the wind speed is high, as well as reasonably constant. The length of the rotor blades is also important – doubling the diameter of the circle made by the blades produces a four-fold increase in power.

Wind is slowed by friction with the land surface. Modern wind turbines are therefore mounted on towers 40-60 metres high to expose the blades to a higher wind speed. The towers themselves are simple tubular steel columns.

Recent advances in fibreglass and carbon-fibre technology have enabled the production of lightweight, yet durable rotor blades (usually two or three per turbine) between 20 and 30 metres long. These blades are capable of performing for years in the rugged conditions of some of the world's windiest locations. Turbines with blades of this length can generate up to 1 megawatt of power.

The large-scale production of wind-powered electricity involves the use of windfarms. These are concentrations of wind turbines – from just a few to hundreds that feed electricity directly into the supply network.

Bluff and bluster: The campaign against wind power

Mark Diesendorf, Online Opinion, February 2005

Wind power is one of the fastest growing energy technologies in the world. Since the industry took off in Denmark the early 1980s, it has created tens of thousands of new jobs globally and the installed global capacity has passed 40,000 megawatts (MW), generating enough electricity to power over 10 million homes.

The scenario study, A Clean Energy Future for Australia proposes that 20 per cent of Australia’s electricity could be generated from wind power by 2040.

The energy required to build a wind turbine is generated in 3-5 months of operation, so, with a 20-year lifetime, a wind turbine generates 48-80 times the energy required to construct and install it. Wind turbines are highly efficient in capturing renewable energy, since blades occupying only about 5 per cent of the swept-out area can in practice extract 30-40 per cent of the wind energy flowing through that area. As a result the material inputs to a wind farm are modest and indeed are comparable with those of an equivalent thermal power station without fuel.

Wind farms are highly compatible with agricultural and pastoral land. Their towers and access roads occupy very little land, only about 0.25-0.75 hectares per megawatt of installed capacity, leaving the rest for sheep, cattle, wheat, etc. For the same amount of electricity generated, coal-fired power stations and their mines (even underground) have much bigger impacts on land.

A Clean Energy Future for Australia

Hugh Saddler, Mark Diesendorf, Richard Denniss, March 2004

Wind Power

A wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources.

The cost of electricity from a wind farm decreases as the annual mean wind power and the size of the wind farm increase. Currently land-based wind power has an installed capital cost in some overseas countries of about US $1000/kW peak. However, a very large order (500-1600 wind turbines) can reduce the price per kW by up to 45% from the list price. Capacity factors at ‘excellent’ on-land sites are about 35% and at ‘good’ sites are 25-30%. Assuming a real discount rate of 8%, electricity from large (50-100 MW) wind farms at ‘excellent’ sites currently costs US 4-5 c/kWh. In Australia, corresponding prices, allowing for the cost of imported components, are 7.5-9 Ac/kWh.

The environmental credentials of wind power

Australian Academy of Science

The towers themselves cover only a small land area, and farming activities can continue virtually up to the base, even under the revolving blades. However, the roads needed to service the turbines take up space, as do the towers supporting connecting powerlines: the total land requirement for a wind turbine is estimated to be about 10 square metres per kilowatt of its potential power.

One problem with wind turbines is that that they produce a low-frequency drone, which increases with increasing wind speed. However, the remoteness of most windfarms means that noise isn't a major problem at most locations.

Some consider that the modern windfarm is a blight on the landscape. Turbines mounted on tubular towers are generally less of an eyesore than those mounted on steel trusses. Locals are more likely to find a windfarm attractive if they have a financial share in it, while windfarms erected without the participation of the community are less likely to enjoy local acceptance.

Wind turbines can be located out to sea (eg 20-30 km offshore), linked to the land by power cables. At sea there are fewer obstructions to air flow and less turbulence and the wind is more constant. Visual and noise impact is minimal.

Wind Farms and Bird and Bat Impacts

PDF

Australian Wind Energy Association

The impact of wind turbines on birds and bats is insignificant compared to the impact of domestic cats and the loss of habitat through development or even more dramatically, the chronic impact of ecological change due to climate change and rises in sea level induced by increased greenhouse gas emission. In Australia, collision rates are generally around one to two birds per turbine per year.

Wind farm construction and/or operation may impact the way some birds move about in a particular area. This might include direct impacts on fl ight, breeding and feeding behaviour as well as indirect impacts due to disturbance associated with construction activity and noise.

How wind power is dividing rural Victoria

Irving Saulwick, The Age, 12 July 2004

[The big wind turbines used to harvest energy in rural areas] are more than 100 metres tall. Each of the three blades is about 30 metres long. From a distance, they can look elegant. But beauty is in the eye of the beholder. To many, the turbines are a blight, an intrusion, a sore on the landscape - especially when they are perceived to be too close to where people live or when they intrude on a much-loved natural landscape. Some say they are a desecration.

The frustration of people who live near turbines is exacerbated when, because of this intrusion, they try to sell their property. They find that their land value has fallen dramatically or that there are no buyers.

Relatively small communities have, over the years, developed a social cohesion and a tolerance that is precious. People know their fellow citizens. They greet them in the street. They meet in shops or at the show or at the school fair or in those myriad other organisations that country folk have developed to express their interests and enrich their lives.

The passion over wind farms is fragmenting this social cohesion. Families are split. Friendships are damaged. Opposing camps are created. Bitterness emerges.

No Answer in the Wind

Alan Moran (Institute of Public Affairs), Herald Sun, 22 February 2003

In Victoria at least, [wind] generators are besieged by a determined and vociferous environmental lobby. The best sites for windmills tend to be exposed promontories which are often in areas of great scenic value. Even the mildest mannered nature lover tends to be irritated by a windfarm of a score or more 110 meter high behemoths emitting a steady thump-thump-thump in the wilderness or in picturesque spots.

Links

Australian Wind Energy Association

Wind Industry Development Project