Winds of change fail to sweep up Gillard

The photo opportunity of Julia Gillard at a Crookwell wind farm did not go exactly as intended.

Richard Farmer

Crikey political commentator

Removing the ugliness of wind power. The photo opportunity of Julia Gillard at a Crookwell wind farm did not go exactly as intended. Sure the pictures of an alternative to carbon spewing power stations were there but so were the opponents of these giant wind turbines. Environmentally sound they may be but the turbines are an aesthetic nightmare and a noisy nuisance to many living close to them. The federal government's $10 billion investment in the greater use of renewable energy is not a sure fire vote winner when it subsidises rural ugliness. The president of the NSW Landscape Guardians, Humphrey Price-Jones, who the Sydney Morning Herald reports, lives near Crookwell and the site of a planned wind turbine, has lobbied the government to suspend all development applications for wind farms until any noise-related health risks are assessed. It was views like his that took some of the gloss off Ms Gillard's visit. Perhaps a solution for the Prime Minister would be to divert some of renewable energy dollars into supporting an apparently promising wind power alternative under development at Caltech University in the United States. There the boffins are working away on a new form of wind turbine that's nowhere near as destructive as the present monsters. Looking something like egg beaters these turbines stand only 10 metres high and a placed much closer together than those on the spread out wind farms of today.

A report in the currently online version of the Journal of Renewable and Sustainable Energy titled "Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays" is introduced in this way:
"A principal challenge for all forms of renewable energy is that their sources -- solar radiation or wind, for example -- are more diffuse than fossil fuels. As a consequence, existing renewable energy technologies require substantial land resources in order to extract appreciable quantities of energy. This limitation of land use is especially acute in the case of wind energy, which currently faces an additional constraint in that conventional propeller-style wind turbines (i.e., horizontal-axis wind turbines; henceforth, HAWTs) must be spaced far apart in order to avoid aerodynamic interference caused by interactions with the wakes of adjacent turbines. "This requirement has forced wind energy systems away from high energy demand population centers and toward remote locations including, more recently, offshore sites. It has also necessitated the implementation of very large wind turbines, so that the inefficiency of the wind farm as a whole can be compensated by accessing the greater wind resources available at high altitudes. However, this solution comes at the expense of higher engineering costs and greater visual, acoustic, radar, and environmental impacts. These issues represent a principal barrier to the realization of wind energy technology that is both economically viable and socially acceptable. "To maintain 90% of the performance of isolated HAWTs, the turbines in a HAWT farm must be spaced 3–5 turbine diameters apart in the cross-wind direction and 6–10 diameters apart in the downwind direction.1,2 The power density of such wind farms, defined as the power extracted per unit land area, is between 2 and 3 W m−2 "Wind turbines whose airfoil blades rotate around a vertical axis (i.e., vertical-axis wind turbines; henceforth, VAWTs) have the potential to achieve higher power densities than HAWTs. This possibility arises in part because the swept area of a VAWT rotor (i.e., the cross-sectional area that interacts with the wind) need not be equally apportioned between its breadth -- which determines the size of its footprint -- and its height. "By contrast, the circular sweep of HAWT blades dictates that the breadth and height of the rotor swept area are identical. Therefore, whereas increasing HAWT rotor swept area necessarily increases the turbine footprint, it is possible to increase the swept area of a VAWT independent of its footprint, by increasing the rotor blade height. ... The power density of the VAWT design is more than three times that of the HAWTs, suggesting that VAWTs may be a more effective starting point than HAWTs for the design of wind farms with high power density. "The turbine power densities indicated ... are not achieved in practice due to the aforementioned spacing requirements between the turbines in a wind farm. However, we hypothesized that counter-rotating arrangements of VAWTs can benefit from constructive aerodynamic interactions between adjacent turbines, thereby mitigating reductions in the performance of the turbines when in close proximity. By accommodating a larger number of VAWTs within a given wind farm footprint, the power density of the wind farm is increased. "Furthermore, by capturing a greater proportion of the wind energy incident on the wind farm footprint, it becomes unnecessary to use wind turbines as large as those commonly found in modern HAWT farms. In turn, the use of smaller turbines can reduce the complexity and cost of the individual wind turbines, since the smaller wind turbines do not experience the high gravitational, centrifugal, and wind loading that must be withstood by large HAWTs. The less severe design requirements can enable the implementation of less expensive materials and manufacturing processes."
There's a long way to go from this initial small scale testing to a proven new style wind farm but the picture below shows one benefit there would be from success:

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