Tarong's Starfish Hill Wind Farm - Jeff Ware
Jeff Ware gave a highly informative presentation on the Starfish Hill Wind Farm development at the March meeting of the SAMG. Jeff has had extensive experience in the electric power generation industry, primarily in black coal-fired stations in Queensland working for the Queensland Government's Tarong Energy Corporation. More recently he has been project manager and now operations' manager at Tarong's Starfish Hill Wind Farm development along the coastal hills south of Adelaide that can now be seen out to the west along the Delamere to Cape Jervois road.
The commissioning of the 23 wind generators at Starfish Hill that provide peaks of about 34 Megawatts into the South Australian power grid marks the beginning of wind farms in South Australia and provides a welcome alternative to the local fossil fuelled generators (mainly brown coal and natural gas) combined with interstate power feeds that SA has mainly relied upon up until now.
Of course, the "fuel" (ie. wind) is free, but there is an establishment cost of over $100 million in the case of the Starfish Hill site and ongoing maintenance costs that means it will be a while before this project pays off. Then there is the eventual generator replacement after a life expectancy of about 25 years. Fossil fuel generators are presently cheaper to establish and are more able to respond to demand when it occurs, but gaining vital experience and establishing an alternative power generation industry is being encouraged by the SA government as a better long term goal particularly as it promises to become cheaper as time goes by and provide increasingly valuable "carbon credits".
The 1.5 Megawatt wind generators, the fixed pitch wood and fibre glass 32 metre long turbine blades, the hubs, and gear boxes for Starfish Hill were made by NEG Micon of Denmark and transported to Port Adelaide by the Russian ship, Alexandrov. The 68 metres high towers were fabricated and installed by Air-Ride and SDS Ausminco in South Australia. The towers are bolted onto concrete bases that are held in place with rock anchors embedded into the hills' bedrock. The use of rock anchors significantly reduces the amount of concrete needed in the bases. Jeff said that it is hoped to do more local manufacture in future to further reduce the cost of wind farms.
Of all the various ways of generating and delivering power to a grid, the method chosen at Starfish Hill generates 50 Hz AC at about 690 volts synchronized to the mains at the top of each tower which is then transmitted down the tower on cables that wind and unwind up to 3 times in either direction under electronic control. A transformer at the base of each tower transforms the voltage to 33 kV to connect to the grid.
Jeff explained why the 3 bladed turbine design is optimum for wind generators worldwide. Two bladed designs are too hard to keep in balance and more than 3 blades make the hub and blades too big, too heavy and too expensive.
The Starfish Hill turbines use fixed pitch blades. Jeff said this was a lot cheaper than variable pitch blades and the relatively consistent nature of the prevailing winds at Starfish Hill allow fixed pitch to be used satisfactorily. Control of the generators at various wind speeds is done by varying the angle of the turbine into the wind and selecting either of the 6 or 4 pole generator windings. Mains frequency synchronization is achieved by controlling the amount of power delivered to the grid by generator field current control which, in turn, determines the load on the turbine blades which, in turn, controls the speed of the blades (11 rpm for 6 pole and 17 rpm for 4 pole).
One obvious criticism of wind generators is that they only work when the wind is blowing. Therefore sites are chosen where there are frequent, strong, steady, prevailing winds such as along Australia's southern coastline. Some power needs such as water desalination or hydrogen gas production can be done whenever wind is available, however generally our power needs are very time dependent. But, as Jeff pointed out, there is presently a considerable research effort being put into finding more efficient energy storage and retrieval methods than, say, pumping water into storage dams, charging banks of batteries, spinning up flywheels, or charging storage capacitors. If, or when, something is available then wind farms combined with such energy storage will be able to supply power in step with consumer demand. Until then wind farms will be able to contribute to, but not totally supply, our power needs. Fossil fuel will be needed for a while yet, or just maybe there's a use for all those old superconductors and bottles of liquid helium we all have lying around to provide lossless energy storage and retrieval!
A big incentive to use wind farms is their low environmental impact. Because no fossil fuels are burnt, it is estimated Starfish Hill will save about 2.1 million tonnes of green house gases over 25 years. The site was, and still is, used for sheep farming with no effect on the sheep. While there is some wind noise produced by the turbines, the level is probably less than the wind in nearby trees. There have been 2 eagle strikes at Starfish Hill since the erection and commissioning last June, but this is very unusual compared to any other sites around the world so is hoped there will be no more.
In the discussion that followed Jeff's presentation the subject of efficiency was raised. It was eventually agreed that conversion of as much of the wind power that passes through the turbine to electric power is not really what we are trying to achieve. We are really trying to get as much power as possible for the dollars spent no matter what we use to do it that is a somewhat different objective. In this respect Jeff has used the performance measurement known as "Capacity Factor" on his graphs to give a more realistic economic comparison with other sites around the world and Starfish Hill looks pretty good.
Jeff, you must be very satisfied at the successful outcome of the Starfish Hill Wind Farm project. I wish to thank you on behalf of the SA Microprocessor Group and myself for giving us much insight into this most interesting and exciting development for power generation here in South Australia.
You can read more at Tarong's web site http://www.starfishhill.com.au and make sure you look at the PDF file that can be downloaded from the front page for some amazing aerial photos of the site and a more detailed technical explanation of the system.
Also you can see my pictures of the Starfish Hill Wind Farm at http://www.adam.com.au/arem/Starfish/INDEX.HTM
Stand by for the possibility of a site visit later in 2004.