Wind-energy industry checks its pulse in Adelaide

By 2020 expect wind energy costs to be 20% to 40% below current levels, more footing variations (annulus, rock anchors) to decrease costs, and grid integration such that wind farms are more like traditional generators. And expect exponential growth in machine size - four companies already have prototype 4-5MW size turbines.

Graham White, md of wind energy consultants Garrad Hassan Pacific p/l, made the predictions at Informa's Wind 2005, the two-day 4 th annual Australian Wind Energy Conference at the Stamford Grand Adelaide in February. His was one of 13 papers presented at the conference, which was organised by informa and opened by state infrastructure minister Patrick Conlon.

Noting that the industry is 25 years old, White told delegates that total expenditure to date on wind energy is $100bn, with an installed cost running at about $15bn/year. Design development, he says, will deliver larger generators, larger rotors and higher hub heights. While most turbines are 1MW to 3MW, a 3.6MW turbine is in serial production and REpower, Enercon, Prokon and Vestas are developing larger modules.

White foresees turbines with blades of carbon fibre, tower fittings attached by magnets, and a near universal transition to pitch control with variable speed for power control. Expect also a shift to offshore turbines with larger capacity. Automatic lubrication devices on the gearbox, yaw and blade bearings will achieve this. A delegate offered that he understood 12 offshore wind farms each with 30 turbines were planned in the UK over the next two years.

First 2MW turbines

The Canunda wind farm near Lake Bonney in the South East of South Australia has 23 Vestas V80-2MW wind turbines – the first 2MW turbines in the southern hemisphere. Handover of the $92.5m facility was in late March this year, and further consolidated the state as national leader in wind farm development. Canunda Power p/l, a wholly owned subsidiary of UK-based International Power owns the new farm.

Timothy Knill, construction manager for Wind Prospect p/l, the developer, gave an update on operations that emphasised the role of the “workhorse”, a 600t truck-mounted crane the biggest of its type in Australia. Moving it takes one full day for a partial disassemble for traversing within the site and up to two days when on a public road. The crane had an 84m boom for Canunda, but can be configured with longer boom lengths – up to an incredible 192m.

The Vestas V80 turbine hub height is 67m and blade radius is 40m, giving a tip height of 107m. Five heavy lifts complete the erection of each turbine – three tower sections (up to 45t per section), the nacelle (61t) and the rotor (34t) consisting of three blades and a hub.

Foundations

Knill says foundations were designed as gravity footings as ground conditions were not suitable for a design incorporating rock anchors. They were hexagonal with a plan dimension of 16m and a sloping top. Each footing contained 320m 3 of concrete and 30t of reinforcing steel. The concrete was batched just off site in a disused quarry, delivered to site and pumped into place.

5 Tassie projects

In an update on Hydro Tasmania's wind projects, Richard Mackie, manager, interstate wind development, said wind power continues to be the fastest growing energy source in the world.

Hydro Tasmania currently has five projects underway or planned: Cathedral Rocks, a 66MW joint venture with EHN near Port Lincoln, and Waterloo - 117MW 30km east of Clare (SA); Woolnorth - 140MW, Musselroe - 129MW, and Heemskirk – 160MW all in Tasmania.

Mackie said Hydro Tasmania had recorded gusts in excess of 70m/sec at Cathedral Rocks and Musselroe. On a statistical basis such gusts occur only every 50 years, and the recordings pose serious design implications. It has resulted in shorter more robust towers at Cathedral Rocks.

There was little doubt they were real events, he said, most likely caused by severe thunderstorms. High resolution, 3-D logging now accompanies normal data logging at the sites and Hydro Tasmania is working with Sydney University on wind turbine designs “to withstand these rather nasty events”.

Mackie said there was no evidence that increased wind power will drive up wholesale pool prices. “Increased supply lowers prices in a competitive market,” he said, adding that recent price rises to SA electricity consumers cannot be blamed on wind farms.

captions: Repower's 5MW wind turbine, currently the world's largest, is primarily for offshore use. Dimensions: rotor diameter 126m, tower height 120m. Power control by blade pitching.