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Using one of the world’s most powerful computers plus its experts in air flow and weather, Vestas forecasts the wind at site level, giving investors a security of knowing long-term economic return

Vestas uses a team of specialists in weather and airflow to determine how the wind moves through a new site for wind turbines. They provide the scientific foundation to help determine that the most suitable turbine is built in the optimal position at each site - and that the turbine will generate as much energy as possible under minimal loads.

“We can see if there’s too much wind, too little wind, too much turbulence,” says meteorologist Line Gulstad, manager of Global Flow Solutions in the Wind & Site Competence Centre, Technology R&D.
Gulstad’s team, Global Flow Solutions, consists of meteorologists - who are experts in large-scale and meso-scale weather forecast modelling - and fluid dynamicists, who model air flow on small scales, down to specific metres.

“The fluid dynamicists  look at wind flow within a site, and the meteorologists model wind in a large area,” Gulstad says. “We are the water and they are the drops.”

Vestas collects as much data as possible onsite about the wind and its properties - speed and direction, how gusty it is, how it changes speed with altitude (wind shear), and other factors.

“Everything impacts the energy production -- and how long the turbine will last,” she explains.

“The more knowledge we put into the process as early as possible at what’s really happening at site level, we will reduce the cost of energy and increase the business case certainty,” she says. “When we know all the aspects of a project as early as possible, we reduce the risk for the customer and for ourselves. We help provide the knowledge base for business decisions.”

Her colleague, meteorologist Mark Žagar, adds, “We’re accounting for what’s most important in the wind business, and that is the wind.”

Specialised weather report

From her PC at Vestas headquarters in Randers, Denmark, Gulstad displays a colourful weather map of Europe, then zooms in to the Horns Rev Offshore wind farm, where eighty, 2 MW Vestas V80 turbines operate off the west coast of Danish Jutland. She is demonstrating another advantage of collecting weather data at individual wind farms.

“We see the four-day weather forecast for this site - wind speed and wind gusts, risk for lightning, wave heights,” explains Gulstad

“This is a tool that service technicians can use,” she says. If a forecast shows strong winds, gusts or high waves at a turbine, then Vestas service technicians know to wait to go near it. On the other hand, they can look for low- or no-wind days when a turbine will not be losing the production.

Vestas Weather is currently being tested at several sites in Europe, and Gulstad expects it to be available for the whole internal Vestas community and some customers by 2010 -- that is, Vestas-generated weather reports at any Vestas site anywhere in the world.

A national weather service provides the same kind of forecast, but there is a big difference. “We combine meteorological institutes’ data with observations that come directly from Vestas turbine sites,” says Žagar. “Our forecast is superior to a regular weather forecast -- we have more information specifically meant for Vestas use.”

Supercomputer

Jetstream lies at the heart of this network. This colossal computer is eight metres long and two meters high, the machine contains 1,344 processors at 3.33 GHz that can solve multi-dimensional problems -- on par with the supercomputers used by national weather centres. “When we bought ours last year, it was 372 on the Top 500 list of biggest computers in the world,” Gulstad says.

Such computing power is necessary to crunch all the data needed for accurate forecasts. “The quality of the forecasts depends on the quality of the measurements and the quality of the model,” she says.
“To start a model, you need to be as close to the present state (of the atmosphere) as possible -- temperature, clouds, radiation, wind, all this stuff,” she continues. “If you have uncertainty in the start, it will grow incredibly large, given sufficient time.”
 

Wind forecasting increases business case certainty