Middelgrunden Wind Farm off Copenhagen.
Under Europe’s Upwind project, a feasibility study was conducted and it concluded that 20-MW (20,000-kW) wind turbines are likely by 2020. If you’re not familiar with wind turbine sizes, this is HUGE. The standard wind turbine these days is probably 3 to 5 MW, and the ‘tremendously large’ wind turbines companies like GE, Siemens, and Vestas are working on or offering are 6 to 10 MW.
Large-scale wind turbines produce electricity far more economically than small, residential turbines for multiple reasons, but the main one is the fact that the average wind speed at a given location usually increases with altitude.
While larger turbines are more expensive to build, transport, and install, the altitude-related benefits make the trouble and expense of installing large-scale turbines worth it, because they generate electricity the most cheaply (9 cents/kWh unsubsidized, in the United States, and assuming a capacity factor of 35%, according to the NREL).
Small wind turbines often fail to pay for themselves due to unacceptably slow wind speeds at altitudes of less than 20 feet, and these turbines often being less than 20 feet tall. And because they don’t generate much electricity, they have to be oversized in order to generate enough electricity to meet demand, and oversized turbines are costly.
The 20-MW turbines mentioned above will be 200 meters (656 feet) in diameter, which is 80 meters more than traditional 5-MW turbines, which are 120 meters (394 feet) in diameter. They would also be lighter and more flexible (for their size, of course).
Significant technological advancements will have to be made, and the current design will have to change. But wind turbine developers and researchers are working on it and are optimistic.
“Making a 20 MW wind turbine is not just upscaling today’s 5 MW machines. Nevertheless, we have already identified the necessary innovations in terms of design, materials and way the turbine is operated”, said Jos Beurskens of the Energy Research Centre Netherlands, who led the Upwind project.
As big as these turbines are, they do generate far more electricity per square foot of land they occupy than smaller turbines, so they actually occupy less space overall.
h/t EVwind.es | Photo Credit: Kim Hansen
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