Think-tank boss: Turbines need to get smarter for sector to progress

The future of onshore wind power will be technologically driven — but not in the way many think — as the industry angles to get more from the resource it already has, according to Henning Kruse.

The chairman of EU industry think-tank TPWind and director of governmental affairs at Siemens Wind, expects turbines to continue to grow in physical size and power, but is betting that intelligent wind-sensing technology will come on strongly over the next few years.

Along with “active” wind measurement concepts such as turbine-mounted Lidar — laser-powered systems that “read” incoming wind flow — and spinner anenometers that measure directional air speeds in the flow above the nose cone, Kruse reckons “passive” technologies, such as adaptive rotor-blade trailing edges that mould themselves to the wind, will help whittle down the cost of energy.

“The 10MW, 15MW, 20MW turbines will be developed, there is no question about that, but whether these bigger machines will be manufactured in large numbers cannot be answered today because it is simply a question of cost of energy [CoE),” says Kruse.

The CoE remains too high, in his view. “This is inescapable. It has to come down to the level where wind power is comparable with the other ways we are generating energy.

“Getting there is going to be a matter of further scaling up the turbine technology we have, finding areas where we can trim costs, and developing methods of intelligent control of the turbine.”

Kruse believes the industry is moving towards a more “site-tailored” turbine, with off-the-shelf componentry including mix-and-match rotor blades and towers combined with new-age “smart” technologies to construct “more efficient, high energy-capture” machines.

“There is no point in putting the same 2MW turbine with a 100-metre-diameter rotor and a 90-metre tower on a site with low wind speed and one with high turbulence,” he says.

“On top of this, we need to look at how active and passive intelligence can be built into new designs.”

Along with sensor-driven “active” technologies, Kruse expects great strides to be taken in the area of adaptive mat-erial engineering. He points to technologies such as controllable twist blades, which dampen load vibrations using embedded multilayered piezoceramic elements, as being potential “game-changers”.

“Develop materials that have qualities that allow them to change with the changing wind speed and wind behaviour — such as blades that automatically ‘twist’ — and you immediately have a blade that is much more robust under different loads and captures more energy.”

Such technologies could reduce costs, he notes, as blades that are better at marshalling wind loads, for instance, would not only help optimise power generation, but also make it possible to “downgrade” the tower structure, making it cheaper to manufacture.

Kruse also feels there is a role to be played by mining the historical knowledge bank being amassed through the fleet of turbines already in operation around the world.

“Lidar is great. But there are other sources of information,” he says. “Computer power costs next to nothing. We know so much already about historical wind conditions in different

areas. If this database is tapped, these historical measurements could be fed into the system controller to help know what is coming next, and this will improve turbine performance and power production.”

One low-tech means of raising power output levels from wind farms in many regions is “repowering” — swapping older turbines for newer models with either higher nameplate capacity or greater efficiency.

“Historically, the best sites have also been the first sites to be developed. Why have low-capacity turbines on high-energy wind farms? Also, having high-capacity turbines on these sites would mean many old turbines that are disturbing grid integrity can be taken down and this would mean a more stable grid with increased capacity.”

Kruse predicts 3MW turbines will emerge as the industry standard for the onshore fleet “for logistical reasons” — physical limitations of fabrication, transport over existing road networks and erection at site.

“If you want to install a 20MW turbine onshore, you can, but it will never become economic. We must not forget what has gone before. We need this knowledge, but we need people to continue to think outside of the box if we are to arrive at the best outcome.

“Only this way will we achieve a ‘man on the moon’ project, like making the EU independent of fossil fuels.”