The recent Wind Power Explained conference, presented at the Design and Manufacture Expo in Chicago, presented a full day of discussions to attendees on topics from the Department of Energy, NREL, Sandia Labs, GE Energy, Northern Wind, and Clipper Windpower. Here’s a sampling:
“The DOE recognizes the challenge in making wind energy a reliable and integrated source,” said Ron L. Harris, from the agency’s Office of Energy Efficiency. Harris told how the DOE wants to ensure that the supply chain for wind technology is sufficient to increase market demand and consistent with a goal of supplying 20% of the U.S. electricity needs by 2030. “The agency also wants to maximize opportunities for domestic manufactures of wind-energy equipment by facilitating supply chain development.” In the Q&A session, Harris mentioned that developers of small wind turbines should submit ideas and products to the U.S. Army because when deployed in remote regions, they would like to take power sources other than gas-powered generators, and small turbines might work well.
Sandy Butterfield, Chief Engineer, National Wind Technology Center, discussed his experience with gearboxes. “They were a source of reliability problems and maintenance costs in early designs,” he said. “Fatigue loads were the driving loads. Since then, development of standards, such as IEC 61400-22 have helped improve their design so they are more reliable. Focus now is shifted to bearings.” Regarding turbine size, Butterfield points to the problems of shipping, such as bridges too low for large turbine blades and nacelles, that will keep land based turbines to about the maximum where they are now. “Off shore, however, the designs would have no restrictions so turbines could grow to 10 MW and larger,” he said.
Paul Veers, Technical Staff, Wind Energy Technology Department, Sandia National Labs, discussed how to get more power out of the wind. An early wind engineer Albert Betz observed that about 59% was a theoretical maximum. Recent designs have gotten bigger and taller. But a larger rotor increases in cost with the cube of the length increase, and taller towers cost go up with height to the fourth power. “Hence, the only way to win this cost battle is to build rotors that are smarter and components that are lighter,” said Veers. Then he showed several ideas for doing so.
Lawrence D. Willey, GE Infrastructure, Wind, said the U.S. is likely to see a doubling of energy needs by 2030. Good news is that wind is now cost-competitive with other fuels. “The company has developed software for engineers to guide their design work with regard to cost. The software includes influence coefficients that determine costs.
What’s more, engineers have lots of ideas, and a value analysis is one way to weigh them. “It’s a way to tell we are working on the right thing for customers and ourselves,” he says.
The beginning is the sweet spot and when to put in all the options. “You can’t start early enough when it comes to designing to cost,” he added. Even for subcomponents, this makes sense. Money spent at a project’s start is money spent wisely. When manufacturing begins, its too late for cost savings.
Taylor Robinson, VP of Global Supply Chain for Northern Power Systems, discussed how the design of company turbines makes for an efficient supply chain. “We want a supply chain close to the company and working quickly. The concepts here go back to six sigma and lean.”
“Quality will be essential from suppliers, and they must deliver on time and at the agreed cost,” he said. Components for his firm’s 100 kW turbine come from Europe and U.S. suppliers. One turbine a day is their production target. “Another goal is to get suppliers delivering more complete subsystems rather than a few components. With the right partner, it is possible to have more control over a design from a supplier than if the component were made in your own factory,” he said. Robinson added that he will work on long-term agreements with suppliers, but the arrangements have to be win-win agreements.
Derek Ptech, Director of Engineering for the 2.5 MW turbines at Clipper Windpower, said value analyses come from designing to cost. One trend in the industry is certifying the technology by third parties, such as Germanischer Lloyd.
One industry driver is that energy consumption will be up by 50% in 2020 along with a population growth of 20%. “The more steady feed-in laws in Europe have resulted in steady growth there. Likewise, because Texas has an RES, it has a greater install capacity than other states, so a national RES would be a boost to the entire industry.”
Ptech added that increased reliability is one governing ideal for the company turbines because some components have no backup. “For instance, pitch mechanisms in the hub for each blade work independent of each other and so have batteries to run them in case conditions take the turbine off grid. Dramatic events define design conditions,” he said. Another example is that the Clipper has four generators so that one, two, or three of them can be removed and the turbine still produces power.
Filed Under: Components, Policy, Turbines