GE is Working on
In a move that it believes could put wind energy on an equal economic footing with conventional fossil fuels, GE, along with Virginia Polytechnic Institute & State University (Virginia Tech), and the National Renewable Energy Laboratory (NREL), is to begin work on a project that it says could fundamentally change the way wind blades are designed, manufactured and installed.
The underlying economic logic suggests that with most of the cost of electricity for wind tied up in the initial capital investments made in the wind turbines themselves, new technology advancements that reduce these costs could substantially lower the overall cost of wind energy.
What GE intends is to create a new kind of blade, one that can be made 130 m or more in length, from a skin-and-frame design similar in principle to early aircraft wings. "GE is weaving an advanced wind blade that could be the fabric of our clean energy future," said Wendy Lin, a GE principal engineer, and leader in the US Department of Energy's Advanced Research Projects Agency (ARPA-E) project. "The fabric we're developing will be tough, flexible, and easier to assemble and maintain. It represents a clear path to making wind even more cost competitive with fossil fuels."
According to GE, this new blade design could reduce blade costs 25%-40%, making wind energy as economical as fossil fuels without government subsidies.
GE's research will focus on the use of architectural fabrics, which would be wrapped around a metal spaceframe, resembling a fishbone. Fabric would be tensioned around ribs which run the length of the blade and specially designed to meet the demands of wind blade operations. Conventional wind blades are constructed from fibreglass, which is heavier and more labour and time-intensive to manufacture.
Such an advance in blade technology would help spur the development of larger, lighter turbines that can capture more wind at lower wind speeds. Current technology doesn't easily allow for construction of turbines that have rotor diameters exceeding 120 m because of design, manufacturing, assembly, and transportation constraints. Wider, longer wind blades are tougher to move and manoeuvre, and moulds which form the clamshell fiberglass structure cost millions of dollars to acquire. A fabric-based technology would all but eliminate these barriers. Components could be built and assembled on site, meaning design engineers no longer have to concern themselves with manufacturing and transportation limitations.
It is estimated that to achieve the national goal of 20% wind power in the U.S., wind blades would need to grow by 50% -- a figure that would be virtually impossible to realise within the size constraints imposed by current technology. Lighter fabric blades could make this goal attainable.
"Developing larger wind blades is the key to expanding wind energy into areas we wouldn't think of today as suitable for harvesting wind power. Tapping into moderate wind speed markets, in places like the Midwest, will only help grow the industry in the years to come," Lin commented.
The use of fabrics to reduce weight and provide a cost-effective cover dates back to the World War I era, when it was used on aircraft. Over the years fabric has proved to be rugged and reliable and GE has already begun using this spaceframe/tension fabric design in the construction of wind towers for better aesthetics, cost, and protection.
The $5.6M ARPA-E project will run for three years. GE's blade architecture will be built with the aim of achieving a 20 year life with no regular maintenance required for tensioning the fabric.
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