March 11, 2012 – Vol.16 No.52
by Bruce Mulliken, Green Energy News
This you surely know: Some people don’t like wind energy. It’s true. They have their complaints and in all fairness should be heard. Wind opponents say, “Wind turbines can be a blight on the landscape.” “Turbines are noisy.” “They kill birds and bats.” “Wind energy is too expensive.””What good is wind energy if power is only intermittent?” All legitimate concerns.
But what wind opponents should make note of is that the wind industry acknowledges these concerns and continues in its attempts to rectify them. Like any other power generating technology, change, cures for problems, and the adoption of new technologies, don’t happen overnight. If one were to hop in a time machine and travel forward 30 or 40 years, wind energy would look quite different than it does today.
For example, deep water, floating offshore wind is just in the experimental stage. It came about in answer to nearly all the above concerns. Turbines aren’t a blight on the landscape if they’re over the horizon, out of sight from land: out of sight, out of mind. Turbines that can’t be seen, probably can’t be heard either. Few birds travel far from shore. (Bats don’t at all, as far as I know.) Stronger, more steady wind translates into higher output, more capacity utilization and lower costs per kilowatt hour.
I would expect that decades from now much of the world’s wind capacity will be far off shore or in the remotest, uninhabited regions of the planet.
Turbines of the future, too, might also be much different as new technologies continue to be developed.
One company for example, Boulder Wind Power (BMP), is developing a new direct drive turbine that could deliver clean power that’s 30 percent less costly than other geared and direct drive designs.
At the heart of the BWP design is the company’s proprietary axial gap, air core, permanent magnet direct drive generator. In its website the company says, “The BWP technology can produce the same torque with less than half the mass (Nm/kg) of comparably rated iron-core direct drive generators. Our proprietary air-core stator contains no ferromagnetic material, therefore eliminating all magnetic attraction between the rotor and the stator ... this feature enables lightweight, flexible stator and rotor support structures".
Not only is the Boulder Wind Power generator design lighter and more powerful, the machines should be less expensive to build: The generators can be built on automated production lines cutting labor costs associated with conventional wind turbine gensets.
Again, from the company website:
“Multi-megawatt generators are manufactured using low-volume production methods. These methods are dependent on highly skilled labor and introduce a concern that build quality will depend on the skill of the craftsperson performing the task. The BWP stator, by contrast, is manufactured using mature and repeatable printed circuit board (PCB) operations. Perfected by the proliferation of computer technology, PCB manufacturing is ubiquitous, robust and cost effective. Our engineers, using proprietary design tools developed by BWP, prescribe the circuit to be etched on the PCB. This formula is electronically transferred to the PCB manufacturer and the PCBs are etched or “printed,” stacked, pressed, drilled, and plated. This automated manufacturing simplicity is unique to BWP for wind turbine applications and it leverages the low cost, high quality, globally installed PCB production base.
“BWP’s stator winding insulation is applied to the conductors as an integral part of the automated stator manufacturing process developed for the PCB industry over the last 50 plus years. As such it is subject to very effective manufacturing process controls. This eliminates the common defects associated with conventional motor and generator manufacturing. The BWP insulation and conductor support system is uniform over the entire conductor surface - the end turn areas are encapsulated and supported in the exact same manner as the working area conductors. This is vastly superior to conventional construction, in which the end turns are cantilevered and unsupported.”
Without investing millions in a megawatt scale, utility grade wind turbine, you can get a taste of the Boulder genset design by purchasing a weed whacker. (Yes, a lawn care device.) A design similar to the wind turbine generator is used for the electric motor that drives the new battery powered grass and weed trimmer from CORE Outdoor Power.
Another wind turbine design that shows promise is the WindWheel(tm) from Chance Wind of Wichita, Kansas. The WindWheel is something like a bicycle rim with five blades as well as cables, like spokes, that connect the rim of the “wheel” to the hub. As the WindWheel turns in a breeze the rim rides on a pair of rollers, like tires, that are connected to permanent magnet generators to generate electricity. (You can click on the company website for a more detailed description and a video.)
Right now the company is offering only a 100 kilowatt version, suitable for remote or distributed power, but the design looks scalable to larger capacities.
The addition of a “ring” to connect the blade tips is not new: Many small wind turbines utilize rings. What is new is using the ring as part of the electric generation system as opposed to having the generator in the hub or nacelle.
The ring may also be a way to put an end to bird strikes. Apparently, if birds see turbines as solid objects they’ll steer clear. (Birds don’t see large turbines as solid because the blades move so slowly. As they attempt to pass through the air space between blades they get hit.) The ring, as well as the the cables, might make the WindWheel appear solid. The company doesn’t make this claim, but it certainly could be tested.
As wind becomes a mainstream source of energy, new generations of designers and engineers, full of ideas of their own, are just now students in their teens and learning about wind turbines.
In Maine, dozens of students are participating in the Maine Wind Blade Challenge, a competition hosted by a partnership of the Maine Composites Alliance, the Maine Wind Industry Initiative (MWII) and the University of Maine.
“Wind blade design is really just a fantastic vehicle for the exploration of many STEM (Science, Technology, Engineering and Math) related principles.” according to Paul Williamson of the MWII. “This activity really allows the students to use those principles to use their own hands and creativity to produce a working model. It also helps them to understand broader issues related to wind energy. ”
On April 27 King Middle School, in Portland will be one of the first two middle schools to compete in the event that until now has only involved high school students. Old Orchard will be the other middle school competing. The wind blades designed for that event will be fully developed advanced composite structures incorporating the principles learned at King Middle School.
Boulder Wind Power
CORE Outdoor Power
Maine Wind Industry Initiative
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