January 16, 2008
The News-Review
Michelle Myers

Building Your Own Wind Turbine

Farmers get a lesson in how it can be done.

Here's a challenge. Build your own wind turbine and kiss goodbye to LIPA bills.

That was one of the offerings at the recent 27th annual Long Island Agricultural Forum at Suffolk Community College.

The cheerful challenger was Roy Rakobitsch, a wind design engineer and consultant with Go Solar Inc. Under the disconcerting gaze of a prehistoric-looking puffer fish in a marine studies classroom, Mr. Rakobitsch started out with what he calls his standard safety disclaimer -- wind is pretty dangerous to work with. So apparently are some of the components of a turbine. For example, the magnetic parts will damage computers, credit cards and pacemakers (not to mention human bones if the magnets snap together unexpectedly.)

Apparently undaunted by the prospect of taking their lives into their own hands, the enthusiastic members of the audience were treated to an overview of the basic principles of a small wind turbine. Why wind? Wind turbines provide the highest power density for the dollar, as there is no fuel cost, the system can be tied to the grid and can be custom designed by the user. And on Long Island there's almost always some wind, where there may not be enough sunlight hours every day to make a solar application as cost effective.

Mr. Rakobitsch reassured the crowd that the best DIYers are ranchers and farmers and that the turbine construction process is easy, cheap and -- that word again -- dangerous. One basic question to ask before commencing a project is to what use the power will be put. In that regard, Mr. Rakobitsch feels it's not inevitable that a renewable energy system be designed to charge a battery bank. The energy could be used to heat coils in your house's heating system instead, or it could even be fed back into the grid. Another threshold issue is how much power is needed once you have determined your windmill's purpose.

And so to the heart of the turbine, the homemade axial flux alternator, the most expensive parts of which are those pesky magnets. The axial flux design alternator is superior to a radial design as it works efficiently with low wind speeds, has a long service life and normally only requires routine maintenance. The idea here is to maximize energy production in low winds as high winds easily cause damage to the equipment.

Every windmill requires blades and Mr. Rakobitsch urged matching the size of the blades to the alternator's operating range. (If the blades are too small, there will be insufficient energy to start the alternator in low wind. If the blades are too big, they will spin too fast.) Almost any kind of relatively lightweight wood is appropriate to use for the blades, although cedar is probably the most common.

In spite of Mr. Rakobitsch's reassurances, the whole process was beginning to sound very technical. One audience member asked how many hours it would take to build a turbine, but Mr. Rakobitsch couldn't be pinned down. "It becomes an obsession," he said. His class handout suggests it will take a while, given the numbers of drawings needed, the cutting of the wood, the holes to be drilled in steel, the welding, epoxy mixing, wire winding and "scratching your head in puzzlement quite a lot, too."

Keeping their credit cards well away from the source of their destruction, the audience gathered around to examine the axial alternator, and most, like Nabeel Massoud of Paumanok Vineyards and Water Mill farmer Mark Corwith, who both peppered Mr. Rakobitsch with questions, appeared to be interested in agricultural applications.

Not all the attendees were looking at wind turbines from the agricultural point of view, though. Some, like Tamson Yeh, were interested in domestic applications and were disappointed to learn that building codes in our area almost definitely would not permit a wind turbine on a small lot. "I'm a turf grass and land management specialist," she said. "But I'm here really to familiarize myself with something that's going to become critically important environmentally to our children. And yes, it's a shame there's no real way for homeowners to make use of this unless they have a lot of land." Mr. Rakobitsch confirmed that rooftop wind turbines, which have generated a lot of press recently, are really not efficient enough to produce a substantial amount of energy and that to be truly effective a turbine must be on a tall tower. (Air turbulence caused by neighboring buildings and obstructions such as trees can radically affect performance.)

Anthony Wolbert, a member of the Southold Town renewable energy committee, also came to the seminar to learn about the possibilities of wind turbines for domestic use. "We hope we can eventually modify the town code to allow people to erect their own wind turbines," he said. "Windmills have been around a long time but the light was just turned on, so to speak, in terms of using them in this way."