Research needed before installing wind generators

By Tom Gocze, BDN Staff
Posted July 10, 2009, at 6:41 p.m.

Last weekend we decided to get away from the tourists on the coast, so we headed inland. I thought it would be interesting to go look at the wind generators in the town of Freedom. It was only a short ride from where we were and the ride on the back roads was delightfully free from cars from out of state. In fact, there were no cars at all.

As we got onto Route 137, I spotted the three wind generators off in the distance. We just kept going in what seemed like the right direction and before long we were within a couple hundred yards of the wind units. They are impressive.

I wonder about the aversion to them, given the fact that what went up on these ridge tops can always be removed. They are interesting to see.

I like the fact that they are a fast-track technology and they do (I assume) yield the property owners and local towns some revenue. They are certainly not without controversy, but it seems that nothing is without controversy these days.

If you get a chance, take a drive sometime and get a look at them. I think they are more visible from a distance than they are close-up. And I would not want to suggest anyone go trespassing on private property to get close.

I believe we can see that when well-sited, these generators can produce a reasonable amount of energy annually.

So let’s consider another wind technology: building integrated wind generators. These are small wind units that are mounted on the top or edge of a tall building in a city. The inventors claim that these are the next big thing. These devices are the darlings of the green TV programs and they get a lot of media coverage.

That is the problem — so much of the national media, TV in particular, does not get into the actual numbers. After all, many TV people are not hard-nosed investigators. If they are, they are usually looking for adulterers, murderers or crooked politicians. Any combination of those is like hitting the TV producer’s lottery.

So “green” inventions, such as rooftop windmills for big-city applications, are a great visual, and the inventor (or manufacturer) is taken at his word, which is usually laced with a lot of superlatives about their technology and very little documentation.

The good news is that these TV notices come and go (except for reruns). One hopes that someone who understands proper testing and engineering takes the time to test these things and report on them.

Maybe that is my job today, since there are no murders happening.

I am not doing the testing, just reporting what I have found.

Research is showing that rooftop wind generators perform rather poorly. There is a lot of turbulence that affects their operation. They are also usually rather small. Wind technology works best with really big generators. Big wind generators harvest a lot of wind energy because they can intercept a large area of wind. The larger the area the blades sweep, the more energy generated. This affords large machines a cost-benefit ratio that is unattainable from small installations.

Small rooftop units cannot compete nearly as well in an urban environment. The small area of wind that they intercept is almost inconsequential given the cost of installation. I hate to think about the possibility of something mechanical on the roof of a high-rise breaking off in a high wind and plummeting to the ground below. Talk about a bad day!

Two recent reports (one in the United Kingdom and one in the U.S.) indicate that small wind turbines far underperformed manufacturers’ specifications.

It seems that if people in a city want to do the “green” thing, they should consider rooftop gardens, photovoltaics or solar thermal and leave the wind installations to areas where the resource and scale can truly accomplish something helpful to society (and avoid killing or maiming random people with falling hardware!).

I am in no way trying to dissuade our neighbors in rural New England from thinking about wind generators. Just do the math, and ask for documentation of performance — better yet, talk to someone who has a system to find out how well it performs.

I hope we all can think rationally about the true costs of our investment in renewable energy and spend wisely.

Questions for Tom Gocze may be mailed to The Home Page, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. A library of reference material and a home-project blog are at www.bangordailynews.com/thehomepage.html.

http://bangordailynews.com/2009/07/10/living/research-needed-before-installing-wind-generators/ printed on August 27, 2014