In providing renewable energy solutions to homeowners I am frequently asked "what about wind?" For some reason people are curious and attracted to the idea of wind machines creating energy. Perhaps people like the sight of a wind mill. It is active; one can see it in motion working to produce energy. Often wind machines conjure up images of windmills pumping water . . . maybe there is a romantic element to the attraction of wind machines - a getting back to the land sort of thing?
My standard answer to the question is that wind is good but solar electric is better – at least for the large majority of homeowners. Solar electric has no moving parts. It requires little or no maintenance, it’s quiet, robust and fairly efficient. Wind on the other hand has not only moving parts but parts that move at very high speeds and are susceptible to vibrations. Wind machines require maintenance, repair and parts replacement. Don’t get me wrong, wind has its place.
Personally I do not think residential roof tops are the place (there are exceptions). Roof top machines in residential neighborhoods face the challenge of neighbors not liking the motion, flickering light, the sound etc. In addition local jurisdictions may pose a challenge with permitting. There have been consistent claims over time by firms stating they have small rooftop machines that will generate X# of kilowatts with low wind speeds etc. etc.
Far too often these claims fall short of reasonable expectations. Fairly recently the state of California suspended rebates on a machine that was not performing as claimed. Now in fairness to the manufacturer it could have been misinterpretation or miscommunication of the engineering data/production claims, or maybe an honest mistake…or not. Nonetheless it is another concrete example of residential roof top wind machines not sizing up to solar electric.
For your average land owner, in general terms, you need acreage and high sustained wind speeds (approx. 12-15 mph+), day in and day out to justify a wind machine. I am not referring to a small rooftop machine but rather a larger machine sitting atop a tall tower. These machines have their place in farms, wineries, ranchettes, etc. Wind machines need a significant distance of open space from buildings, trees, etc. that will not disrupt the wind flow. One might make a comparison of buildings and trees impacting wind as they impact sun or shade on solar electric systems.
As noted in a prior column, with solar hot water vs. solar electric- wind machines can be a good fit in off grid applications. Having a fairly small machine on site that can trickle charge batteries might be a good idea. Unlike solar electric, wind can produce in low light cloudy conditions and at night.
Commercial or large scale utility wind farms are a different story — the kind of huge towering and vast windmill farms or fields that you see in California’s coastal mountain passes that our national highways run thru. These wind machines are truly on a very different scale physically and economically. On the opposite end of the spectrum of the large utility machines are small residential roof top machines that are still finding their place in a broad market of competitive renewable energy options.
