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Resisting the Allure of Small Wind Turbines

Backyard wind turbines are less appropriate than they seem

Posted on Nov 20 2009 by Martin Holladay, GBA Advisor

Wind turbines have a hypnotic allure. The Siren call of carbon-neutral electricity has led many environmentalists to dream of owning a backyard wind turbine.

Unfortunately, small wind turbines, unlike utility-scale wind turbines, are rarely cost-effective, even when installed at a good site. Installed at an average site, a wind turbine is little more than an expensive toy.

Most renewable energy consultants can share tales of small wind turbines that have disappointed their owners due to low energy production or frequent maintenance problems. That’s why it’s so important for wind-besotted greenies to do their homework before going turbine shopping.

Wind-generated electricity isn’t cheap
Even homeowners blessed with a fairly good wind site pay a steep price for wind-generated electricity.

One of only a handful of successful net-zero-energy homes in the U.S. is one owned by David Pill and Hillary Maharam of Charlotte, Vermont. Although most descriptions of their prize-winning house note that their 10-kW Bergey wind turbine generated more electricity during a 12-month period than the family used, few noted that their electricity is very expensive.

During its first year of operation, their wind turbine produced 6,286 kWh of electricity — worth about $627 at the current retail rate of $0.10 per kWh. That means that the $40,500 wind turbine will have a simple payback period of about 64 years. Unfortunately, the turbine is unlikely to last that long.

The same amount of electricity could have been generated by a 6-kW PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. system, which the Pills could have installed for $30,000. Since their home was built, the price of PV has dropped; in 2013, a 6-kW system could be installed for $24,000 or less. (For a somewhat different payback analysis, see David Pill's comment of 09/12/2011, posted in the comment section below this article.)

“In a good site, wind will be marginally cheaper than PV,” said Andy Shapiro, the Vermont energy expert who acted as a consultant on the Pill home. “But a spinning machine will have more maintenance over time.”

Another energy consultant with wind experience is Rob Meyers, energy efficiency and renewable energy integrator at South Mountain Company in Chilmark, Massachusetts. Meyers regularly encounters customers who are eager to install a wind turbine. “We always get these people to back up and agree to do efficiency measures first,” said Meyers. “Then we try to talk them out of installing a wind system. Our company has established an internal moratorium on residential wind installations. We feel that wind turbine manufacturers are undercapitalized and unable to adequately address maintenance issues. We feel that small residential wind is not really a viable solution.”

Arguments for going slow
There are four main reasons to hesitate before purchasing a wind turbine:

  • Electricity generated by a small wind turbine is significantly more expensive than grid power.
  • Many communities require landowners to jump through a series of regulatory hoops to obtain a permit for a tall tower. Even if a tower permit is approved, lingering resentments arising from testimony provided during the permitting process can sour relations with a turbine owner’s neighbors.
  • A wind turbine is a mechanical device with many moving parts, and turbines are deliberately exposed to a site’s worst weather. To perform regular maintenance procedures, either someone will need to climb the turbine tower, or the entire tower will need to be lowered to the ground. Each maintenance event is a significant expense.
  • Many studies have shown that most performance predictions for small wind turbines are exaggerated. Inaccurate forecasts are due to a variety of factors, including optimistic estimates of average wind speeds, inaccurate performance data from turbine manufacturers, and in some cases deliberate deception by turbine dealers.

One recent study by Shawn Shaw of the CADMUS Group, “Status Report on Small Wind Energy Projects,” examined the performance of 19 small (under 10-kW) wind turbines. The study found that on average, the wind turbines produced only 27% of the annual electricity production estimated by the wind turbine installers.

Shawn concluded, “Though the overall performance of the small wind systems installed in Massachusetts is lackluster thus far, the technology appears to be viable but highly subject to variables which are difficult to quantify (e.g. turbulence, wind speed, etc.). … In order to realize cost effectiveness on par with, or better than, PV systems, more action will be needed to educate installers and to weed out systems that will not meet performance expectations.”

Anyone thinking of installing a wind turbine should heed the advice offered in an unsigned article on the Web site of Home Power magazine: “Small-scale wind energy is not for the half-hearted, uninvolved, or uncommitted, and probably not for folks who never change the oil in their vehicles (or are willing to spend the bucks to hire someone to do the tower work). The North American landscape is littered with failed installations: Designs not fully thought-out or tested, machines bought because they were cheap, and installations that required more time and money for repairs than they ever yielded in electricity generated. Many of the failures were the result of wishful thinking and too little research.”

Whatever you do, resist the temptation to install a small wind turbine on a building:

  • When wind hits a building, turbulence is created; such turbulence greatly interferes with power production.
  • Building-mounted turbines can cause irritating vibration and noise.
  • Studies have confirmed that most building-mounted turbines have produced far less electricity than predicted.

To learn more about the pros and cons of building-mounted turbines, see “The Folly of Building-Integrated Wind,” Environmental Building News, May 2009, and Mick Sagrillo's An open letter to inventors of vertical axis wind turbines and rooftop wind 'technology breakthroughs.’

The economics differ for off-grid homeowners
Some of the caveats listed above don’t apply to off-grid homeowners. Since those who live off the grid are accustomed to very expensive electricity, they are more likely than grid-connected users to put up with the high cost and maintenance burdens of a small wind turbine.

Off-grid homeowners lack access to the grid’s “infinite battery,” so it may make sense for them to install a PV array to cover most of their summer loads and a wind turbine to pick up the slack during the dark but windy winter months.

Last week’s blog: “Ten Ways to Improve a New Home.”


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Image Credits:

  1. Abundant Renewable Energy

1.
Fri, 11/20/2009 - 07:58

Integration
by Jamie Wolf

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Thanks for the focus of this post (interesting counterpoint to the "sustainable McMansion" piece by Richard Deffendorf). It goes hand and hand with a comment made in your EBN feature on solar by Steven Strong that, despite its unreasonable expense, architects (and their clients) love building integrated photovoltaics because you can see them (unlike a better envelope - note to self: work on artful expression of wall thickness).

It doesn't help that turbines are the most evocative icon of renewable energy - if there were as many operating (effectively) as there are on "green" web pages and featured in magazine articles and oil co. ads we'd be in good shape! People like shorthand and easy answers and wind turbines in backyards fit that bill. Let's hope your insight is observed and communicated. And where is the "eagle" of efficiency - we need an icon!

Tucked within your post is a really significant job description. Rob Meyers is the "energy efficiency and renewable energy integrator" at South Mountain Company. Now we're talking! Until we move beyond the fractured single line disciplines of roofing, siding, windows, insulation, HVAC, solar, wind, ground source, on demand DHW, and the third party auditor with no direct role in integrating all of the above (with hands tied by stimulus programs), we're going to have a hard time getting this to work (as in work together as a system, which is the point). Someone needs to play that role and be accountable to a client in assuring performance, while providing the kind of guidance that Rob offers and you are encouraging here. We need "integrators".


2.
Fri, 11/20/2009 - 11:11

Wind Turbines as green dogma
by Andrew Henry

Helpful? -1

Hi Martin,

I was recently thinking about the issues you bring up in this post with respect to one homeowner in my area who dogmatically pursued approval for a wind turbine installation in his backyard. Unsurprisingly, his pursuit of approval against the wishes of his neighbours has probably created a great deal of resentment.

The sad thing, for anyone who knows where the 'low hanging' green fruit lies, is that his home was a typical suburban home, built to the minimum standard (the code). The money he would have put into the turbine could have been put into improving the energy efficiency of his home, and would have had a much better (profoundly) cost/benefit ratio than the turbine. And he wouldn't have pissed off his neighbours!

The various levels of government, business and the consumer who want to be green seem to spend far too much time advocating/demanding for glamorous renewable energy and very little time cheer-leading the much more cost-effective load reduction and end-use energy efficiency approaches. It's understandable, load reduction and end-use energy efficiency is pretty homely looking compared with glamourous renewable energy. Anyone know how to make load reduction and end-use energy efficiency 'hot'?

Cheers,

Andrew


3.
Sat, 11/21/2009 - 17:56

Nothing new here
by Ryan

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Being one of the largest manufacturers of small-wind systems, the UK has conducted many studies on the performance of small-wind in residential application (see Warwick Wind Trials for example). Unfortunately, it's true; even with vast "wind resources" these reports note significantly lower performance than what wind energy yield tools predict. The problem is that wind is just inherently hard to predict or model - microclimate wind conditions (ie. affects of trees, buildings) can be completely different in two close locations, although they would share the same average wind speed which is used in predictions.

Having said that, all renewable energy products take time to reach economies of scale, learning curve improvements, so who knows where the industry could be in 10 or more years...


4.
Tue, 11/24/2009 - 08:24

Integrators , Great concept that is sorely needed!
by Edward Palma

Helpful? 1

Great point from Jamie. More businesses whether they be small or large should incorporate design and building professionals as "energy efficiency and renewable technology integrators" into there staff. This is especially true for businesses that deal with residential clients. The green building movement is attracting many consumers who are not well educated on energy efficiency, energy load reduction, and the principles that can green an existing home prior to spending vast amounts of money on glitzy energy systems. Their decision to promote a green living environment for themselves, leaves much opportunity for an experienced professional to educate them on how to integrate different aspects of sustainable life and renewable energy systems into their homes. With the vast number of existing houses that need to be upgraded, and the economy forcing people to stay and renovate their homes "integrators" become sustainable living and green building "counselors". People need someone to essentially hold their hands and walk them through the design and construction process of upgrading their homes and lives. Educating the people spreads to others, and each client provides the professional with a personal experience that can be related to their next client. It is a symbiotic relationship that benefits everyone. Bravo to South Mountain Company for this innovative concept! E. J. Palma , Branford, Connecticut


5.
Sat, 11/28/2009 - 13:01

turbines
by Tom williams

Helpful? 1

if you feel that way why not check out a reputable dealer. The wind generators wind turbines at hurricane have done a great job for me actually lowering my power bill by half


6.
Sat, 11/28/2009 - 14:57

Reputable dealers
by Martin Holladay, GBA Advisor

Helpful? 1

Tom,
I have already checked out reputable dealers of wind turbines; however, checking out reputable dealers has not altered my conclusions.

I respect these reputable dealers, by the way, since wind turbines are useful equipment for off-grid homeowners. Many wind-turbine dealers do a great job serving the off-grid market.


7.
Sat, 05/08/2010 - 07:56

wind
by Anonymous

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Sounds like Martin's working for the PV cell companies.


8.
Sat, 05/08/2010 - 08:09

What causes such cynicism?
by Martin Holladay, GBA Advisor

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Anonymous,
It sounds as if the only possible explanation that someone might have a different perception than you do is that the opinion is being expressed by someone on the payroll of a corporation.

I think your level of cynicism is unnecessarily high. I can assure you that I have no relationship with any PV companies, and have often written blogs advising against investments in PV.


9.
Mon, 09/12/2011 - 09:22

Clarification
by David Pill

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Hi Martin-
Just happened to come across this article. I would have commented sooner. I would like to make some clarifications. Not that it matters to your point but our electricity costs $0 .14/kWh.
At the time PV was about 8 - 10 per watt. Our modeling showed that we would use approximately 8000 to 9000 kWh per yr so we would need around an 8kW to 9kW system. Using $8 per watt, the cost would have been between 64K and 72K. From wind maps it appeared that we would produce around 8000 kWh with the turbine at a cost of $40,500 so it made sense at the time. Also, you probably left out the rebates for a reason but the final cost was 28K, and with today's 30% tax credit (not available at the time) the final cost would be 16K. Now in 2011 with PV costing in the sub $5 per watt range, it would have been an obvious choice. While we definitely overpaid for our electricity in 2007 dollars by purchasing the wind turbine, by doing that we were able to pre pay all of our energy costs, including heat and HW, by wrapping that cost into our mortgage to be completely independent of any electricity or fuel price increases for at least the next 20 years.


10.
Mon, 09/12/2011 - 09:46

Edited Mon, 09/12/2011 - 09:57.

Response to David Pill
by Martin Holladay, GBA Advisor

Helpful? 0

David,
Thanks for the clarifications. They are much appreciated.

I have edited the blog to include a reference to your comment.


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