Small scale wind power

One of the sentiments I hear a lot from various people I speak to about energy and environmental issues is a desire to put a wind turbine on their home. I think this is a combination of factors at work, including wind’s (deserved) reputation for being a very clean, renewable energy source, and people wanting to avoid paying their monthly electricity bill, or at least reduce it greatly.[1]

This undercurrent came to mind when I read Small Wind: Southwest Windpower Gets Funding for Home Turbines:

For all the talk of a new “Apollo Program” or “Manhattan Project” to meet America’s energy needs, is the answer to think small?

Plenty of big-name energy investors think so, pouring fresh funds into a company that makes tiny wind turbines for residential use. The idea is to bypass the traditional model of big, centralized power generation stations—whose need for equally large power transmission systems are creating such an expensive headache–to provide electricity on a home-by-home basis.

Investors including GE Energy Financial Services, Altira, Rockport Capital Partners, NGP Energy Technology Partners, and Chevron’s CTTV Investments participated in a new $10 million funding round for Southwest Windpower, based in Flagstaff, Ariz.

In the context of hundreds of billions of dollars of federal stimulus spending, the amount is miniscule. But the idea is big. Southwest Windpower’s Skystream residential turbine can meet more than half a typical home’s energy needs, the company says—and more cheaply than by buying power from the grid. On windy days, residential systems can sell power back to the electric grid, helping shave power bills further and giving power companies access to clean energy.

I’ve never been convinced that small scale wind power would ever be more than “a niche of a niche” in terms of how much power it generated or how much atmospheric CO2 it helped us avoid creating. Still, thanks to the links in the above article, I did a little digging around, and found some good news and some not so good news for those lusting after their very own wind turbine.

First, let me start with the stimulus overview [PDF] provided by Southwest Windpower. In that document and the related spec sheet [PDF], they talk about their Skystream turbine, which has a service life of 20 years and a rated generating capacity of 2.4 kW. See the spec sheet for graphs that map wind speed to both power and monthly energy generation, and the wind resource maps linked from their page Is wind right for me?.

So, is wind right for me?[2]

I checked the wind map for NY State [PDF] to see what they had to say about Rochester. As best I can tell from the odd way the map is colored, they have Rochester in a light green area, which indicates an average wind speed of 11.2 to 12.3 mph, but at a height of 30 meters, the lowest height for which NY data is available. The price quoted for the Skystream model includes a 33 foot tower, quite a bit short of 30 meters, and I suspect it makes a big difference in ow much wind I could catch. In Rochester, we get some incredibly windy days, but we also get stretches of days (like right now) when there’s not enough wind in my neighborhood to muss your hair, let alone spin a turbine. I’m skeptical of that 11.2 to 12.3 mph number, but I’ll use it anyway.

In the stimulus overview [PDF], Southwest Windpower says that the Skystream costs $14,000, with a federal incentive of $4,200, leaving the pre-state incentive cost at $9,800. Eyeballing their cost vs. wind speed graph in that same document, it looks like 12.3 mph average winds over 20 years results in an electricity cost of about 12.5 cents/kWh. This looks like a very reasonable estimate. The spec sheet says that at 12.3 mph the Skystream produces 400 kWh/month. That’s a total of 96,000 kWh/month, or 10.2 cents/kWh, without adding anything for maintenance or interest payments. I would definitely call their estimate accurate, at least as much as any estimate based on averages can be, even though they seem to be making a generous assumption about the needed tower height. Speaking as a consumer, I would definitely consider installing a turbine like this, assuming I had the land, even though the electricity cost would be slightly higher than I pay now for grid electrons.

But wait–there’s more, as in more incentives. The NY State incentives are, to no one’s surprise, vastly more complex than the federal incentives. (My fellow New Yorkers who have filed state income tax forms will know instinctively what I’m talking about.)

The NY State incentives include model-specific values, plus a set of multipliers(!?) to raise or lower the incentive, depending on who is using the turbine. For the Skystream the residential incentive is a whopping $7,200. This drops the cost of the Skystream to $2,600, while the cost of electricity plummets to a mere 2.7 cents/kWh.

It seems that financially small scale wind turbines are a good deal for residential use, provided they’re heavily subsidized. With no incentives at all, the cost of electricity is about 14.6 cents/kWh, at least 3 cents/kWh above what my wife and I pay for 100% green electricity (which comes from wind and small hydro).

So, what to make of all this?

• The economics are more attractive than I thought. I doubt that small scale wind turbines will be broadly economically compelling on their own, unless the price of grid electricity rises sharply in many areas. But for many consumers just the federal incentives alone are enough to make this kind of investment attractive.[3]
• Small scale wind power will continue to be severely limited by the proximity of neighbors. Currently, the spacing requirements are such that only people living in rural or semi-rural areas can install an appropriately sized tower. There will be more creative wind power solutions, such as smaller generators that can be mounted on a roof, as well as turbines optimized for use on office and apartment buildings, schools, etc. For most home owners, solar panels will make much more sense, especially as their price continues to drop.
• My guess is that a residential wind turbine would make little sense without a net metering system in place, which (of course) varies greatly from state to state in the US. I would expect that without net metering some of the gusty winds in Rochester, often at night, would be totally wasted. The turbine would be produce more electricity than we consumed, and we’d get no economic benefit from it.
• The incentive programs (yeah, I’m looking at you, Albany) need to be much simpler. I would prefer to see the incentives based on the average wind speed at the installation site and the size of the wind turbine–in other words, tied to the amount of electricity you actually generate. Even better yet would be to ditch the up-front incentives and estimation process entirely and use a feed-in tariff, which would give consumers a strong incentive to conserve electricity and maximize their net metering receipts, since those would be at a higher cost per kWh than the normal grid rate.
• If we had the space, I would be working overtime to convince my wife that we simply had to have one of turbines, if only for the cool factor.

[1] This is part of the general American desire to “stick it to the man”, whether said man is an oil company, an electricity or natural gas supplier, OPEC, or whomever.

[2] My house isn’t a serious candidate for a this type of wind turbine, as a 33 foot or 30 meter would be far too close to my neighbors, even if I could get the local permits to erect the tower. I will assume for the rest of this post that I do have the proper buffer between properties, which Southwest Windpower says usually requires a one-acre plot of land.

[3] I realize that the cost of electricity is about to start changing dramatically in at least some parts of the US. Putting a price on CO2 emissions means higher prices, likely by a few cents/kWh, for people who primarily get their electricity from coal plants. And by “economically compelling” I mean a price that’s attractive enough to get the attention of and entice the non-energy geeks in the population, you know, the other 99% of consumers.