Wind in the silos


On-farm wind power: Part III

By Dan Sullivan
Originally posted June 10, 2004

Wind turbines typically roost atop the tallest towers practical for one’s budget and site specifically because higher up is where the most wind is. That’s also where another naturally occurring phenomenon presents itself in all its spectacular fury—lightning.

But the popular myth that lightning is always attracted to the tallest metal object is just that—a myth. So said wind power expert Mick Sagrillo, who guided a day-long Wind Energy on the Farm course last February as part of the Upper Midwest Organic Farming Conference’s Organic University.

Lightning is formed by static electricity on a grand scale, Sagrillo said, caused when two dissimilar materials—in this case the atmosphere and the earth—rub over each other. Just like you receive a shock when you touch a doorknob after shuffling across the carpet in your socks, he said, lightning operates under the same principal, that is, equalizing the buildup of a static charge.

Of course trees, and sometimes windmills, do get in the way.

“[A windmill tower] is sitting on concrete and that’s somewhat of an insulator,” Sagrillo said. But certain precautions can minimize your chances of having your wind energy system damaged by lightning, Sagrillo said, including grounding each leg of the tower, as well as the base, “with an 8-foot ground rod as deep as you can get it.”

When lightning does cause damage to a wind machine, Sagrillo said, it typically gains access from the utility side. “Ninety eight percent of the time, the lightning came in on the utility grid [AC] side; it did not come in on the generator side.” For that 98 percent, Sagrillo said, surge suppressors are beneficial. While surge suppressors on the AC side—and lightning arrestors, ground rods and conductor cables on the tower side—do afford some protection against lightning damage, they provide no guarantees, particularly against a powerful direct hit. That’s were adequate insurance comes in.

Detractors of wind power (including some utility lobbyists) point to the potential eyesore that a tower and large windmill can create, safety hazards that can result from a loose blade or accumulated ice that has been shed, potential interference with communication devices, stray voltage (small amounts of electricity that can leak from power lines and on-farm equipment that may adversely affect livestock), and perceived danger to wildlife (particularly birds).

But when you consider alternatives for producing electricity—such as coal plants that destroy the ozone layer and poison waterways and their inhabitants, and nuclear reactors with the potential to core the earth like an apple—you realize that such hazards present a tradeoff. (Many of these concerns are addressed later in this piece.)

“Cats kill 37 million birds a year in Wisconsin, while one or two birds per commercial turbine are killed each year. One feral cat kills as many birds in one week as a commercial wind turbine does in three years of operating time,” Sagrillo said, putting this common concern about windmills into perspective. “Every window in your house is responsible for the death of one bird, minimum, a year. If we seriously want to save birds, we should be considering outlawing cats and windows, not wind turbines.”

Are you on the grid or off the grid?
“Off the grid” means that you don’t rely on public utility systems for electricity (or, in most cases, water and sewage either). Most people who are off the grid (at least those living in the United States), rely on some combination of alternative energy such as wind, photovoltaic or hydro. For these individuals, a wind system typically includes a control panel serving a bank of batteries that store generated electricity, and an inverter that converts the DC (direct current) power into AC (alternating current) before it is enters a breaker box and individual AC outlets.

Sagrillo pointed out that many homeowners are already tied to the grid (public utility system), yet they would rather be running on wind power than contributing to the environmental problems associated with rampant use of non-renewables. For these people, the Public Utility Regulatory Policies Act (part of the National Energy Act passed in 1979 under the Carter administration) allows for you to tie your alternative energy system right up to your local utility. In some states, you can even “sell” them back any excess electricity you generate.

Most state laws allow for the banking of excess electrical generation rather than selling it.
“When producing excess electricity, the meter runs backwards,” Sagrillo explained. “When the wind has died down and you are consuming that energy, you use that credit back up again.”

But utility companies are not always the most cooperative, he said.

“Utilities sort of view you as competition. There’s no grocery store in the world that’s going to tell you to go out and grow your own vegetables. Why do we think that utilities are going to encourage us to generate our own electricity?”

And the economics of the arrangement are skewed toward the utilities, Sagrillo said. “Anything you consume that you’ve offset is worth retail, but anything over that is wholesale,” he said. In other words, Sagrillo said, there’s no money to be made in selling back power to the big boys. “You’re not going to win, so you plan to use all the electricity that you produce.”

The good news is that required contracts typically protect consumers more than utility companies, Sagrillo said. “They have signed a contract with you, effectively admitting that they condone what you are doing.”

Some of these utility “intertie” systems, as they are called, also have battery backup, Sagrillo said, which causes utilities some level of concern. “That’s a huge amount of current that can be dispatched,” Sagrillo said. “You could backfeed it into the utilities. Who’s going to know?” (One of the concerns, and a valid one, Sagrillo said, is that utility workers could be injured when they go to work on a “down” line they assume is dead, yet there’s power flowing the other way out of someone’s home. But today’s synchronous inverters—which convert DC power to utility grade AC—and induction generators contain a device called a line-activated contactor, he said, which shuts off when the utility is down and resumes the connection when it goes back up again.)

“One of the down sides of a grid [tied] system is your storage is on the grid,” Sagrillo said. “If the grid goes down, you don’t have electricity unless you’ve got batteries.” It’s not unrealistic to expect to spend $7,000 or $8,000 on a good battery bank and an inverter, Sagrillo said, and the batteries only last about 10 years.

Utility companies can be difficult to deal with, Sagrillo said, suggesting that it often pays to get the scoop on state regulations guiding grid intertie systems from your state’s Public Utility Commission before approaching your local utility. Another strategy he suggested for pealing back the red tape is to find out if your utility company has ever participated in a wind power or photovoltaic project and then seek out the person who was in charge.

Getting money from your rich Uncle (Sam)
On the subject of so-called green energy—consumers opting to buy electricity from utilities that has been produced alternatively—Sagrillo was a bit sour. “I am not a fan of green power,” he said. “The message is that you have to pay a premium for renewables because they’re not cost-effective, and that’s sending the wrong message.”

Zoning setback requirements often mandate that a windmill remain within an owner’s property line in the event that it topples. Some zoning boards consider a windmill an attractive nuisance (meaning children may be draw to climb it) and may ask that you reduce the potential for accidents by surrounding your wind system with a fence.

According to a July/August 2002 Mother Jones cover story entitled Prevailing Winds, the cost of wind-generated electricity dropped 80 percent between the late 1970s and 2002 and, in some areas, is already outstripping the price of producing electricity with conventional fuels. And a federal tax credit of 1.8 cents per kilowatt hour currently being considered by Congress would lower the cost of wind generated electricity by another 30 percent. (Unfortunately for homeowners and farmers, the production tax credit is only available to corporations that are in the business of generating electricity.)

Federal programs are already on the books offering a number of incentives for investing in wind power, particularly in rural areas. The 2002 Farm Bill made available $115 million to help farmers, ranchers, and rural small businesses develop renewable energy project and to make energy saving improvements.

On May 5, USDA Rural Development announced that $22.8 million in grant funds were available for 2004. These funds are competitive and cap out at 24 percent of a project’s cost for projects between $10,000 and $2 million. For wind power projects, this can run the gamut from home- or farm-sized turbines up to co-op utility systems (with a maximum project size of about 2 megawatts). The application deadline is July 19, 2004. Find the full details of this grant published in the Federal Register.

The USDA Rural Utility Service also offers low-cost financing to rural electric cooperatives. And the U.S. Department of Energy’s Wind Powering America Initiative is seeking partnerships nationwide, including with those willing to form rural utility cooperatives, in order to increase the country’s use of wind power.

Many states offer major economic incentives for development of residential and on-farm wind power as well, including income tax credits, property and state sales tax exemptions, loan programs, and grants. Find a comprehensive state-by-state list of these programs at The Database of State Incentives for Renewable Energy (DSIRE).

Zoning regulations and setback requirements
You will often need to visit your local zoning board for a conditional use permit or a variance before erecting a wind energy system of any size, Sagrillo said. Building good relationships—both with local regulatory authorities and with neighbors who might hold objections to your project—is critical, he said. Be prepared to assuage people’s trepidations about wind power by educating them about the benefits of renewable energy, and be ready to take this campaign strategy to your zoning hearing, Sagrillo said. Fact sheets that tackle common concerns such as bird kills, television reception, property values, noise and lightning can also be a good idea, he suggested.

While wind-generated electricity has its detractors–including those worried about rural aesthetics and perceived danger to wildlife–it is increasingly apparent that status-quo options such as coal-fired electric plants promise dire environmental consequences.

A typical setback requirement assures that if a wind system topples it remains on the owner’s property, Sagrillo said. This often translates to a restriction that the tower not be built any closer to the property line than a distance equal to the tower height plus the length of one blade. (The FAA has its own restrictions concerning tower height. Any object higher than 200 feet must be reported. And if you are within 3.75 miles of an airport runway, you must contact your local FAA office to see if you need to file for permission to erect a tower of any height.)

Other objections that might come up at a zoning hearing, Sagrillo said, might be based upon:

• Aesthetic grounds. Be ready to point out the similarity between a wind tower and existing communications towers, or even grain elevators and silos, he said.

• Unfair comparisons to wind farms. One farm-scale turbine does not make a wind farm, Sagrillo asserted.

• Concerns of abandonment. While it introduced some sound energy policy, Sagrillo said, the Carter tax credit era also brought with it undeveloped technology, the relics of which are now eyesores upon the landscape. Be prepared to assure potential detractors that the wind industry has matured, that windmills have long warranties and longer life spans, and that you do not intend to neglect your investment.

• “Flying ice”. Ice buildup causes the blades to slow way down, and it is proper protocol to shut the machine off to prevent damage. Therefore, ice typically falls either not very far to the side or straight down (and typically gradually rather than in large sheets or chunks). You are more likely to be hurt by ice falling from a tree, said Sagrillo, since outstretched branches are susceptible to breakage.

• Questionable structural integrity of the tower. Bring along documentation supplied by your manufacturer or dealer, Sagrillo said.

• Noise. You can pick up the sound a wind turbine makes from surrounding noise if you really try, Sagrillo said, but today’s manufacturers pride themselves on quiet machines. Again, bring the specs along.

• That a windmill is an attractive nuisance, meaning a child might be drawn to climb it and become injured. Again, Sagrillo said, offer comparisons to other existing structures in the community, such as silos, and be prepared to resist any fencing-in requirements by drawing on such comparisons.

Such resistance is often the product of society’s exodus from city to country, Sagrillo said. “One of the biggest problems is that people who come out from the city have this romantic idea about what country living is,” he said. “When you start spreading manure, they don’t want any part of it.”

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