Be Realistic

In the past year, I’ve seen these wind-electric installations:

 ✓ A $15,000 installation of a 12-foot turbine on a much too short (33-foot)

tower generating 250 kWh per year for a simple payback of about 220

years. Cost of energy: about $1.30 per kilowatt-hour, or about 6 times the

local utility cost.

 ✓ A $30,000 installation of two 12-foot turbines on 33-foot towers below the

tree line, which will likely produce only a very few kilowatt-hours and

have a payback of several hundred years, if the turbines last that long.

Cost of energy: $5 or more per kilowatt-hour, or at least 25 times the

local utility cost.

 ✓ A $90,000 installation of a 21-foot turbine on a 60-foot tower generating

only 750 kWh per year for a simple payback of 1,000+ years. Cost of

energy: about $4 per kWh, or 40 times local utility cost.

Now I’m the first to say that money isn’t everything. I don’t even think it’s the

most important thing. But I don’t think the buyers of these systems would

have made the purchases if they’d been realistic upfront. And that means

they would avoid the serious disappointments that resulted.

 Do at least some rudimentary calculations of return on investment (discussed

in Chapter 10) so that you know what you’re getting into before you buy!

Use a Tall Tower

Being realistic requires tall towers on almost all sites. The bad examples and

experiences in the preceding section were all a result of towers that were

short — much too short. You can ruin your prospects for making a lot of wind

energy in other ways, but putting your wind generator on too short a tower is

the most common. It’s a mistake that the wind-electric industry has yet to learn

from entirely. It continues to have companies coming in and advertising prod-

ucts and installation methods that try to defy the physics of wind.

But defying physics works better in the movies than in the real world. The

reality outside the TV box is that

 ✓ Wind energy increases with the cube of the wind speed (V3)

 ✓ Wind speeds increase as you move away from the Earth and its

obstructions