TCS Daily

Gone With the Wind

By Sallie Baliunas - September 25, 2002 12:00 AM

So-called renewable sources of electricity are being considered in this fall's energy legislation negotiations. One proposal, in Senate bill S. 517, mandates that renewable sources - for example, wind and solar but excluding new hydro - supply 10% of the electricity from most utilities by the year 2020. Some states have already imposed quotas for new, non-hydroelectric renewables on utilities.

But wind and solar should be dubbed disrupters, rather than renewables. Why? As energy sources they devour the environment.

Potent Potential

Coal, uranium, natural gas, petroleum products and hydro currently produce over 97% of U.S. electricity, with coal the major share. The Energy Information Agency forecasts that electricity consumption in the U.S. will grow nearly 50% by 2020.

Wind supplies a tiny fraction of electricity at present, and EIA forecasts that by 2020 wind and sunlight together would still meet less than 1% of U.S. electricity needs, absent quotas other than those that states have already imposed. That means wind and solar will not meet needed U.S. electricity growth.

Could stricter mandates force fuel switching from fossil fuels to wind? Yes, at a cost. At first glance, wind power seems attractive. Wind is abundant, and wind towers (after they are manufactured) generate power free of carbon dioxide emission and local pollutants like oxides of nitrogen and sulfur that result from fossil fuel combustion. The U.S. has bountiful wind resources - North Dakota, Texas, Kansas, South Dakota and Montana rank in the top five states for wind potential.

While the potential for wind power is enormous across the U.S., realizing that potential is difficult and expensive. The reasons are several.

Wind is dilute. The power delivered by a tower depends on the sweep of the blade - the longer the blade, the more power possible. To generate electricity cost effectively, towers are typically 200 to 300 feet tall with blades over 100 feet long. Many towers can be ganged together to reap cost-effectiveness with infrastructure such as maintenance roads, firefighting facilities, weather stations and high-power transmission lines. But towers must stand distanced from local irregularities like trees, buildings and other towers, in order that the wind flow smoothly around the blades.

Power output depends on the cube of wind speed. A small drop in wind speed - e.g., a 10 mph decrease from 30 mph to 20 mph - means that power declines over 70%. To make up for the intermittency of wind, numerous towers would have to be built in many locations such that wind would always be blowing somewhere.

Massive Footprint

The towers themselves do not take much land area. Some activities, like ranching, could go on among an army of towers. But the towers are noisy and prone to lightning strikes. The blades may throw ice or other debris, which further emphasizes the need for distance from civilization.

The whirling blades are invisible to some birds, which caused the Audubon Society to label wind towers "condor cuisinarts." While future technology may yield blades that birds could avoid, siting must for now be habitat-sensitive in order to avoid bird kills, especially of endangered species. For towers anchored at sea, their vibration and oil spills from their generators may harm ocean life and ecology.

Towers are aviation hazards and must be lit at night. In the case of off-shore wind farms, the towers are navigation hazards also requiring lighting.

And a comparison with alternative energy sources is instructive. Horseshoe Shoal, off Cape Cod, is a proposed wind station that would occupy approximately 25 square miles, with 170 towers each 426 feet tall, blade diameter 328 feet long (the Statue of Liberty is only 305 feet high), and lit by a total of 680 navigation lights. How does the power this wind station would produce on average (the wind blows at varying speed) compare to that of a coal or natural gas power plant of average 1000 Megawatts (1 Gigawatt) and spanning tens of acres of land? To produce the equivalent power would require over 1,700 towers covering 250 square miles. The Arklow Sandbank off the shore of Ireland would be roughly similar in number of towers and expanse. Further, wind towers require maintenance access (on land, roads must be built to reach each tower, and at sea, ships motor to each tower), fire fighting facilities, meteorological stations and high power transmission lines to deliver electricity from towers widely scattered through their isolated sites to customers.

Negative response to large-scale wind projects is growing. The Bishop of Hereford, who is the environmental spokesperson for the Church of England, recently said of the planned Cefn Croes project in Wales, which would produce 0.023% of the electricity for the U.K.: "I am resolutely opposed to the myopic, cynical, short-term reliance on the so-called proven technology of onshore wind, with its hideous despoilation of the landscape, its invasion by monstrous turbines of a totally alien industrial character, with their maddening noise and relentlessly disturbing movements." (March 14, 2002, This Is Herefordshire)

The vast area necessary to collect the wind's dilute resources is why towers should be viewed as disruptive, rather than renewable, resources. A few ideal, pristine locations will be developed first. But the next round of site selection would face a more demanding trade-off between expense and habitat, thus limiting the production of wind electricity. Depending on the local wind conditions and the type of wind towers, by 2020 the U.S. would need approximately 50,000 to 100,000 towers, sitting on about 7,500 to over 10,000 square miles, in order to produce just 5% of its electricity by wind. That's an area roughly the size of Vermont.

Even enormous wind tower tracts are unlikely to provide significant amounts of reliable, quality, cost-effective electricity. And they will become unpopular. The invasion of hordes of ecosystem-demanding towers pocking the landscape will be seen as visual and ecological blights.

One more aspect of the destructive nature of wind and solar facilities is worth noting. Mandates for wind and solar power are usually accompanied by subsidies that are borne by utility ratepayers or taxpayers or both. In other words, quotas for environmentally-depleting energy sources are tantamount to a stealth BTU tax on electricity. The embrace of disruptive energy sources like wind and sunlight for generating meaningful, community-wide, quality supplies of electricity would be costly to the economy and the environment.



TCS Daily Archives