Secretary of the Interior Ken Salazar, speaking in Atlantic City on April 6, added more hot air to the discussion about offshore wind when he stated that windmills off the East Coast could generate enough electricity to replace most, if not all, of the coal-fired power plants in the U.S. I’m disappointed Salazar didn’t take a few minutes for fact-checking and back-of-the-envelope ciphering before his speech.

Developing New Policy

Salazar was speaking at the first of four hearings scheduled around the country to discuss resource planning and what role our nation’s offshore energy resources — specifically natural gas, oil, and wind — will play in future energy legislation contemplated by the Obama administration. During his presentation, Salazar said, "With respect to renewable energy, there is tremendous potential concerning wind off the Atlantic." He added, "there is over 1,000 GW of power or 1,000,000 MW of power developable off the Atlantic coast" that is "the equivalent of energy produced from 3,000 medium-sized coal-fired power plants."

Part of me believes that Salazar really doesn’t expect that wind power parks along the eastern shore are "developable" to the degree he described, but that his statements were meant to engage the audience to consider the possibilities of offshore wind. The other part of me is very concerned that many listeners will selectively hear only the punch line: The developable potential for wind turbines off the east coast is equivalent to 3,000 mid-size coal-fired power plants, so therefore wind turbines off the Atlantic coast can replace all of our coal plants. I hope future energy policy will be more circumspect.

First, let’s clear up a misconception that could be created by Salazar’s statement. The U.S. does not have 3,000 coal plants. The Energy Information Administration (EIA) website, which provides the best data available, shows that at the end of 2007 (the last year for which data are available) there were 1,470 coal-fired plants in the U.S. with a nameplate capacity of 336 GW. Also, coal-fired plants account for 30.9% the nation’s total power resources with a net summer capability of 995 GW. More importantly, coal fired over 48.5% of the total generated electricity that year, as it continues to do today.

Unfounded Estimates

The EIA website also reveals that wind generated 42.1% of the nation’s renewable electricity in 2008. Renewables, less hydroelectric power, generated 3.0% of our electricity in 2008, so wind supplied 1.27% of our electricity needs. I’m not prepared to make the mental leap from the small contribution wind power makes today — with no U.S. offshore turbines — to an energy source capable of supplying all the nation’s electricity.

If we were to accept Salazar’s vision of the potential for offshore wind, the entire 1,800-mile length of the Atlantic coast would be filled with wind turbines to replace our 1,470 coal plants and more than 15,000 other power plants. Ignoring the obvious transmission and distribution difficulties, the cost of these installations, and the price of the power produced, a little elementary school math reveals Salazar’s vision as a fantasy.

As a template, consider the Cape Wind project, located in Nantucket Sound, which only recently received approval to proceed after battling government regulators for years. Cape Wind consists of 130 wind turbines, each rated at 3.25 MW, arranged in a grid pattern of parallel rows for a total of 420 MW. Within a row, each turbine is located 0.34 miles apart, and the rows are a little over half a mile apart, when viewed from Nantucket.

If we assume the entire eastern coastline were open to development, then there is room for 3,600 wind turbines, one row deep. Also, if the rating of all these new turbines were the same as for Cape Wind, then to replace the entire nation’s installed capacity with a like amount of offshore capacity requires 334,462 wind turbines. In other words, the entire east coast would have wind turbines located every half-mile and 93 turbines deep (over 30 miles) out to sea.

Not a 1:1 Replacement Option

Salazar stated that 1,000 GW of East Coast offshore wind turbines could replace 100% of our nation’s electricity supplies (approximately 1,000 GW). He gave the same estimate of offshore wind power potential in testimony to the Senate’s Energy and Natural Resource Committee on March 17. But a typical offshore wind park along the Atlantic coast would have a capacity factor of less than 30%, compared to a capacity factor for our coal and nuclear fleet in excess of 80%. That means to replace 1 kW of coal or nuclear capacity, you would need nearly 3 kW of rated wind capacity — and that’s not even considering the obvious production timing issues.

What about the cost of offshore wind power? The Ocean Energy Institute about a year ago proposed a giant 5,000-MW offshore wind farm in the Gulf of Maine estimated to cost $5,000/kW. Extrapolating that estimate to 334,462 wind turbines I calculated above produces an estimate with so many zeroes my calculator gives me a zero overflow error.

I believe that our future energy policy should include the private development of those offshore locations that can be economically developed, like the Cape Wind project. However, to represent offshore wind as capable of supplying the nation’s entire electricity needs is just pure bluster.