Not so fast. The claim that Rock Port is fully wind-powered may be, at best, a bit exaggerated.
The mainstream press has picked up this report from the University of Missouri Extension office (reported by Science Daily) claiming that Rock Port, Missouri is the first 100% wind-powered city. On paper it looks all well and good, but when it comes down to the specifics, it simply isn’t true (emphasis mine):
Rock Port Missouri, with a population of just over 1,300 residents, has announced that it is the first 100% wind powered community in the United States. Four wind turbines supply all the electricity for the small town.
Rock Port’s 100% wind power status is due to four wind turbines located on agricultural lands within the city limits of Rock Port (Atchison County). The city of Rock Port uses approximately 13 million kilowatt hours of electricity each year. It is predicted that these four turbines will produce 16 million kilowatt hours each year.
While it may be the case that the wind turbines will, over the course of one year, generate as much power as the community will use in one year, it simply isn’t true that the town could go “off the grid” entirely.
Wind turbines generate power on an intermittent basis. When the wind is blowing, the turbines spin and spit out a nice stream of electricity. But on calm days (or wind speeds below a given threshold), the turbines generate little to no electricity. The power output generated by a wind turbine is far from constant, and as such, it simply cannot be utilized as the only source of power for a community. In the current Rock Port setup, when the wind turbines generate power in excess of what the town is utilizing at the time, the excess power is “sold” to the grid:
Excess wind generated electricity not used by Rock Port homes and businesses is expected to be move onto the transmission lines to be purchased by the Missouri Joint Municipal Utilities for use in other areas.
Alternatively, when the wind is calm, the town does not go dark. That connection to the grid is not one way. The 1,300 residents then depend on pulling power from the rest of the grid (power not generated by wind but rather from more traditional sources) to sustain a constant flow of electricity. As such, absent the use of multiple, gigantic, expensive batteries to store the excess electricity generated on windy days to tap when the wind is calm, it cannot be claimed the city is “100% wind powered” under the current scenario.
Furthermore, such development is simply not economically viable in its current state. While funding sources have not been entirely transparent, it has been reported that the wind farm that is powering Rock Port (built by Wind Capital Group) required $90 million dollars in start-up capital. Divided among the 1,300 residents of Rock Port, that would necessitate an up-front investment of nearly $70,000 per resident to say nothing of ongoing maintenance costs.
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For more on the original report:
University of Missouri Extension (2008, July 16). Rock Port, Missouri, First 100 Percent Wind-powered Community In U.S.. ScienceDaily. Retrieved July 16, 2008, from http://www.sciencedaily.com /releases/2008/07/080715165441.htm