Last May, 10 one-kilowatt wind turbines were installed on top of the Becton Engineering and Applied Science Center to remind passing Yalies of the University’s sustainability efforts. But almost a year later, the turbines’ actual economic and energy savings value is still unclear.
While Tom Downing, the Office of Facilities’ senior energy engineer, said the turbines will pay for themselves, not including the cost of installation, in about eight years, two Yale engineering faculty members interviewed said they are skeptical the small turbines can generate enough electricity to be cost-effective.
The turbines — meant to serve as a sign of Yale’s commitment to reduce greenhouse gas emissions 43 percent below 2005 levels by 2020 — were built by the energy firm AeroVironment, Inc., and cost $5,000 each, Downing said. He said the manufacturers estimated the turbines would generate about 26,000 kilowatt hours of electricity annually, which is equal to or about half of 1 percent of the Becton Center’s annual electricity needs and will reduce the University’s carbon dioxide emissions by about 20,000 pounds. (This data is based on the assumption that the turbines will be spinning about 30 percent of the time over a one-year period, Downing said.)
But engineering and applied physics professor Paul Fleury and engineering design advisor and lecturer Glenn Weston-Murphy said they are skeptical about the turbines’ efficiency. To have an energy-saving impact, there would need to be many more small turbines on top of Becton Center, which is not feasible because of limited space and zoning issues, Fleury said.
“I don’t know where the 26 megawatt hours came from, but it is at best very optimistic,” Weston-Murphy said, adding that he did not know whether the turbines would ever pay for themselves completely.
So far there have been no reliable data on the electricity actually generated by the turbines, Downing said. The energy yield of 916.77 kilowatt hours currently listed on the turbines’ “SunnyWeb Box” Web site, which tracks real-time statistics about the turbines, is not accurate because of communication problems between the SunnyWeb Box system and the turbines.
Downing said workers will come next week to upgrade the turbines and to fix the issue with energy tracking. Furthermore, a weather station has been installed on the Becton Center to allow students to research the impact of wind conditions on turbine performance, he said.
While the wind turbines may not necessarily be cost-effective, they have been important for advocating sustainability at Yale, Weston-Murphy said; the turbines have brought attention to wind energy on campus, he said.
While the turbines were originally going to be installed on top of the sidewalk canopy between Kline Biology Tower and Sloane Physics Laboratory, safety concerns about the turbines being too low to the ground led the Office of Facilities to consider the Becton Center, which had the added benefit of greater visibility, Downing said. So far, Downing has given about a half-dozen tours on the roof of Becton Center, he said.
Fleury and Weston-Murphy said they are looking forward to the future of wind turbines at Yale. Wind energy can be converted into electrical energy at up to 95 percent efficiency, Fleury said. For almost two years, Weston-Murphy has been analyzing wind patterns on the West Campus using sodar, which uses sound waves to measure wind speed. He said he would like to see a wind turbine installed on West Campus. Such a turbine could generate up to 3,000 megawatt hours per year, he said, and could pay for itself in under 10 years because it would be much larger and more efficient than the Becton turbines.
“It would light a lot of light bulbs,” Weston-Murphy said.
While Downing said the Office of Facilities has no immediate plans to install more turbines on University property, he said that if opportunities present themselves, the office will consider them.
There have been no reports of bird deaths caused by the turbines.
Correction: April 6, 2010
An earlier version of this article misreported that engineering design advisor and lecturer Glenn-Weston Murphy is a 1971 graduate of Yale College. In fact, Weston-Murphy did not graduate from Yale.