Wind-Power Noise can be ‘Annoying’

By SARAH SCHUMANN/ecoRI News contributor

NARRAGANSETT, R.I. — The Rhode Island Renewable Energy Siting Partnership recently hosted the fourth in a series of stakeholder meetings focused on land-based wind energy. The meeting examined two topics vital to wind energy siting and permitting: the acoustic effects of wind turbines and the economics of wind-energy production.

The Rhode Island Renewable Energy Siting Partnership (RESP) is a joint project of the Rhode Island Office of Energy Resources and the University of Rhode Island that was launched in September. At the heart of the project is a three-part public engagement process modeled after the practice employed by the Ocean Special Area Management Plan (Ocean SAMP) from 2008-10.

A first round of meetings was held earlier this fall to identify issues important to the public in the siting of wind power and other renewable energy technologies. Now in its second round, the partnership is hosting lectures by local wind-energy experts on key issues of concern identified during the first phase.

The Dec. 1 lectures were delivered by two URI professors: Gopu Potty, Ph.D., of the Department of Ocean Engineering and James Opaluch, Ph.D., of the Department of Environmental Resource Economics.

Potty gave an overview of the science used to assess acoustic impacts of land-based, wind-energy facilities. The effect of noise from a wind-power facility depends on multiple factors, Potty said, including humidity, temperature, ground cover, and the presence of trees and buildings that alter the noise level as it travels from the source.

A key point of Potty’s lecture was that the acoustics of wind turbines are highly subjective. People perceive wind-turbine noise to be as annoying as aircraft noise, he said, even though it’s not nearly as loud.

Wind-turbine noise can be annoying for several reasons, Potty said. The variation of wind speeds makes the noise unpredictable. The rotation of the blades gives rise to a “swishing” sound, which tends to be more annoying than a uniform noise level — this effect is canceled out by the presence of multiple turbines.

A third reason highlights the subjectivity of noise perception. The fact that wind turbines can be seen, Potty said, causes people to pay more attention to the noise they give off. As the RESP project continues, Potty said, it will be important to develop metrics to quantify this subjective “annoyance factor” for use in siting studies.

Opaluch’s lecture showcased a variety of different tools for estimating the economics of potential wind-power projects. Studies of wind-power economics fall into two categories, he said. The first assesses project costs and revenues associated with building, operating and maintaining a wind-power facility. The second looks at economic impacts on the regional economy, including jobs created, income generated and money spent in the region by people employed by the facility.

The federal government has developed many tools to assess the economics of wind energy, Opulach said. The next step for the RESP is to validate some of these tools in a Rhode Island context, and to develop a user-friendly, online “back of envelope” tool to enable Rhode Islanders to gauge for themselves the potential economic effects of wind-power projects in the state.

The Dec. 1 session wrapped up with a group discussion on the informational needs of the stakeholders present. Participants asked for more data on the effects of wind-power projects on utility ratepayers, on mitigation of the noise given off by wind turbines, on the economics of connecting wind power to the grid, and on how the costs of permitting can be lessened so as to make wind-power development more feasible for household operators.

RESP member institutions also are working to quantify the effects of land-based wind energy on birds and bats, to assess the impacts of flicker and electromagnetic fields, and to assist state agencies and municipalities in coming up with guidelines to regulate the emerging wind-energy industry. They will also look at solar and small-scale hydropower opportunities. By the time the project ends, in March 2012, the partnership will unveil a one-stop, comprehensive online database of renewable energy possibilities in Rhode Island.

“Our job is not to do the homework of the developers,” said URI’s Danny Musher, one of the coordinators of the RESP. “Our job is to provide information to empower citizens and to do the work that others can’t afford to do. We’ll help bridge that gap.”