The winds of change are blowing toward Contra Costa County regulation of new wind turbines, and county officials want to make sure the big energy machines don't create a safety risk to motorists driving by them on a busy commute route south of Byron.

The goal of promoting clean, renewable energy while protecting public safety will be discussed Tuesday when the county board of supervisors considers revamping its wind turbine development rule for the first time since 1985.

Back then, in the infancy of the industry, turbines converting wind into electricity were smaller, less powerful and reliable, and often placed in locations prone to fatally hacking eagles, hawks and owls.

County planners and wind energy officials say it's time to modernize the ordinance to accommodate the new generation of larger turbines.

County Supervisor Mary Piepho, of Discovery Bay, however, said she wants to make sure the sight of new turbines doesn't create a distraction to motorists traveling on busy Vasco Road. Parts of the road south of Brentwood are adjacent to areas where new turbines as tall as 427 feet are proposed.

"We all recognize the benefits of green, clean energy and protecting hawks and other birds," said Piepho, who has worked for years to reduce auto collision risks on the accident-prone Vasco Road. "We also need to make sure we protect public safety."


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Piepho said she wants to make sure the turbines are far enough away from Vasco Road that any turbine blades that come loose wouldn't fly into motorists.

A wind company representative said he knows of no evidence that large turbines along public roads have caused distracted drivers to crash.

"We can't find data on this," said Eric Zell, consultant to the NextEra wind company, which proposes to replace its 438 old turbines with 34 large new ones in the Vasco Road corridor. "It's very subjective. We can't find information on this as a risk."

His wind company backs a proposed change in the county ordinance that would provide flexibility to a setback requirement that could threaten NextEra's plans for three of the 34 turbines.

Under the old restriction, new turbines must be placed away from the nearest public road at a distance that is at least three times the height of the turbine.

Older structures 100 feet tall would have to observe a 300 feet buffer. But a new wind turbine 427 feet tall would have to be built at least 1,281 feet away from a road -- nearly a quarter of a mile.

"Unnecessarily deep setbacks can cause significant difficulty in sitting turbines," the county's Conservation and Development Department wrote in a report.

The current setback rule could prevent a wind farm developer from making use of the best turbine sites to produce the most energy or cause the least risk to eagles or hawks, county planners said.

Other counties, including Alameda and Solano, have setback requirements. Unlike Contra Costa, however, the other counties have exemptions for smaller setbacks.

County planners recommend creating a new procedure to seek a smaller setback if a turbine would not create a significant danger, and if a reduced setback would reduce the risk to birds or increase power-generating capacity.

Zell, the wind company spokesman, said blades on new turbines don't travel as far as old turbine blades when they come loose and fly off. The reason: The newer blades are heavier and bulkier.

He said a NextEra consultant did a study concluding that a blade thrown off his company's turbine proposed closest to Vasco Road would not make it to the road. And the odds of a blade coming loose and flying off are remote, Zell said.

According to a draft environment report on NextEra's wind farm modernization, the risk of a blade throw is "less than significant."

NextEra, which also operates many Altamont Pass turbines in Alameda County, hopes that county supervisors will approve the ordinance changes soon so the company can take its project application next month to the county Planning Commission, Zell said. The ordinance had been scheduled to go to the board last month, but it was postponed to 10:30 a.m. Tuesday to allow for further consideration of the safety risk.

Piepho said she wants to make sure any new ordinance also protects Vasco Road motorists.

"Wind turbines are still a pioneering industry," Piepho said. "We're looking at a broad ordinance, but we also have to consider the circumstances around Vasco Road."

Contact Denis Cuff at 925-943-8267.

if you go
The Contra Costa County Board of Supervisors will hold a public hearing and possible vote on its wind turbine ordinance at 10:30 a.m. Tuesday in the County Administration Building, 651 Pine St., Martinez. Go to www.co.contra-costa.ca.us for more information.