A wind farm’s blinking red obstruction lights are a necessary safety measure to ensure wind turbines – which can measure from 400 to 550 feet in height – are visible to pilots and their aircraft. However, the intensity of these beams can also be an irritant to nearby residents, as the lights blink in contrast against the night sky. But thanks to advances in obstruction lighting technology, suppliers are introducing new products that flash only when necessary. The improvements are part of a growing trend to make obstruction lighting programs less intrusive.
The strength of these lights has some communities shying away from wanting a wind farm in close proximity to residential areas, fearing the lights will disrupt their sleep and their lives – an issue several wind power technology companies are trying to solve.
Over the years, numerous changes have been adopted to mitigate the nuisance caused by the lights. Early technologies, such as incandescent lighting options, have since been swapped for the more efficient LED technology, minimizing the light’s ground scatter.
On the regulatory front, the Federal Aviation Administration (FAA) and Transport Canada, which regulates Canadian airspace, put rules in place to ensure synchronization of the lights and maximum distances between lit turbines in an effort to reduce the light pollution over the night sky.
The first radar technology was introduced in the late 2000s when Norwegian company Obstacle Collision Avoidance System (OCAS) unveiled ground-based radar technology to the market. OCAS was acquired by Vestas in 2011.
New York-based Laufer Wind has developed its own radar-activated lighting technology called Aircraft Detection Sight Solution, which uses radar technology to identify an aircraft’s presence at night, switching the lights on as needed and having them off the rest of the time.
The company has been in talks with the FAA since 2008 and is confident the system will be a part of future wind farm installations because of the balance it strikes between current safety regulation requirements and light pollution complaints.
Companies, such as Montreal-based Technostrobe, designed a dimming solution to alleviate the disruption caused by a turbine’s lights. Their objective is to make these technologies available to future wind farm developers and ultimately help projects gain more community acceptance.
“The purpose of this is simple: It’s to help make wind farms more community friendly,” says Francis Lacombe, vice president at Technostrobe. He adds that people are torn between their desire for clean energy solutions and the disruption these lights may cause.
“It’s one of the irritants associated with a wind farm,” he explains. “The idea here is that if we’re attentive to these irritants, we can find imaginative solutions either from a social point of view or from a technical point of view to bring a greater level of acceptance for the wind farm.”
Technostrobe’s Lighting Intensity Dimming Solutions (LIDS) technology tailors the intensity of the wind farm’s lights using sensors that are situated around the perimeter of the wind farm that can detect the visibility conditions. The information gathered by the sensors is then sent to a central processing unit (CPU) in the farm’s substation. Once that condition is determined, the CPU sends a message to the lights on the wind farms, telling them at what intensity to operate.
Manufactured by wind industry experts in lighting and meteorology, LIDS allows turbine lights to reduce intensity on a clear day (visibility of 10 km or more) and increase strength in lower visibility conditions.
“We’re doing some trials with this, and between October 2013 and April 2014, we actually had statistics come back to us saying the lights would have functioned in a dimmed mode 91 percent of the time,” says Lacombe. “In fact, they would have been in the lowest intensity 85 percent of the time, so what that means is that most of the time, we’re flashing way above what is necessary for safety. When Transport Canada and the FAA designed the standards, there was no dimming option.”
There are, however, some concerns from regulatory bodies about these lighting technologies, explains Eduard Alf, senior engineer of aviation lighting systems at Transport Canada’s flight standards division.
Right now, Transport Canada allows for radar technology on wind farms as part of its rules associated with Aircraft Detection Systems. According to the regulations found in Chapter 15 of General Operation and Flight Rules, the system “can detect and analyze the flight path [position, altitude, heading and ground speed] of an aircraft so as to determine the possibility of potential collision with an object.”
“The radar system, it works – but it’s very costly, and that’s one of the problems,” says Alf, adding he isn’t confident that dimming the lights will ease the number of complaints among residents in close proximity to the wind farms.
“Although, in effect, it’s not a matter of the intensity; it’s truly a matter of the light being out there anyway. I’ve found that people will complain about lights even though there really isn’t that much light actually reaching them.”
Shant Dokouzian, senior project manager at DNV GL, echoes Alf’s point that residential complaints do not always subside despite regulatory or technological changes.
“I think that new technology which diminishes the intensity of the light depending on visibility is definitely a good idea. My understanding of Transport Canada regulations is that obstruction lights need to have a high intensity for days when visibility is pretty low,” he says. “A worst-case scenario.” w
Marketplace: Obstruction Lighting
Obstruction Lighting Advances Make Turbines Better Neighbors
By Daina Lawrence
Intent on making wind turbines less obtrusive, obstruction lighting providers continue to improve the technology.
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