Environmental Impacts FAQs

The productivity of wind farms fluctuates with daily and seasonal wind speeds, but most wind farms produce at least some electricity most of the time. Wind farms are virtually always economically viable during the typical 20-year terms of their power purchase agreements. If decommissioning the Gosfield-Comber project were ever to be necessary, Brookfield Renewable Power would pay for these costs.

The lease agreements with landowners allow for two 20-year operating terms and a 7-year initial development period. The agreements enable landowners to receive royalty payments based on a percentage of the total gross revenue generated by the wind farm and payments for use of their land during construction, for crop losses on any of their property affected by the project and for any increases in property taxes.

The Ministry of Municipal Affairs and Housing has established the value of wind turbine generators to be based on the permanent portion of the equipment – an assessed value of $40,000 plus the value of one acre of land has been applied per MW. This value is multiplied by the local commercial tax mill rate to determine the property tax.

For the 149 turbines on agricultural land, the host municipalities could receive new tax revenue of approximately $300,000 per year, with no additional strain on municipal services.

The project is still being developed, and Brookfield Renewable Power has not yet assigned the on-site project manager who will be in charge of local contracting. As the project advances, there will be further public consultations and announcements regarding the progress and expected schedule of the project.

Property values increase for landowners who receive lease payments for wind turbines on their land.

For the project’s Environmental Screening Report and Impact Statement prepared by the independent experts engaged by Stantec Consulting Ltd., an analysis was conducted of the actual impacts of wind farms on surrounding property values in several countries:

Melancthon Township, Ontario

This review was carried out between November 2004 and November 2005 (before and after construction of the first phase of the wind farm), in two areas (one within the turbine siting area, and one outside the siting area) where 27 properties were sold. The review indicated that the average asking price was similar in the wind turbine siting area when compared to prices outside the area. The average sale price was higher in the turbine siting area. The average difference between asking and sale prices was lower within the siting area (i.e. positive position).

Melancthon and East Luther Grand Valley Townships, Ontario

Sales activity for the two comparable Townships (one with a wind farm, and one without) were analyzed before and after development of the wind farm in 2006. The key conclusions included:

• Prior to construction of the wind farm, property sale price levels were significantly lower in Melancthon than in East Luther Grand Valley.
• Following construction, registered sale prices increased in both Townships, but growth levels were significantly higher in Melancthon, which demonstrated consistent patterns of growth similar to Dufferin County, whereas East Luther Grand Valley demonstrated inferior growth compared to Dufferin County.
• The presence of a wind farm was not seen to have diminished property value, but to arguably have encouraged increases in property value.

Madison County, New York

According a 2006 study of 280 residential sales within 5 miles of a 20-turbine wind farm, there were no measurable effects of wind farm visibility on property transaction values, even for homes within 1 mile sold after construction in 2001.

Wind farms throughout the US

A systematic review in 2003 was undertaken for the Renewable Energy Policy Project – a government agency – of 14,800 property sales in view sheds (within 5 miles) of 10 wind farms and 9,500 property sales in comparable communities without wind farms. The results: property prices increased in 8 of 10 view sheds at an average rate double the rate of comparable communities without wind farms, and prices increased in 2 of 10 view sheds at an average rate half the rate of comparable communities. For 26 of the 30 analyses conducted, property values in the affected view sheds actually performed better than in comparable communities.

United Kingdom

The Royal Institution of Chartered Surveyors found that no studies within the country suggest an effect on property values either way (2002). At over 70 wind farms in the England, Wales and Scotland, available evidence demonstrates that they have no material effect on house prices.

Brookfield Renewable Power has retained independent consultants of Stantec Consulting Ltd. (Stantec) to conduct an Environmental Screening Process as required under Ontario Regulation 116/01 of the Environmental Assessment Act. To assess any potential impact on birds, other wildlife and natural habitats, Stantec’s ecologists and sub-contracted specialists have many years of experience and have completed numerous projects requiring environmental (noise, wildlife, socio-economic, archaeological, etc.) impact assessment, ecosystem planning and habitat restoration.

Turbines make mechanical noise, and an aerodynamic, “swoosh” noise when the blades pass the tower. However, recent advancements in turbine configurations, materials and blade geometry have made turbines relatively quiet.

Noise from a wind turbine is typically 35-40 decibels (dBA) at a distance of 300 metres with a wind speed of 8 metres/second. This compares to the noise of an office (35-50 dBA) or inside a residence (25-45 dBA). You can stand beneath an operating turbine and have a normal conversation (55-65 dBA) without raising your voice.

Blade noise increases with wind speed, but so do offsetting natural background noises such as “swishing or whistling” wind, rustling leaves or lapping waves.

Ontario's MOE applies some of the strictest noise guidelines for wind turbines of any jurisdiction in Canada.

The sound limits in decibels depend on the average wind speed and on type of urban or rural area. The sound limits in the interpretation document are consistent with the MOE criteria set in the technical publications titled "Sound Level Limits for Stationary Sources in Class 3 Areas (Rural) – Publication NPC-232" and "Sound Level Limits for Stationary Sources in Class 1 & 2 Areas (Urban) – Publication NPC-205", both available in the "publications" section of the Ministry of the Environment website.

Specific guidance is given in a document titled "Interpretation for applying MOE Technical Publications to Wind Turbine Generators". This document is available on the MOE website at: .

No – The sound limits apply for continuous operation any time of day or night. The Ministry recognizes that the more sensitive times for sound impacts typically occur during evening and night-time hours, so sound from wind turbines is limited to the maximum set for night-time hours in publications NPC-205 & NPC-232.

No, waivers and other legal agreements of this type are beyond the scope of the ministry’s interpretation document for wind turbines. Consequently, no other sound limits are accepted.

A landowner’s residence on the same property as a wind turbine(s) is not a Point of Reception as defined by the Ministry of the Environmentsound guidelines. Consequently, since that residence would be considered as part of the facility containing the wind turbine(s), no sound limit would apply. The newest Point of Reception is located on a neighbouring property.

A baseline ambient noise survey was conducted within the Gosfield-Comber project study area to substantiate the provincial regulatory sound level limit requirements for the project. According to the Environmental Noise Impact Assessment conducted by Aercoustics Engineering Ltd. for the recent Environmental Screening Report and Impact Statement:

• Noise impacts of the project’s wind turbines and transformer stations (with noise barrier walls) were predicted using acoustic modeling.
• The analysis showed that the impacts do not exceed the most restrictive night-time noise limits that apply for Class Rural areas as defined by the Ministry of Environment, and consequently, there is no need for application of additional mitigation measures.

Ministry of Environment staff have reviewed the sound assessment and found the results met all requirements.

No, the Certificate of Approval application would only be posted if the wind turbine project was not subject to the Environmental Assessment Act (i.e. if the project is less than 2 MW in nameplate capacity).

No, there is not a recommended minimum setback distance for sound limits.

The document titled “Interpretation for applying Ministry of Environment Technical Publications to Wind Turbine Generators” describes the requirements for setback distances of less than 1,000 metres. At distances farther than that, sound impact due to wind turbine operation is insignificant; consequently, a sound assessment is not required. However, the project is still subject to approval under section 9 of the Environmental Protection Act.

Many factors can influence sound impacts due to wind turbine operations, including wind gradient (speed and direction at various elevations), temperature inversions, ground effects such as topography, receptor height, molecular absorption in air, acoustic shielding, and reflections, amongst others.

Planning authorities (including municipalities and planning boards) may require additional assurances under the Planning Act, beyond what is required by provincial environmental legislation and guidelines. Most developers try to coordinate provincial and municipal sound requirements and address them in one sound assessment study and report.

No – There is no evidence that current wind turbine generators present any problems related to the generation of infrasound/low frequency sound. These sound emissions occurred with some early wind turbine models; however, this was attributed to early turbines with their blades downwind of the support tower. These emissions do not occur with modern upwind turbines with the blades upwind of the tower.

There is no evidence to indicate that modern wind turbines cause vibration. A failure of mechanical components may result in adverse mechanical sound and/or vibration. However, these are detected by turbine monitoring and notification devices and Brookfield Renewable Power will be performing regular inspection and maintenance of the turbines, to prevent or correct such conditions.

Residents should contact Brookfield Renewable Power (see contacts) or their local Ministry of Environment District Office, which can be found on the Ministry of the Environment website at http://www.ene.gov.on.ca/envision/org/op.htm .

Turbine technology has improved for avian species, with slower blade rotation speeds and tubular rather than lattice towers. Many studies of bird mortality and wind turbines indicate that the potential for bird mortality is low.

Gosfield-Comber Wind Energy Project

The following are conclusions drawn from 14 months of field studies in 2004 and 2005 in the project’s study area, additional studies conducted during the breeding season of 2007, and radar studies in 2005 and 2007, for the recent Environmental Screening Report and Impact Statement prepared by the independent experts engaged by Stantec Consulting Ltd:

• Scarcity of natural habitat generally results in low bird use in the project study area (i.e. the area does not support concentrations of wintering birds, nor significant concentrations of staging spring or fall migrants; flight activity during migration is approximately 25% lower than the North American average; over 80% of nocturnal migrants travel above the height of turbine blades),
• Given this scarcity and the minimum 17.5 km distance between the proposed turbines and known staging and stopover habitat, turbines in the study area are not expected to interfere with migrants’ ascent and descent,
• As a result, no significant direct mortality to migrants is anticipated.

Erie Shores Wind Farm 

The following are actual results from the post-construction avian monitoring program conducted by Dr. Ross James – former chief of ornithology at the Royal Ontario Museum. The wind farm is located near Port Burwell (south of Tillsonburg), where its 66 turbines are located within 3 km of the shores of the lake. Dr. James undertook 2 years of post-construction monitoring, revealing these findings:

• Swans, geese and ducks returned to the area in usual numbers during spring migration. Swans flew through the wind farm daily when present, and easily found fields to forage in. In the autumn, upwards of 300 geese daily fly from Lake Erie into or through the wind farm to forage in fields. They are often seen in the same fields as the turbines. No waterfowl have been found dead, although many geese have been seen flying past operating turbines within 100 m of them. 
• Bald Eagles nested just north of the wind farm in 2006 and raised two young to fledging. They returned to nest again in 2007. Immature and adult eagles fly back and forth daily as they forage along the lakeshore past the nearest turbines, often within 200 m of them. 
• Breeding bird surveys have not revealed any decrease in numbers of breeding birds adjacent to turbines. Smaller birds have readily nested close to turbines if there was suitable habitat. Killdeers, for example, were attracted to the new access roadways and nested as close as 4 m from the towers. Savannah Sparrows nested within 16 m, Vesper Sparrows within 30 m, Warbling Vireos within 24 m, Horned Larks within 15 m and Baltimore Orioles within 40 m. All of these under or nearly under the extent of the turbine blades. Among the larger birds, Mallards nested within 100 m, Red-tailed Hawks and Cooper's Hawks within 200 m. 
• The autumn migration of diurnal raptors has not been hindered in the least. Despite having watched thousands fly through the wind farm, only three dead in two years of searching were found. The turbines have not been the cause of any serious mortality. Very few raptor migrants ever get close enough to be at risk, although many may fly past within 100 m of the blades. The numbers of diurnal raptors flying past Hawk Cliff, a short way west of the wind farm was higher in 2006 than in previous years, indicating no change in migration numbers along the Lake Erie shores. 
• Hundreds of gulls daily fly along the lakeshore bluffs past the nearest wind turbines. At times hundreds are seen flying inland over and through the wind farm. Hundreds have been seen in fields, often the same fields as turbines, yet, in two years of searching there has been only one recorded death.
• Smaller diurnal migrants, such as jays, goldfinches, waxwings, buntings and blackbirds fly through the wind farm in the thousands each autumn, undeterred by the presence of the turbines. Despite the thousands seen in migration, not a single diurnal migrant has been found dead during the migration season. 
• As has been the case with any wind power installation, the majority of casualties are from the small nocturnal migrants. But the mortality at the Erie Shores site was not considered unusual by Dr. James. It will probably work out to be near the average found at other carefully studied North American installations. While that level of mortality may be regrettable, it is not a serious casualty rate, particularly when compared to far more serious things such as windows, house cats, or habitat loss. Searches were made at all turbines weekly, or more often, over 6 weeks in spring and over 7 weeks so far this autumn. Yet the number of dead birds incidentally identified on the roads this year, where no regular systematic surveying was done, has been three times higher than the number found under the turbines. 
• In two years of searching every turbine at least once a week, some more often, no mortality was observed at half the turbines.
• Over two years there have been birds found at 19 of the 66 turbines each year, and at only two of them was there mortality both years.
• Nearly half of all birds found were within 10 m of a tower (whether on the roads, at turbines where fields can be walked all year, or considering everything found), meaning there is a high probability of finding anything if it is there.
• At the 9 turbines nearest the shore, where mortality might be expected to be somewhat higher, birds were found at 5 turbines in 2007, and at only 2 turbines for both years.
• During 30% of the time spent searching during migration seasons (18 weeks), no birds were found at all.
• The unadjusted mortality rate for the Erie Shores Wind Farm, based on two years of post-construction monitoring, is estimated at 0.45 birds per turbine - small samples all around.

Alberta wind farms

A study of over a million, night-time flight paths in three dimensions at six Alberta wind farms and six control/non-windfarm sites in 2004 revealed that birds and bats detected wind turbines and flew higher and slower while approaching turbines.

Wind farms throughout the US

According to the US National Wind Coordinating Committee, an average 2.3 birds and 3.4 bats died per turbine per year at 12 wind farms studied across the country.

Another US study revealed that wind farms kill less than 1 bird for every 5,500 killed by reflective windows, 1,000 killed by domestic cats, 800 by high tension wires, 700 by vehicles, 700 by pesticides, and 250 by communication towers.

Also, the US National Audubon Society supports wind power rather than other types of power generation because its clean energy reduces pollution, acid rain, global warming – the most significant threats to birds and other wildlife.

Existing studies of wildlife and natural habitats similarly indicate minimal impacts.  

Of course, the amount of power generated by a wind turbine depends on wind speed, and generally the higher above ground, the faster the wind. That is why modern on-grid turbines are built with towers that are 75 to 100 metres in height. And the longer the rotor blades of a wind turbine, the more wind power it harnesses – another reason why turbines are high up. To capture more wind safely at greater heights, wind turbines are designed to be big and weather resistant, for several decades.

The Gosfield-Comber project turbine layout has been developed based on the preferences of landowners, the location of homes and roads, the presence of wetlands and other sensitive natural habitats, topography, optimal clustering and spacing between turbines, scenic view sheds, and many other factors. Setback distances from houses will be imposed to respect strict sound restrictions established by Ontario's Ministry of the Environment. Also, the Town of Lakeshore has established wind farm zoning regulations with the following minimum setbacks: 600 metres from any residential or institutional zone, 450 m from any industrial or commercial zone, 300 m from an off-site residential dwelling, and the greater of 1.25 times the height of the turbine or 250 m from an on-site residential dwelling. Brookfield Renewable Power will attempt to mitigate significant, negative visual impacts from important viewpoints that are raised, before construction, to the extent possible.

Research indicates that shadow flicker can be a nuisance but is not a health issue. And it can be alleviated with proper setbacks and planting trees.

A shadow flicker simulation analysis was undertaken for the Gosfield-Comber project by AWS Truewind. Results indicated that 5 receptors within the project study area would be exposed to shadow flicker equal to or greater than 30 hours per calendar year (a prominent standard in use throughout the world). Additional study of these receptors will be conducted, and if necessary, mitigation measures will be developed (such as evergreen screens/buffers or operational curtailment).

Transport Canada imposes aviation warning lights, and has developed new standards for wind turbines. It is anticipated that at most 79 of the 149 Gosfield-Comber turbines will require medium intensity, red, fading on and off beacons.

The safety of the general public and employees are the highest priority for Brookfield Renewable Power.

During the construction period, Brookfield Renewable Power and its contractors will implement road and construction site safety policies, plans, programs, procedures and measures.

Once constructed, modern wind turbines are so safe that they operate in both densely populated and rural settings. In over 25 years, with 85,000 turbines operating worldwide, relatively few deaths have been reported. Critical turbine components will be equipped with protection systems to allow safe and proper shutdown of equipment if needed, and control will be implemented for fail safe action in the event of electrical or instrument losses. For safety reasons, generally two-person teams will conduct required maintenance, using built-in safety measures and standard procedures.

The Gosfield-Comber turbines are designed to withstand wind speeds of up to 215 km/hr – equivalent to a Level F2 tornado or Category 3 hurricane, and at wind speeds over 87 km/hr, the turbines shut themselves down through blade pitch controls and shaft brakes.

Modern turbines are programmed to shut down when too much ice builds up on their blades, and maintenance workers examine the ice conditions before starting the turbines up again.

When ice melts off of blades, it typically falls within a circular area downwind that is less than twice the rotor blade-swept area, which will not be problematic with typical sound setbacks.

The Gosfield-Comber project will have sufficient setbacks from sensitive residential and institutional land uses to provide safety from falling ice.

Interference of this sort is rarely a problem. To mitigate the impact of sound, turbines will have to be positioned a minimum distance away from residences and a minimum distance from residential areas. Any interference that does occur can be easily resolved by improving a receiver's antenna or installing relays to transmit signals around wind farms.