January 23, 2012 Evaluation of Prop osed NRWC Wind Farm on Lo cal Micro climate: Preliminary Review & Work Plan For: Debbie Zimmerman Chief Executive Officer Grap e Growers of Ontario P.O. Box 100 Vineland Station, ON L0R 2E0 T 905.688.0990 By: Meiring Beyers Director Michael Roth Director Klimaat Consulting & Innovation Inc. 49 Winston Cres. Guelph, ON N1E 2K1 T 519.827.9719
2 / 12 Contents Background... 3 Preliminary Review... 3 Work Plan... 7 Step 1: Establish Scenarios... 7 Step 2: Build Computer Model... 7 Step 3: Run Computer Simulations... 8 Public Meetings: Attendance with the GGO at relevant public meetings... 8 Deliverables, Fee and Schedule... 8 Benefits of Proposed Work... 9 Conclusions... 9 References... 10 Terms of Engagement... 11 Authorization... 12
3 / 12 Background The Niagara Region Wind Cooporation (NRWC) is proposing a 230MW wind farm consisting of an estimated 80 100 horizontal-axis wind turbines immediately to the south of the Beamsville Bench and Lincoln Lakeshore sub-appellations of the Niagara Peninsula. In the Project Description Report prepared by Stantec [1], as part of a general checklist of environmental impacted, under Appendix C, item 6.5, Agricultural Lands, reads: The operation of the project will not negatively affect the use of adjoining prime agricultural lands, field crop production, or livestock pasturing, all of which can occur in close proximity to the project. Some concern has been expressed by members of the Grape Growers of Ontario (GGO) that this wind farm may in fact alter the unique microclimate of the region and perhaps negatively impact the growing conditions. Specifically, the area of concern is the region bounded by Mud/Fly Road, Town of Lincoln, (Road 73) to the south, Mountain Road (Road 12), Grimsby to the west, Highway 406, St Catherines to the west and Lake Ontario to the north. This area and the location of the proposed NRWC wind farm are shown in Figure 1. This document provides both a high-level, Preliminary Review of the influence of wind turbines on local micro-climate and a Work Plan for further study, if warranted. Preliminary Review The steep topography of the Niagara Peninsula coupled with its proximity to Lake Ontario to the north, Lake Erie to the south, and to lesser extent Lake Huron to the northwest creates an unique micro-climate as described by Wiebe [2], Shaw [3]. This micro-climate can be simply characterized as either a large-scale continental, westerly wind flow when winds are moderate to strong, similar to any other location in Ontario, to a more gravity-driven lake breeze when winds are calm to light, draining towards the nearest lake at night or blowing inland at midday, establishing the uniqueness of the micro-climate. From a high-level point of view, an individual wind turbine generates power by harvesting kinetic energy from the wind. In doing so, there is a downstream loss of kinetic energy, a so-called velocity deficit, coupled with a downstream gain in turbulence, seen as an increased gustiness or swirling flow but perhaps for a shorter duration [4]. Both the decreased wind speed and increased turbulence in the wake of the turbine can have significant micro-climatic influences, decaying with distance downstream. It should be emphasized that wind turbine impacts are negligible for anything not in this downstream wake. The increase in turbulence downstream of the turbine enhances the vertical mixing of air. That is, air at high altitude mixes with air at low altitude. If there is a contrast in temperature and/or moisture at these two altitudes, this mixing can raise or lower the surface temperature and/or moisture levels. For example, on a cold, winter s night, with warm air overlying cold air, in a stable configuration, the mixing will likely result in slightly warmer air at the ground. This situation replicates to a certain extent the beneficial impact of wind machines, used to counter cold injury to grapes [5]. However, during daytime hours, the air at higher elevations is often colder, and so mixing this air
4 / 12 Figure 1: Map of study area downwards can create colder conditions at the surface. A preliminary review done here of research on such meteorological influences of wind farm arrays [6], suggests that while most local effects are felt within the wind farm boundaries, the downstream modification of vertical temperature and moisture profiles may last approximately 20 km downstream of a large wind farm array. Horizontal-axis turbines can operate only if sufficient wind is available. This cut-in speed is approximately 3 m/s (11 km/h, 6 kt) for turbines currently being considered for the project [1]. Thus for the calm and light winds that make the region unique, the turbines will be largely inoperative, behaving similar to cellular towers, providing little impact downstream. For the wind turbines to have a significant impact, the wind speed must be strong enough for the turbines to be operating and the wind direction must be from the southeast through southwest in order for the study region to be in the farm s wake. Figure 2 illustrates the frequency of the various wind directions for the entire year, along with the percentage of time the winds are calm based on the nearest meteorological station available for this review, Vineland Research Station. Typically, the wind is greater than 3 m/s approximately 60% of the time and arrives from the southwest to southeast quadrant approximately 20% of the time. Combined, only approximately 10% of the time the wind farm will have any impact on the study area (winds greater than 3 m/s and arriving from the southwest to southeast quadrant, indicated by the grey overlay in Figure 2). This analysis can further be broken down by season and time of day (see Figure 3), with very similar results, even with varying wind speeds (higher in winter) and varying wind directions (more westerly
5 / 12 Average 3.5 m/s NNW N NNE Calm 3.7% NW NE WNW W WSW ENE ESE E Beaufort Scale: 1 2 3 4 5 6 SW 9.5% SE SSW S SSE Figure 2: Wind speed and direction frequency for Vineland Research Station. The value within the grey pie indicates when the wind turbines are impacting the study area. in winter; more southwesterly at most other times). However, cold inversion conditions, as measured above and below the Niagara Escarpment [7, 5], are typically formed and maintained when wind speeds are close to or below 7 km/h (2 m/s). Therefore, at wind speeds that the wind turbines may operate and have a downstream effect, the calm cold inversion conditions may very well be dissipated. It remains uncertain whether, at these threshold wind speed conditions (between 2 m/s to 3 m/s), the windfarm downstream wake influences are significant enough to modify the cold inversion characteristics. A more detailed analysis is required to examine whether, on balance, more negative impacts are seen over positive. A Work Plan for such a detailed analysis is discussed in the following section.
6 / 12 Night Morning Afternoon Evening 4.1 m/s 2.3% 4.5 m/s 2.4% 4.6 m/s 2.1% 4.2 m/s 2.1% Winter 8.4% 9.5% 8.4% 8.2% 3.1 m/s 6.8% 3.8 m/s 2.4% 4.1 m/s 1.2% 3.3 m/s 5.2% Spring 7.6% 8.4% 8.5% 9.9% 2.4 m/s 7.8% 3.1 m/s 2.3% 3.4 m/s 1.1% 2.6 m/s 6.1% Summer 8.8% 7.6% 12% 13% 3.1 m/s 6.3% 3.7 m/s 3.2% 3.8 m/s 2.5% 3.2 m/s 4.1% Fall 10% 11% 11% 11% Figure 3: Wind speed and direction frequency for Vineland Research Center, broken down for season and time of day. The value within the grey pie indicates when the wind turbines are impacting the study area.