APPENDIX G1 ENGINEERING REPORT CONCERNING THE EFFECT UPON NEARBY FCC LICENSED RF FACILITIES Evans Associates Montezuma II Wind Project RF Study ENGINEERING REPORT CONCERNING THE EFFECT UPON NEARBY FCC LICENSED RF FACILITIES DUE TO THE CONSTRUCTION OF A WIND ENERGY PROJECT In SOLANO COUNTY, CALIFORNIA “MONTEZUMA II WIND PROJECT” ICF Jones & Stokes August 18, 2010 By: B. Benjamin Evans, P.E. Evans Associates 210 South Main Street Thiensville, WI 53092 262-242-6000 PHONE 262-242-6045 FAX www.evansassoc.com Copyright 2010 Page 1 Evans Associates Montezuma II Wind Project RF Study ENGINEERING REPORT CONCERNING THE EFFECT UPON NEARBY FCC LICENSED RF FACILITIES DUE TO THE CONSTRUCTION OF THE MONTEZUMA II WIND ENERGY PROJECT In SOLANO COUNTY, CALIFORNIA ICF Jones & Stokes I. INTRODUCTION AND RESULTS SUMMARY This engineering report describes the results of a study and analysis to determine the locations of FCC-licensed microwave and fixed station radio frequency facilities that may be adversely impacted as a result of the construction of wind turbines in the Montezuma II wind project area in Solano County, California. This report describes impact zones and any necessary mitigation procedures, along with recommendations concerning individual wind turbine siting. All illustrations, calculations and conclusions contained in this document are subject to on-site verification1. Frequently, wind turbines located on land parcels near RF facilities can cause one or more modes of RF impact, and may require an iterative procedure to minimize adverse effects. This procedure is necessary in order to ensure that disruption of RF facilities either does not occur or, in the alternative, that mitigation procedures will be effective. The purpose of this study report is to facilitate the siting of turbines to avoid unacceptable impact to licensed RF facilities. Two turbine types (Siemens 2.3 MW and General Electric 2.5 MW) are being proposed for the Montezuma II project. Depending on which turbine model is constructed, the hub height would be either 80 or 85 meters. The blade radius would be 50.5 meters, thus the maximum total height of the turbine from ground level to the tip of the blade in the 12 o’clock position would be 135.5 meters. The wind turbine farm occupies a land parcel approximately 24 kilometers southeast of Fairfield, California. A specific turbine layout has been submitted for analysis. Therefore, this report will address potential impact to RF transmitting facilities due to the turbines as they are presently sited. 1 The databases used in creating the attached tables and maps are generally accurate, but anomalies have been known to occur. An on-site verification survey is suggested as part of the due diligence process. Copyright 2010 Page 2 Evans Associates Montezuma II Wind Project RF Study Using industry standard procedures and FCC databases, a search was conducted to determine the presence of existing microwave paths crossing the Montezuma II property, as well as other RF facilities within or adjacent to the identified area. The overall view of the turbine area showing microwave paths and land mobile stations is shown in Figure 1. Figure 1 – Overview of Turbine Area with Microwave Paths & Land Mobile Stations The FCC database search revealed several microwave links in the area, but only two of them appear to cross near where the turbines are to be located (WLL763/WLR685) and WQAP211/WQHV882). In addition, one land mobile base station near the turbine arrays has been identified. Copyright 2010 Page 3 Evans Associates Montezuma II Wind Project RF Study A detailed view of the turbine area is shown in Figure 2 below: Figure 2 – Detail of Turbine Analysis Area Figure 2 above also shows the position of WQHG573, the closest land mobile facility to the turbine group. This station is more than 1,000 meters from the nearest turbine. In the opinion of this consultant, the aggregate impact to this licensed facility would not be significant. Copyright 2010 Page 4 Evans Associates Montezuma II Wind Project RF Study Figure 3 - Microwave Path WQAP211/WQHV882 The microwave path shown above directly crosses the location of Turbine 23 and comes close to Turbine 21. However, impact to this path is not expected because the microwave beam is high above the turbines’ blade sweeps, as illustrated above. The green shaded area is an imaginary surface between the center line of the microwave beam and the ground directly below the microwave center line. Copyright 2010 Page 5 Evans Associates Montezuma II Wind Project RF Study Figure 4 - Wind Turbine 23 in relation to Microwave Path WLL763/WLR685 In Figure 4 above, it appears Turbine 23 is very close to Microwave Path WLL763/WLR685, however, the Worst Case Fresnel Zone appears to be below the blade sweep. If the transmitting and receiving antenna locations of the microwave link are correct as listed in the FCC license, the link is not expected to be affected by Turbine 23. It is recommended that the transmitting and receiving antennas of this microwave path be verified by land survey so that this finding can be confirmed. The geographic coordinates listed in the FCC license for a microwave path often is not accurate for purposes of siting turbines to avoid nearby microwave paths. Copyright 2010 Page 6 Evans Associates Montezuma II Wind Project RF Study Figure 5 - Wind Turbine 32 in relation to Microwave Path WLL763/WLR685 In Figure 5 above, it appears Turbine 32 is very close to Microwave Path WLL763/WLR685, the same link that comes near Turbine 23. However, the Worst Case Fresnel Zone appears to be below and away from the blade sweep. If the transmitting and receiving antenna locations of the microwave link are correct as listed in the FCC license, the link is not expected to be affected by Turbine 23. As mentioned previously, a land survey will confirm this finding. Copyright 2010 Page 7 Evans Associates Montezuma II Wind Project RF Study The detailed analysis in the following paragraphs examines the pertinent FCC licensed services and supports the summary given above. This analysis assumes that all licensed services have been designed and constructed according to FCC requirements and good engineering practice. If this is not the case, the impacted facility must share responsibility with the wind turbine company for the costs of any mitigation measures2. II. DETAILS OF ANALYSIS OF MICROWAVE LINKS An extensive analysis was undertaken to determine the likely effect of the new wind turbine farm upon the existing microwave paths, consisting of a Fresnel x/y axis study and a z-axis (height) evaluation (see Section I). The microwave overlay is available as shape files for the GeoPlanner™, ESRI™, or Google™ programs. Important Note: Microwave path studies are based upon third party and FCC databases that normally exhibit a high degree of accuracy and reliability. Although Evans performs due diligence to ensure that all existing microwave facilities are represented, we cannot be responsible for database errors that may lead to incomplete results. If, in spite of our diligence, such adverse situations should occur, Evans would perform an engineering analysis at no additional cost to determine how the additional facilities could be accommodated or, if wind turbine structures are already built, determine a method to re-direct the offending beam path. It is recommended that a field engineer visit the site to visually check for anomalies. For this microwave study, Worse Case Fresnel Zones (WCFZ) were calculated for each microwave path. The mid-point of a microwave path is the location where the widest (or worst case) Fresnel zone occurs. Possible geographic coordinate errors must be added to the Fresnel zone clearance numbers3. The radius R of the Worst Case Fresnel Zone, in meters, is calculated for each path using the following formula: where D is the microwave path length in kilometers and FGHz is the frequency in gigahertz. In general, the WCFZ is defined by the cylindrical area whose axis is the direct line between the microwave link endpoints and whose radius is R as calculated above. This is the zone where the siting of obstructions should be avoided. 2 For instance, some microwave paths may have insufficient ground clearances as they are presently configured. 3 Many microwave facilities were built before accurate methods were available to establish exact geographic coordinates (such as GPS). It is not unusual for database errors of up to 4 or 5 seconds to occur, which can effect the positioning of critical turbines located near Fresnel paths. Copyright 2010 Page 8 Evans Associates Montezuma II Wind Project RF Study Evans Associates has identified 32 active microwave links that intersect or are relatively close to the project area. These links are tabulated in Table 1 for reference. The microwave paths that come close to the sites of Turbines 21, 23 and 32 are shaded in yellow in Table 1. Copyright 2010 Page 9 Evans Associates Montezuma II Wind Project RF Study Call sign Xmit location Latitude Longitude Elevation Receive location Latitude Longitude Elevation WCFZ(m) KMT49 MOUNT VACA 38.39406 122.0988 829.1 LODI GAS STORAGE 38.17028 121.81 50.3 52.7 WNE0800 STATION 38.09297 121.8855 18.2 1799 37.9427 121.8852 589.8 10.8 WNE0802 CLAYTONHLCC 37.9427 121.8852 589.8 3599 38.09297 121.8855 18.2 10.9 WQFQ892 LODI GAS STORAGE 38.17028 121.81 50.3 MOUNT VACA 38.39406 122.0988 829.1 52.6 WQJL310 SUBSTATION 38.17122 121.8461 68.2 OPS CENTER 38.12577 121.8346 120.7 5.9 WQJL311 PORT CHICAGO 38.02125 121.9878 179.5 OPS