Loading...
3. Wind Energy Issue Paper CITY OF CHANHASSEN 7700 Market Boulevard PO Box 147 Chanhassen, MN 55317 Administration Phone: 952,227,1100 Fax: 952,227,1110 Building Inspections Phone: 952,227.1180 Fax: 952,227.1190 Engineering Phone: 952,227.1160 Fax: 952,227,1170 Finance Phone: 952,227.1140 Fax: 952,227.1110 Park & Recreation Phone: 952,227.1120 Fax: 952,227,1110 Recreation Center 2310 Coulter Boulevard Phone: 952,227,1400 Fax: 952,227,1404 Planning & Natural Resources Phone: 952,227,1130 Fax: 952,227,1110 Public Works 1591 Park Road Phone: 952,227,1300 Fax: 952,227,1310 Senior Center Phone: 952,227,1125 Fax: 952,227,1110 Web Site www.ci.chanhassen.mn.us 3 - MEMORANDUM TO: Planning Commission FROM: Angie Kairies, Planner I DATE: June 16,2009 SUBJ: Wind Turbines - Residential Zoning Districts BACKGROUND Staff received a phone call several months ago requesting information regarding locating a wind turbine in a residentially-zoned district. Staff informed the homeowner that according to City Code, the minimum lot size to locate a wind turbine is two and one-half (2-112) acres and the parcel must be zoned agricultural, commercial or industrial. The current City Code pertaining to Wind Energy Conversion Systems (WECS) was originally adopted in 1980 and amended in 1986. Currently, wind turbines are permitted through a Conditional Use Permit. The parcel in which a wind turbine is located must be zoned agricultural, commercial or industrial with a minimum two and one-half acres. The ordinance also includes detailed standards for site plan, inspections, abandonment, compliance with technical codes, height limitation, setback requirements, rotor requirements, lighting protection, tower access, signage, lighting, electromagnetic interference, noise emissions, and utility company interconnection. Following this request as well as other factors, including review of sustainable alternatives, the Planning Commission directed staff to investigate the use of Wind Energy Conversion Systems (WECS) or small scale wind turbines within residential zoning districts. Staff attended seminars at the American Planning Association National Conference as well as various wind energy workshops and has compiled the following issues and findings. ANALYSIS There are two main types of wind turbines, the horizontal axis mounted on a pole or tower, and the vertical access wind turbine that can be mounted on rooftops. Chanhassen is a Community for Life - Providing for Today and Planning for Tomorrow Planning Commission Wind Energy Issue Paper June 16,2009 Page 2 Horizontal Axis 1. The engineered monopole design, which has the smallest footprint, is generally non-climbable and causes the least bird fatalities. 2. The lattice pole, which is similar to an electrical pole design, pole is easily climbable and causes some bird fatalities. 3. The guide tower is a single pole stabilized with several guide wires. This design has the largest footprint based on the extension of the guide wires. It is somewhat climbable, but this design causes the most fatalities among birds. Vertical Axis Vertical axis wind turbines can be mounted on rooftops and the spinners range from 40.5 to 155 inches in height above the base; however, they are not as prevalent as the horizontal axis turbines. If these devices are mounted on rooftops, they generally do not clear the surrounding trees and therefore are less effective. Additionally, there are building code issues with mounting them on the house due to the residual effects of the vibrations caused by the rotation of the blades causing the house to shake. Wind turbines have been in existence since the 14th century. In the past few decades the design and safety features have continued to advance making them more accessible and safe for small-scale uses. However, there are several concerns regarding small-scale wind turbines within residential zoning districts. Issue: Siting Issues Finding: The height and location of the wind turbine is dependent on the location in relation to existing structures. A wind turbine should be a minimum of25-30 feet above the tallest structure or tree to work efficiently and effectively. This would put the tower at 45- 125 feet tall depending on the surroundings. Planning Commission Wind Turbine Issue Paper June 16, 2009 Page 3 Issue: Parcel Size and Setback Requirements Finding: The suggested lot size is one and one-half acres, which excludes many of the residentially-zoned parcels within the city. The minimum lot size in the RSF district is 15,000 square feet or 0.34 acre. The current WECS ordinance requires the parcel be agriculturally zoned and a minimum two and one-half acres. The minimum lot size in the Rural Residential (RR) and the Agricultural Estate (A2) district is two and one-half acres. Setback requirement is typically a 1: 1 ratio, (height to setback) for visibility purposes as well as the perception of safety. Some of the safety concerns are a tower falling over and having enough clearance to avoid falling on a structure. The current ordinance requires the tower or pole to be engineered to avoid this problem, but is still a concern of adjacent property owners. Issue: Noise is also a concern when it comes to wind turbines within residentially zoned districts. Will it create a buzzing or disrupt the surrounding area? Finding: It is recommended that the maximum noise level be no greater than 55 decibels (50 decibels is similar to a refrigerator humming). Thirty MPH winds will exceed 55 decibels but is rare. The noise of a turbine is often drowned out by other factors such as typical traffic. The current City Code requires that noise emitted from a WECS be in compliance with state pollution control standards. Issue: Other safety concerns include blades and/or ice being thrown from the structure. Finding: In reality the possibility of blades being thrown are slim to none with an engineered turbine. Additionally, the weight of ice collection on the blades will slow down the rotation of the blades almost to a halt; therefore, throwing of ice is virtually impossible. Issue: Blade flicker is another concern with wind turbines. Blade flicker is the shadow flickering effect that is caused when the blade rotates through direct sunlight. Finding: Wind turbines can be programmed to shut down during periods of the day when this would typically occur. Conclusion The technology for wind turbines has advanced significantly for small wind devices; however, the biggest issues are still with the siting concerns. The recommended minimum parcel size and the height of the structure do not lend the use to residentially zoned districts. Planning Commission Wind Turbine Issue Paper June 16,2009 Page 4 RECOMMENDATION Staff is requesting direction on whether to continue with the current WECS city code ordinance or to gather additional information pertaining to wind turbines in residential zoning districts. ATTACHMENT 1. Chapter 20, Article XXIII, Division 6, Wind Energy Conversion Systems (WECS). g:\plan\issue paper\wind energy issue paper pc 6-16-09.doc DIVISION 6. WIND ENERGY CONVERSION SYSTEMS (WECS) Sec. 20-1041. Purpose. The purpose of this division is to establish standards and procedures by which the installation and operation of WECS shall be governed. (Ord. No. 80, Art. VI, ~ 20(6-20-1), 12-15-86) Sec.20-1042. Ornamental wind devices. Ornamental wind devices that are not a WECS shall be exempt from the provisions of this division and shall conform to other applicable provisions of this chapter. (Ord. No. 80, Art. VI, ~ 20(6-20-8), 12-15-86) Sec. 20-1043. When allowed. Wind conversion systems may be allowed as a conditional use subject to the regulations and requirements of this division, provided the property upon which the system is to be located is zoned agricultural, commercial or industrial and is constructed and maintained on any parcel of at least two and one-half acres in size. (Ord. No. 80, Art. VI, ~ 20(6-20-2), 12-15-86) Sec. 20-1044. Declaration of conditions. The planning commission may recommend and the city council may impose such conditions on the granting of WECS conditional use permit as may be necessary to carry out the purpose and provisions of this division. (Ord. No. 80, Art. VI, ~ 20(6-20-3), 12-15-86) Sec. 20-1045. Site plan. All applications for a WECS conditional use permit shall be accompanied by a detailed site plan drawn to scale and dimensioned, displaying the following information: (1) Lot lines and dimensions. (2) Location and height of all buildings, structures, above-ground utilities and trees on the lot, including both existing and proposed structures and guy wire anchors. (3) Location and height of all adjacent buildings, structures, above-ground utilities and trees located within 350 feet of the exterior boundaries of the property in question. (4) Existing and proposed setbacks of all structures located on the property in question. (5) A sketch evaluation of the premises accurately depicting the proposed WECS and its relationship to structures on adjacent lots. (Ord. No. 80, Art. VI, S 20(6-20-4), 12-15-86) Sec. 20-1046. Inspection. The city reserves the right upon issuing any WECS conditional use permit to inspect the premises on which the WECS is located. If a WECS is not maintained in operational condition and poses a potential safety hazard, the owner shall take expeditious action to correct the situation. (Ord. No. 80, Art. VI, S 20(6-20-9), 12-15-86) Sec. 20-1047. Abandonment. Any WECS or tower which is not used for six successive months shall be deemed abandoned and shall be dismantled and removed from the property at the expense of the property owner. (Ord. No. 80, Art. VI, S 20(6-20-10), 12-15-86) Sec. 20-1048. Compliance with technical codes. (a) Standard drawings of the structural components of the wind energy conversion system and support structures, including base and footings shall be provided along with engineering data and calculations to demonstrate compliance with the structural design provisions of the Minnesota State Building Code as adopted. Drawings and engineering calculations shall be certified by a registered engineer. (b) WECS electrical equipment and connection shall be designed and installed in adherence to the National Electrical Code as adopted and amended by the city. (Ord. No. 80, Art. VI, S 20(6-20-5,6-20-6), 12-15-86; Ord. No. 377, S 125,5-24-04) Cross references: Technical codes, S 7-16 et seq. Sec. 20-1049. Height. (a) The permitted maximum height of a WECS shall be determined in one of two ways. In determining the height of the WECS the total height of the system shall be included. System height shall be measured from the base of the tower to the highest possible extension of the rotor. (1) A ratio of one foot to one foot between the distance of the closest property line to the base of the WECS to the height of the system. (2) A maximum system height of 175 feet. (b) The shortest height of the two above-mentioned methods shall be used in determining the maximum allowable height of a WECS system. The height of a WECS must also comply with FAA Regulation part 77 "Objects Affecting Navigable Air Space" and/or MnDOT Rule 14, MCAR 1.3015 "Criteria for Determining Obstruction to Air Navigation. " (Ord. No. 80, Art. VI, S 20(6-20-7(1)), 12-15-86) Sec. 20-1050. Setbacks. No part of a WECS (including guy wire anchors) shall be located within or above any required front, side or rear yard setback. WECS towers shall be set back from the closest property line one foot for everyone foot of system height. WECS shall not be located within 30 feet of an aboveground utility line. (Ord. No. 80, Art. VI, S 20(6-20-7(2)), 12-15-86) Sec. 20-1051. Rotors. All WECS rotors shall not have rotor dimensions greater than 26 feet. Blade arcs created by the WECS shall have a minimum of 30 feet of clearance over any structure or tree within a 200-foot radius. Each WECS shall be equipped with both a manual and automatic braking service capable of stopping the WECS operation in high winds (40 miles per hour or greater). (Ord. No. 80, Art. VI, S 20(6-20-7(3)--(5)), 12-15-86) Sec. 20-1052. Lightning protection. Each WECS shall be grounded to protect against natural lightning strikes in conformance with the National Electrical Code as adopted and amended by the city. (Ord. No. 80, Art. VI, S 20(6-20-7(6)), 12-15-86) Cross references: Technical codes, S 7-16 et seq. Sec. 20-1053. Tower access. To prevent unauthorized climbing, WECS towers must comply with one of the following provisions: (1) Tower climbing apparatus shall not be located within 12 feet of the ground. (2) A locked anti-climb device shall be installed on the tower. (3) Tower capable of being climbed shall be enclosed by a locked, protective fence at least six feet high. (Ord. No. 80, Art. VI, S 20(6-20-7(7)), 12-15-86) Sec. 20-1054. Signs. WECS shall have one sign, not to exceed two square feet posted at the base of the tower and said sign shall contain the following information: (1) Warning high voltage. (2) Manufacturer's name. (3) Emergency phone number. (4) Emergency shutdown procedures. (Ord. No. 80, Art. VI, S 20(6-20-7(8)), 12-15-86) Sec. 20-1055. Lighting. WECS shall not have affixed or attached any lights, reflectors, flashers or any other illumination, except for illumination devices required by FAA Regulations part 77 "Objects Affecting Navigable Air Space" and FAA Advisory Circular 70/7460-1K CRGl April 15, 2000. (Ord. No. 80, Art. VI, S 20(6-20-7(9)), 12-15-86; Ord. No. 377, S 126,5-24-04) Sec. 20-1056. Electromagnetic interference. WECS shall be designed and constructed so as not to cause radio and television interference. (Ord. No. 80, Art. VI, S 20(6-26-7(10)), 12-15-86) Sec. 20-1057. Noise emissions. Noises emanating from the operation of WECS shall be in compliance with and regulated by the state pollution control standards, Minnesota Regulations NPC 1 and 2, as amended. (Ord. No. 80, Art. VI, S 20(6-20-7(11)), 12-15-86) Sec. 20-1058. Utility company interconnection. No WECS shall be interconnected with a local electrical utility company until the utility company has reviewed and commented upon it. The interconnection of the WECS with the utility company shall adhere to the National Electrical Code as adopted and amended by the city. (Ord. No. 80, Art. VI, S 20(6-20-7(12)), 12-15-86) Cross references: Technical codes S 7-16 et seq.