MARITIME ELECTRIC Environmental Assessment

Transcription

1 Project No.: ADDENDUM MARITIME ELECTRIC Environmental Assessment O Leary to Sherbooke Transmission Line ISO 9001 Registered Company

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3 Changes or Additions The following information is provided as an addendum to, or clarification of, the environmental assessment of the O Leary to Sherbrooke Transmission Line. The proposed transmission line is designed to conduct 200 MW and will therefore have the capacity to accommodate additional wind power that is generated in Prince County. Section 1.2 now reads: To reflect the above fact the following clarifications and additions in bold should be read into the environmental assessment. 1.2 Project Overview Maritime Electric Company, Limited (MECL) is proposing to construct and operate a 138 kv transmission line from its substation in St. Anthony near O Leary to the Sherbrooke Substation near Summerside, a distance of approximately 60 km (see Figure 1.1) in Prince County in western PEI. The proposed transmission line will connect to the recently constructed 138 kv 3 phase transmission line that extends from the West Cape Wind Energy Inc. wind farm to the O Leary Substation; it will also have the capacity to accommodate another 100 MW from other wind farms that may be constructed in the future. From the O Leary Substation the new line would be routed to the Sherbrooke Substation; there is no need for new substations, switching stations or other interconnections between these locations at this time. Construction at the Sherbrooke Substation will involve the installation of additional equipment inside the existing fenced area. At the O Leary Substation construction will be limited to the removal of some of the existing equipment inside the fenced area. Section 1.3 now reads: 1.3 Project Need and Justification Phase I of the West Cape Wind Farm, which is owned and operated by Suez Renewable Energy North America, was completed in 2007; the wind farm is located some 19 km from the O Leary Substation. This first phase consisted of 11 x 1.8 megawatt (MW) wind turbines with the capacity of generating up to 20 MW. Phase II of this development is designed to increase the total generation capacity to 100 MW; the in-service target date is the fall of To accommodate this increased transmission load, a transmission line to enable later use at 138 kv was constructed from the wind farm along the highway right-of-way to the O Leary Substation. With Phase II of the West Cape Wind Farm coming on line, there is a need to increase the capacity of the transmission system between the O Leary Substation and the Sherbrooke Substation. It is therefore proposed to construct a new transmission line to connect the existing 138 kv line to the O Leary Substation to the Sherbrooke Substation. To facilitate future wind development in the area, the 138 kv transmission line will be constructed with an additional circuit capable of transmitting up to an additional 100 MW of electricity. Section now reads: Electric and Magnetic Fields As indicated in Section , the issue that is raised about EMF from overhead transmission lines is the perception that EMF exposure can increase the occurrence of certain chronic health issues. Nearly two

4 decades of study on this topic, however, have shown that the evidence suggesting that EMF exposures pose any health risk is weak. According to the National Institute of Environmental Health Sciences, the strongest evidence for health effects has been in epidemiological studies for childhood leukaemia and chronic lymphocytic leukaemia in occupationally exposed adults. While epidemiological studies are limited in their ability to demonstrate a cause and effect relationship, cause and effect relationships can be inferred from laboratory studies. The laboratory studies in this case fail to demonstrate any consistent pattern across studies, and no indication of increased leukaemia in experimental animals has been observed. Based on previous measurements and calculations undertaken by MECL, it is estimated that the EMF values associated with an energized 138 kv line will range from 37 mg (3.7 x 10-6 T) directly underneath the fully loaded (100MW) line, 14.0 mg (14.0 x 10-7 T) at 15 m. from the line and 4.6 mg (4.6 x 10-7 T) at 30.5 m. from the line. The predicted EMF values versus distance curve is shown in Figure 6.1. When the additional 138 kv circuit is put in to service future wind development, an EMF cancellation effect due to individual line configuration will reduce the EMF values. With both circuits fully loaded (200 MW), the EMF levels will range from 23.3 Mg (2.3 X 10-6 T) directly under the transmission line, 4.5 mg (0.45 X 10-6 T) at 15 meters from the line and 0.9 mg (0.1 X 10-6 T) at 30.5 meters from the line. The predicted EMF values verses the distance curves are shown on Figure 6.2. To determine the background EMF values at various residences prior to energizing a 138 kv transmission line, MECL measured EMF values at several private residences before and after the construction of a 138 kv transmission line in western Prince Edward Island. During the background testing, the technician noted that in most of the homes, residents had unplugged their appliances, computers, televisions and turned off their lights; therefore the actual background EMF exposure in these homes is most likely higher than that measured. The results of the background testing indicated that EMF readings were highest at the point where the electrical service enter the house with readings as high as 403 mg. Inside the homes readings ranged from 0.1 mg in those areas where no appliances or lights were on, to 59.6 mg next to a fish tank that was on in one of the residences. This is in keeping with the literature which shows typical EMF values for electrical devices used in the homes and workplace to be fairly high (see Table 6.2). Many of these readings, along with the background readings obtained by MECL are higher that the anticipated EMF field measurements directly below a fully energized 138 kv line. Table 6.2: EMF Data Readings for Common Appliances (mg) Appliance EMF (10 cm from source) EMF reading (30 cm from source) EMF reading (1 m from source) Blender Clothes Dryer Clothes washers <0.1 Coffee Makers <0.1 Fluorescent Desk Lamp Hair Dryers < < Television < Source: and is based on data obtained from Gauger, J.R.

5 There are no standards or regulations in Canada associated with EMF, nor are there any regulations which dictate a minimum distance between residences and transmission lines. The International Commission on Non Ionizing Radiation Protection (ICNIRP) has developed voluntary guidelines for occupational exposure to EMF, but also exposure to EMF by the general public. It is assumed that these numbers are based upon a timed exposure of an eight-hour day for the occupational exposure and a 24 hour a day exposure for the general public. These guidelines are intended to prevent effects, such as induced currents in cells or nerve stimulation, which are known to occur at high magnitudes, much higher (more than 1,000 times higher) than EMF levels found typically in occupational and residential environments. These guidelines are summarized in Table 6.3. Table 6.3: ICNIRP Guideline Summary for Exposure to EMFs ICNIRP Guidelines for EMF Exposure Exposure (60 Hz) Electric field Magnetic field Occupational 8.3 kv/m 4.2 G (4,200 mg) General Public 4.2 kv/m G (833 mg) International Commission on Non-Ionizing Radiation Protection (ICNIRP) is an organization of 15,000 scientists from 40 nations who specialize in radiation protection. Source: ICNIRP, All of the anticipated EMF values for a 138 kv line are below these guidelines. i) Boundaries Given the linear nature of the Project footprint, the physical boundaries can be defined as a linear corridor 30 m either side of the transmission line. The temporal boundaries relate to the anticipated life of the Project. ii) Pathway Analysis As discussed above and in Section , a 138 kv power line emits low frequency, long wave length nonionizing electromagnetic energy. At a frequency of 60 Hz, it is well below the levels emitted by the microwave, or the RF radiation emitted by cellular phones and radio broadcast transmitters. Epidemiological studies have failed to establish a cause and effect relationship between electromagnetic energy and health concerns. Based on the evidence there is no obvious pathway between the proposed Project and the articulated public concern with respect to EMFA. iii) Mitigative Measures No pathway has been identified. There are no federal or provincial regulations in place; Health Canada does not consider guidelines necessary because the scientific evidence is not strong enough to conclude that typical exposures cause health exposures. No mitigative measures are proposed. iv) Residual Effects In the absence of a defined pathway and scientific verification of cause and effect, there is no impact. There can therefore be no residual effects.

6 Figure 6.2: EMF Levels 138kV Double Circuit Vertical Orientation