Agenda - 05-27-2014 - C1 - Laserfiche WebLink

Browse Search

Electric and Magnetic Fields (EMF) 25 Question- What, if any, health risks do the electric and magnetic fields (EMF) from solar panels and other components of solar PV arrays pose? Bottom Line- Electric and magnetic fields are a normal part of life in the modern world PV arrays generate EMF in the same extremely low frequency (ELF) range as electrical appliances and wiring found in most homes and buildings The average daily background exposure to magnetic fields is estimated to be around one mG (milligauss — the unit used to measure magnetic field strength), but can vary considerably depending on a person's exposure to EMF from household electrical devices and wiring The lowest exposure level that has been potentially associated with a health effect is three mG. Measurements at three commercial PV arrays in Massachusetts demonstrated that their contributions to off -site EMF exposures were low (less than 0 5 mG at the site boundary), which is consistent with the drop off of EMF strength based on distance from the source More Information. Solar PV panels, inverters and other components that make up solar PV arrays produce extremely low frequency EMF when generating and transmitting electricity. The extremely low frequency EMF from PV arrays is the same as the EMF people are exposed to from household electrical appliances, wiring in buildings, and power transmission lines (all at the power frequency of 60 hertz) EMF produced by cell phones, radios and microwaves is at much higher frequencies (30,000 hertz and above) Electric fields are present when a device is connected to a power source, and are shielded or blocked by common materials, resulting in low potential for exposure On the other hand, magnetic fields, which are only generated when a device is turned on, are not easily shielded and pass through most objects, resulting in greater potential for exposure Both types of fields are strongest at the source and their strength decreases rapidly as the distance from the source increases For example, the magnetic field from a vacuum cleaner six inches away from the motor is 300 mG and decreases to two mG three feet away People are exposed to EMF during normal use of electricity and exposure varies greatly over time, depending on the distance to various household appliances and the length of time they are on The daily average background level of magnetic fields for U S residents is one mG EMF from PV Arrays- Solar PV panels produce low levels of extremely low frequency EMF, with measured field strengths of less than one mG three inches from the panel Solar PV power inverters, transformers and conduits generate higher levels of ELF -EMF The amount of ELF -EMF is proportional to the electrical capacity of the inverter and is greater when more current (electricity) is flowing through a power line In a study of two PV arrays (using 10 -20kW invertors) in Kerman and Davis, California, the magnetic field was highest at the inverters and transformers, but decreased rapidly to less than one mG within 50 feet of the units, well within the boundary of the PV array (Chang and Jennings 1994) This data indicates that extremely low frequency EMF field strengths at residences near systems of this size would be below the typical levels experienced by most people at home The highest extremely low frequency EMF (up to 1,050 mG) was found next to an inverter unit at the point of entry to the electrical conduits Even this 10