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Understanding Radio Frequency

“Wireless smart meters, when installed and properly maintained, result in much smaller levels of radio frequency (RF) exposure than many existing common household electronic devices, particularly cell phones and microwave ovens.”

“Health Impacts of Radio Frequency from Smart Meters.” Published April 2011 by California Council on Science and Technology

We understand that our customers want to be well informed about new technologies, how the smart grid works and how it will change their relationship with the energy they use. Smart meters are one of the most visible components of the smart grid. They are digital meters that contain the ability to communicate with the utility via a two-way network. Smart meters transmit for only a fraction of the day for short durations and actual radio frequency (RF) emissions are actually less than commonly used devices, such as cell phones, baby monitors and microwave ovens.

Silver Spring-enabled smart grid devices not only meet the Federal Communications Commission (FCC) rules, but in actual usage, transmit significantly less frequently.

Comparison of RF Power Density in the Everyday Environment


Source
   RF Output Compared to Standing
Two Feet From a Smart Meter
Standing in front of an active microwave oven, two feet from the door   550 times more
Holding a walkie-talkie to your head   55 – 4,600 times more
Holding an active cell phone to your head   3.3 – 1,100 times more
Using a laptop computer   1.1 – 2.2 times more
Sitting in a Wi-Fi cyber café   1.1 – 2.2 times more

Source: Health Impacts of Radio Frequency from Smart Meters by California Council on Science and Technology, April 2011

Silver Spring Networks continually monitors regulatory and scientific developments related to human exposure to RF emissions. Silver Spring Networks relies on expert scientific conclusions related to RF exposures and potential health effects. According to the FCC, the Electric Power Research Institute (EPRI) and the California Council on Science and Technology (CCST), no adverse short or long-term health effects have been shown to occur from the radio frequency signals produced by smart meters or other such wireless networks.

In April 2011, the California Council on Science and Technology (CCST) released a preliminary study entitled "Health Impacts of Radio Frequency from Smart Meters".

Quoting from the study, there are two primary conclusions:

  • The FCC standard provides a currently accepted factor of safety against known thermally induced health impacts of smart meters and other electronic devices in the same range of RF emissions. Exposure levels from smart meters are well below the thresholds for such effects.
  • There is no evidence that additional standards are needed to protect the public from smart meters.
Exposure of individuals in their smart-meter equipped homes is commonly orders of magnitude less than that which would occur for an individual standing immediately adjacent to and in front of the meter. In measurements performed in six California residences, 99% of the measured peak values were less than 0.8% of the MPE with 90% of the measured values being less than 0.1% of the exposure limit.

Electric Power Research Institute
December 9, 2011

Smart Meter Devices and the FCC Limits

Based on years of studying whether radio waves cause health effects, the FCC has adopted Maximum Permissible Exposure (MPE) limits for radio transmitters of all types, including smart meters. It includes a prudent margin of safety just in case some health effects are too subtle to have been detected. Even so, smart meters operate far below the limit—typically only about one-seventieth as much.

Exposure is based on the transmitter's power and your distance from the source. In general, doubling your distance cuts the "power density" by a factor of four. That's a major reason why radio waves from a smart meter, at a distance of 10 feet, are only about one one-thousandth as much as a typical cell phone. That's also why powerful but distant radio and TV transmitters are not seen as posing any danger.

Additional Resources

British Medical Journal

California Council on Science and Technology

Demand Response and Smart Grid Coalition

Electric Power Research Institute

EMC Technologies Prepared for Department of Primary Industries, Victoria, Australia

Federal Communications Commission

Silver Spring Networks

Utilities Telecom Council

World Health Organization