Lower RF than your microwave: San Antonio smart meter findings in line with national research

The nation’s electric power infrastructure — the grid — is now more than a half a century old in most places. It’s no surprise, then, that this infrastructure is now undergoing major upgrades to keep up with our nation’s ever-rising demand for power.

The main way companies are doing this is by upgrading the grid with communication technologies allowing it to function more efficiently, deliver a higher level of service more affordably, offer consumer choice and reduce negative environmental impacts.

Known as the smart grid, the basic components include a communications network that allows automated digital meters, also known as smart meters, to send information wirelessly – i.e. across a radio frequency — to energy companies.  As smart grid infrastructure continues to grow, some people have raised concerns about the safety of smart meters and the risk of radio frequency (RF) exposure from them.

The World Health Organization has concluded that no adverse health effects have been demonstrated to result from exposure to low-level radio frequency energy such as that produced by smart meters, and many studies continue to confirm those findings. The Federal Communications Commission (FCC), the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and the Institute of Electrical and Electronics Engineers (IEEE), have set limits on power densities from electronic devices.

CPS Energy, in preparation for its own smart grid upgrades, commissioned the independent, nonprofit  Electric Power Research Institute to conduct a study in San Antonio using the type, brand, and model of meters and transmitters CPS Energy will be installing. The research was conducted using continuous transmission of data (rather than intermittent, which is how the meters will actually operate) in order capture the highest possible RF emissions.

The study’s findings were consistent with many others. It found that smart meters emit lower levels of RF emissions than cell phones, microwaves and other common household devices, and that the level of exposure is far below Federal Communication Commission limits.

Herbst AMI RF Study Summary Presentation

What is RF?

Radio frequency waves are a form of electromagnetic (EM) energy and are used for a variety of purposes, but most important, they anable telecommunications. Smart meters use low-energy radio frequency waves to transmit information across distances.  They do not transmit 99.99% of the time, typically sending a few milliseconds of data in short pulses every hour.

People are exposed daily to a variety of  electromagnetic  (EM) energy sources, from natural sources such as the sun, and from outside the earth’s atmosphere, to low levels of radio frequency (RF) energy from man-made sources, mainly telecommunications and common electronic devices.

Many devices typically cause significantly greater EM energy exposure for longer periods of time than smart meters, including cordless phone base stations and microwave ovens, which are usually positioned closer to the user.

A smart meter, usually installed on the exterior of a building, emits intermittent pulses throughout the day, usually adding up to less than one minute in 24 hours.  An RF signal typically amounts to less than one-tenth of the FCC standard and is considered safe for everyday exposure.

CPS Energy’s study includes the step-by-step processes, a description of the measuring equipment used, the mathematical computations involved.  It also references similar studies.

Measurements were calculated as percentages of the  allowable level of RF emissions as determined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).  The study data was presented in a format that is usable now and in the future, as more information becomes available. The study found:

  • From  approximately one foot away from the meter itself, electromagnetic (EM) RF wave emissions were less than or equal to  30 percent of the maximum allowable limits according to the ICNIRP standards. At  approximately three feet away, the exposure is less than five percent of the maximum allowable.
  • Smart meters produce the lowest emissions in both exposure time and intensity compared to other commonly used devices such as microwave ovens, cell or wireless telephones, compact fluorescent light bulbs and wifi modems.
  • Under typical use, smart meters emit less than 10 percent of the ICNIRP maximum safe allowable EM waves while a microwave oven produces 50 percent; a wireless phone, almost 20 percent; a cell phone, close to 15 percent and a compact flourescent lightbulb, about 20 percent.

“While many existing studies show that electromagnetic (EM) exposure of smart meters is well below safety limits identified by both government and independent agencies, CPS Energy wanted to characterize the emissions from the meters it has deployed and is planning to deploy, under the operating and environmental conditions specific to CPS Energy and its service area,” said Paula Miles, head of research at CPS Energy.

“Because the processes used for the research produce repeatable and verifiable outcomes, the results of this research project effectively increase the industry’s body of knowledge and provide further support for the safety of smart meters.”

Related research:

Radio Frequency and Smart Meters — a fact sheet from the Smart Grid Consumer Collaborative

A Discussion of Smart Meters And RF Exposure Issues — A Joint Project of the EEI and AEIC Meter Committees

 Public Utility Commission of Texas Customer Facts, Smart Meter Safety

Health Impacts of Radio Frequency Exposure from Smart Meters — California Council on Science and Technology

Tracy Idell Hamilton

Tracy Idell Hamilton was part of the Corporate Communications team at CPS Energy.

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