As the Federal Communications Commission plans to further commercialize the band of radio spectrum used by utilities for safety and service, a real-world test has shown that common Wi-Fi devices operating in this band can disrupt the electric grid. Those Wi-Fi devices range from routers to laptops to cellphones.
“We are deeply concerned by these results, especially since the unlicensed devices that were tested and shown to interfere with critical utility communications are available on store shelves today,” said Brian O'Hara, senior regulatory director at NRECA.
Electric cooperatives and other utilities rely on microwave links, or wireless connections, in the 6-gigahertz band to support essential electric operations and Supervisory Control and Data Acquisition (SCADA) systems. Until now, that band has been available only to licensed users, but the FCC recently agreed to open it to unlicensed low-power indoor (LPI) Wi-Fi devices.
“Without action, serious interference will increase, threatening electric reliability and potentially triggering power shutoffs to homes and businesses,” O'Hara said.
In April, Southern Company Services, Lockard & White and the Electric Power Research Institute field tested existing commercially available, FCC-certified unlicensed LPI devices near Southern Co.'s 6-GHz fixed microwave link between Fortson and Columbus, Georgia.
They found that one LPI device can cause enough constant interference to take out the communications network that monitors the grid for “tens of hours per year” rather than the “required design level of approximately 5 minutes per year.”
“This new testing confirmed that FCC-certified unlicensed LPI devices will cause harmful interference to licensed fixed microwave systems, including those used to monitor and protect the electrical grid and for public safety operations,” the report said.
Southern Co. reported the results to the FCC on June 23.
“These sobering results underscore our call for the FCC to take swift action to halt the certification of additional unlicensed devices to protect electric co-ops and other licensed spectrum holders,” O'Hara said.
NRECA, along with the Edison Electric Institute, American Public Power Association and Utilities Technology Council, is challenging the FCC's decision to broaden unlicensed access to the 6-GHz band.