Getting electricity to every home and business was one of the last century’s great infrastructure challenges in many parts of the world. AT&T says that the electrical grid can help solve this century’s challenge of making high-speed Internet universally available.

A new project unveiled today, called AirGig, uses power lines to guide high-speed wireless data signals over long distances, upgrading electrical infrastructure to double as Internet infrastructure. AT&T has been testing the technology by linking up its office buildings and is searching for a community to host a public test next year.

John Donovan, AT&T’s chief strategy officer, said Tuesday that piggybacking on power lines makes AirGig much cheaper than laying traditional data cables or installing the towers and antennas of conventional wireless infrastructure. That means AirGig could transform broadband availability in rural areas, whether in the U.S. or overseas, he said.

In the U.S., people in rural areas and with lower incomes are much less likely to have access to broadband (see “The Next President Will Inherit America’s Embarrassing Digital Divide”). Infrastructure costs are a major reason more than half the world’s population is without broadband access.

AirGig involves mounting small plastic antennas on power lines so that they can draw power from them wirelessly and shoot wireless signals through the air. Those signals don’t travel inside the cables but are tuned to use them like guard rails. Each link can carry multiple gigabits of data, according to AT&T. An AirGig system would use conventional cellular or Wi-Fi antennas to offer connectivity to people and their devices.

Because it doesn’t send data signals through the electricity cables themselves, AT&T says, its system can avoid the cost and reliability problems that plagued earlier schemes to transmit broadband over power lines. The company says it is open to both using AirGig on its own network and offering it to other companies.

AT&T’s cable-hugging wireless connections use millimeter-wave signals with higher frequencies than Wi-Fi or cellular connections. The company joins others betting that millimeter-wave wireless can slash the costs of Internet infrastructure.

Google Fiber, the search giant’s project aimed at shaking up U.S. broadband, has launched fiber-optic networks in several U.S. cities but is pivoting to focus on the same wireless technology (see “Google Fiber Stalls and the Industry Gears Up for Ultrafast Wireless”). Millimeter-wave signals also underpin a wireless broadband project launched by Facebook this year (see “Facebook is Testing a Super-Speed Public Wi-Fi System”).