The pilot, developed with Tallinn University of Technology (TalTech) researchers, turns lighting poles into multifunctional infrastructure. It relies on direct current (DC) rather than traditional alternating current (AC), making it simpler and more efficient to power both lights and devices.

"Wherever these services appear, they operate on direct current," said Andrei Blinov, senior researcher at TalTech's Power Electronics research group and a recipient of this year's Estonian National Research Awards.

Using AC, he added, requires costly conversions every time someone charges a scooter or switches on an LED lamp.

Modern LED street lights are inherently DC devices. In a conventional AC network, each lamp needs a separate, complex power driver to convert the current. Switching the whole system to DC would remove that step, allowing a single cable to handle lighting and extra services.

Pilot projects have shown DC lines can maintain voltage over longer distances, making networks more efficient.

While DC systems still require voltage converters, these can be simpler, smaller, and more efficient than existing solutions. That makes DC street lighting a promising platform for integrated energy systems in future cities.

Lessons from abroad

Estonia isn't the first to experiment with DC networks. The Netherlands has led the way, with low-voltage DC guidelines and pilot projects using 350 V/700 V nominal voltages.

"The Dutch NPR 9090 standard is a key factor that has made this possible, providing clear guidance for low-voltage DC installations," Blinov said.

Groups like Current/OS and the Open DC Alliance are pushing for wider, standardized adoption of DC infrastructure. Converting existing AC networks, however, is complex and carries risks.

"DC behaves differently in fault conditions and is sensitive to insulation issues and imperfect underground connections," Blinov acknowledged.

Another key difference, meanwhile, is network design.

Traditional street lighting is radial, running from point A to point B. DC systems often use ring topologies, allowing bidirectional energy flow — in other words, power can flow both ways around the loop. This means that if a cable is damaged, power can still reach streetlights and devices from the other side.

Pilot projects have shown that DC networks also maintain more stable voltage over long distances — and lower voltage drops mean cables are used more efficiently.

Some projects report up to 30 percent material savings, reducing copper use and environmental impact. The same cables can also power both lighting and higher-capacity devices like charging stations.

Central Tallinn park as a testing ground

Researchers at TalTech have long sought to test DC street lighting locally.

With support from the FinEst Center for Smart Cities, two pilot installations were greenlit this year: one in Tallinn's Lembitu Park and another in Jablonec nad Nisou, Czech Republic.

The system follows the Dutch model in voltage and architecture. Since this is a relatively new technology for both local governments and electrical contractors, Blinov said the goal is to gain practical experience with DC lighting in Estonia's local climate and conditions.

"Our broader aim is to make DC technology a reliable, competitive choice by the time cities start renovating their streetlights," the senior researcher added.

Pilot projects allow the new solution to be compared with conventional systems, collecting data on real-world performance.

The results will guide future public procurements and maintenance training, helping DC projects become a standard urban infrastructure option in the future.

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