LightLine

LightLine pilots the use of Direct Current (DC) technology in public lighting to make urban infrastructure more efficient and easier to manage. Today, most city lighting systems still operate on Alternating Current (AC), even though DC-based solutions can reduce costs, improve energy efficiency, and require less material and maintenance when designed correctly.

The project demonstrates how cities can transition to DC-based lighting systems in practice and explores the benefits this shift can bring for energy use, infrastructure management, and future smart city services.

Challenge 

Public lighting is a significant ongoing cost for cities, and modernising these systems is often complex. Even when LED fixtures are installed, they typically still operate on Alternating Current (AC), which is less efficient and does not allow the full potential of LED technology to be used. Cities are often cautious about adopting new technical solutions, especially when their long-term reliability and cost-effectiveness have not yet been proven in real urban environments.

LightLine addresses this by providing cities with a way to test DC systems safely, transparently and with real data, allowing them to assess:

• Is DC-based lighting network cheaper to build and maintain?
• Does it ensure more stable power quality and reliable operation?
• How much energy and cost savings can be expected compared to AC systems?

Solution 

The project introduces a new multi-functional protection device for DC-based street lighting systems, developed at TalTech.

Key elements of the solution:

One device instead of many individual ones

Modern lighting systems use various protection, measurement and remote-control devices in each AC feeder, which are themselves limited in length and available power. With DC, feeders can be built much longer and the developed solution can provide additional features for monitoring and operation while offering high-level protection, significantly reducing costs and simplifying maintenance.

IT system that connects the DC controller to the city’s existing lighting management system

Cities already have or are planning to develop their remote control platforms. LightLine develops a solution that can be integrated to these platforms and aims to include:

• remote switching control and configuration
• system-wide overview and monitoring
• tracking disturbances and failures in real time

Continuous data collection for system improvement

The research team gathers operational data from both pilot cities to analyze stability, efficiency and lighting quality, and to refine the solution. These inputs will be used to promote the developed technology and the DC street lighting systems in general.

Pilot cities 

The LightLine project will be implemented in Tallinn, Estonia, and Jablonec nad Nisou, Czech Republic. The project is led by the research team from the Tallinn University of Technology (TalTech) Institute of Power Engineering and Mechatronics, together with an advisor from the city of Delft, Netherlands – one of the few cities in the world that has already tested DC-based lighting systems in practice.

Expected results

The pilots aim to demonstrate whether DC lighting solutions deliver measurable benefits:

• Cost savings in construction, operation and maintenance.
• Higher efficiency and lower energy consumption.
• Improved power quality and more stable lighting performance.
• Simplified infrastructure with fewer components to install and maintain.

If the results confirm these advantages, the solution will be prepared for commercialisation as a spin-off company.

Duration of the pilot project: November 2025 – October 2028
Total budget: € 975 000 (TalTech budget)

The implementation of pilot projects is funded by the European Regional Development Fund and the Estonian Ministry of Education and Research through the project “FinEst Targa Linna tippkeskuse piloodiprogramm“.