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Cardiff's Approach to Smart Street Lighting Has Lessons for All

Eric Woods
Sep 18, 2018

Connected City 7

There is huge potential for smart street lighting to cut energy costs, reduce carbon emissions, and improve city services. However, making this a reality in large and complex cities involves much more than technology. It is therefore valuable to hear how one city specified, acquired, deployed, and is effectively managing its new street lighting system.

Cardiff, the capital city of Wales, is the UK’s fastest growing large city after London. It is home to a smart street lighting project that has seen more than 14,000 connected LED street lights deployed across the city’s strategic road network since February 2017. I recently had the opportunity to discuss the project with Lead Electrical Officer Chris Jones from Cardiff City Council, who headed the project team.

Engaging Citizens

The initial driver for the project was the need to achieve savings on the city’s energy bills, reinforced by a desire to cut carbon emissions. It began with an innovative testing program. The Council invited a group of leading LED manufacturers to demonstrate their products using a large-scale test bed along two city roads. The test bed allowed a real-world comparison of the products and enabled citizens, key stakeholders, and specialist groups to review the lighting quality.

Participants in the study responded using a pre-set scored questionnaire to determine their responses and preferences across several aspects including uniformity of lighting, color rendering, levels of glare, color appearance/temperature, and lamp aesthetics. The test area was also used by the project team for technical analysis of Lux levels and other lighting metrics. The evaluation informed the formal tender process, which led to Signify (previously Philips Lighting) being chosen to provide its LUMA lighting range and CityTouch's (now Interact City's) central management system (CMS). The system was installed by Centregreat, a Wales-based construction group.

An important insight from the test was a clear preference for using 3,000 Kelvin (K) LED lighting, making Cardiff the first UK city to choose this option for city-wide deployment. 3,000 K lamps provide a warmer white light with less glare, and so are generally found to be more comfortable for public spaces. They also avoid some of the concerns raised over the impact of widespread use of blue-light LEDs rated at 4,000 K or higher. Advances in lighting technology also means that 3,000 K lighting can now achieve energy efficiencies close to those of 4,000 K systems, meaning Cardiff is still able to meet its energy savings target.

Extended Benefits

The new system has already reduced the city’s annual energy bill by £800,000 ($1,045,700) and is expected to pay back the project costs within 5 years. In addition, around £130,000 (nearly $170,000) is expected to be saved annually in maintenance and management costs. As well as improved fault monitoring and maintenance operations, the CMS is providing the Council team with new levels of flexibility in managing the city’s lights. The team was even able to lower lighting levels in a bat conservation area to reduce the affects on local wildlife. Cardiff is the first UK city recognized by the International Dark-Sky Association for its efforts to reduce the impact of artificial lighting on the night sky.

Working with Signify, Cardiff is exploring how other devices can be connected to the “Sensor Ready” lanterns to progress Cardiff’s smart city ambitions in areas such as traffic and pedestrian monitoring, air quality improvements, and drain monitoring. The city has already 1,200 residential street lights in preparation for eventual upgrade to 22,000 residential lights. According to Chris Jones, the project has given Cardiff an infrastructure that will grow with its needs and provide quality light to make citizens feel safer. My next blog will look at some of the valuable insights that other cities can take from Cardiff’s experience.