Light work

As part of the UK government’s drive to reduce its own carbon footprint, city councils are obliged to cut their carbon emissions by 60% by 2050.

For Westminster City Council, an obvious target for emission reductions was its streetlighting infrastructure, which comprises 15,000 lights across the borough. It knew that the traditional system of switching lights on at dusk and off again at dawn was far from efficient. The council therefore sought an electronic system that could help it manage street lighting according to demand.

“We were interested in installing a system that would enable our engineers to manage lights proactively and remotely,” recalls Dave Franks, street lighting service development manager at Westminster City Council, “dimming them in areas of low need at appropriate times and increasing the intensity of light when required.”

That search led the council to Harvard Engineering, a small industrial lighting company that has developed its own system for remotely managing streetlights, named LeafNut. There are a number of components to the LeafNut system. In each streetlamp is an ‘intelligent’ power supply. Not only can be programmed, dimming and illuminating the lamp as required, it can also detect information about the lamp – for example, if the bulb is about to expire.

Information is sent to and from the streetlights using a radio signal that is broadcast from a ‘cluster controller’. This cluster controller, located within one of the streetlights, relays information to and from up to 255 other lights. “The radio signal hops between channels randomly, so it can’t be hacked into,” explains Harvard Engineering’s finance director, Martin Baum.

The controller in turn connects to web servers, hosted on cloud infrastructure from Star Internet, via the mobile phone network. LeafNut customers control their lights by accessing the system through a web browser.

To date, Westminster City Council has installed the LeafNut system in 1,500 of its streetlights. The implementation has so far focused on main roads where high visibility is required at peak times but not all night.

According to Franks, the implementation has reduced the amount of energy required to power each of those 1,500 lights by 30%. That, of course, translates to cost savings. The LeafNut system predicts the energy consumption of light based on usage. It produces this information in the form of an industry standard code, which the council’s electricity supplier uses to calculate its bill. Frank adds that there has already been a “significant reduction” in carbon emissions.

Allowing the lighting maintenance team to monitor the system remotely eases their workload. For example, the system automatically detects when lamps have blown, or are about to, so the council no longer needs to send staff on ‘night scouting missions’ to find faulty streetlights.

The LeafNut implementation is arguably an example of so-called ‘smart’ systems that use IT to make infrastructure more efficient and more agile. By Baum’s own admission it is a very simple system, albeit one that took that company six years to develop.

“Some of the biggest challenges were related to the radio communications, which were a new venture for us,” he explains. “And the database on the server side was a big undertaking. It’s based on a standard SQL database, but the database structure and how it performs were developed in-house.” Westminster now plans to roll the LeafNut system out to all of its streetlights.

Pete Swabey

Pete Swabey

Pete was Editor of Information Age and head of technology research for Vitesse Media plc from 2005 to 2013, before moving on to be Senior Editor and then Editorial Director at The Economist Intelligence...

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