How to make street lighting more efficient

One of the main expenditures of municipalities is to cover lighting and the operation of outdoor lighting. We are all familiar with it: an overabundance of streetlamps that are also lit unnecessarily and traditional light bulbs that are not very sustainable. We all strive to be greener in our homes and workplaces, but what about on the streets?

According to data from the European Energy Efficiency Platform, street lighting can account for 30-50% of total municipal electricity consumption in Europe. It is crucial that it is efficient and sustainable. At the national level, according to data provided by Ángel Sánchez de Vera, head of Services and Agriculture in IDEA's Energy Saving and Efficiency Directorate, municipal outdoor lighting is made up of some 8.8 million light points with an average power of 156 W/PL. This means an estimated electricity consumption of 5,296 GWh in one year, at a cost of 741 million euros.

The keys to more efficient and sustainable street lighting

In view of these figures, numerous efforts are being made by public institutions and private companies to reduce the environmental and economic impact of public lighting without losing safety for citizens.

This process is based on a transformation from traditional technologies to more efficient ones and the search for more sustainable energy sources:

LED technology

One of the first steps must undoubtedly be to opt for LED technology, which has revolutionised the lighting market thanks to its low energy consumption. In fact, it has been proven that it can reduce the installed power by an average of 60-80% without reducing lighting levels. For this reason, Ángel Sánchez de Vera, head of services and agriculture in the IDAE's Directorate for Energy Saving and Efficiency, insists on the "replacement of light points in outdoor lighting and the lighting of pedestrian, artistic or monumental spaces with LED technology.

The data provided by Enrique Larrosa of Signify Spain and Portugal is very enlightening: "In a city of 40,000 inhabitants, by changing all streetlights to LEDs, we could save €1,240,000 per year, reduce CO2 emissions by 2,000 tonnes (equivalent to 95,000 trees) and free up the electricity grid to use this energy for other purposes, such as charging 2,000 electric vehicles per year or 30,700 electric bicycles".

In Europe, an increasing number of cities are using this technology. Back in 2012, the city of Mechelen in Belgium was a pioneer by replacing all its traditional lighting with LED lighting. Three years later, in Hungary's Balatonfüred, with a population of 13,500 people, they opted for LED technology and installed 1,400 GE luminaires. These towns and cities are joined by many others in the Netherlands, Belgium, France, the United Kingdom, Norway and Estonia.

Sensors and luminous flux regulation

Another step should be to implement systems that regulate light flow and the switching on and off of streetlights. Not all areas of the same municipality have the same street lighting needs at all times, so the aim must be to ensure that they vary and adapt throughout the night to the needs of the citizens. This would reduce consumption and also minimise light pollution.

Linked to this renewal is digitisation and the collection and study of data. This is a crucial implementation for the technical teams in charge of preventing and resolving incidents and general lighting maintenance. This data is collected by sensors and cameras in the lighting infrastructure to monitor aspects such as traffic volume or air quality. The study and analysis of this data allow better energy use by providing information on occupancy, noise or temperature.

After data analysis, which would not be possible without digitisation, this work is reduced to several practical measures. For example, the Norwegian company Comlight offers motion sensor lighting control systems that dim lamps by up to 20% when there is no traffic. This keeps the lighting inviting users to use the path, but saves on electricity and reduces light pollution. Of course, as soon as traffic is detected, the lighting returns to full illumination.

The Italian cities of Rome, Piacenza and Rimini are already using systems to adapt consumption to the needs of the moment with the LIFE-DIADE-ME programme financed by the European Commission. Sensor networks have enabled adaptive lighting that changes according to nearby traffic, surrounding lighting and weather conditions to save energy, reduce emissions and improve safety. As a result, CO2 emissions have been reduced by 41% compared to the previous technology.

Solar panels

In addition to efficiency, achieving environmental objectives requires a focus on sustainability. To this end, solar panels in public lighting are an option that more and more municipalities are choosing to go for sustainability and reduce emissions in their municipalities. Today, there is a wide range of products on offer, from small and specific area lighting to larger areas, systems with or without columns, with motion detectors or static.

The process is very simple: a solar panel collects the light rays during the day and stores them in a battery system to distribute the accumulated energy at night to illuminate energy-saving LED screens. Some of its uses are: illuminated zebra crossings at night, streetlights, traffic lights, and parking meters.

Efficient public lighting in Spain

Traditionally, the figures for Spain have not given cause for much optimism. For example, in 2011, our energy consumption for street lighting was the highest in Europe, three times higher than in other countries such as Germany, with far fewer hours of sunlight: 115kWh per inhabitant per year, compared to 45kWh in Germany, according to the study on Light Pollution by the Complutense University of Madrid. Ten years later, the figures had not improved much: we were in third place, behind Malta and Portugal.

Therefore, in October 2022, the Council of Ministers approved a Royal Decree Law introducing measures to improve the public lighting system and increase energy efficiency. In this respect, many Spanish cities are already implementing changes to become more sustainable.

For example, in Mérida, Badajoz, with the collaboration of Endesa X, they changed 7,000 of the total 15,817 lighting points to LED technology, as well as installing this type of lighting on Guadiana Island and 205 lighting remote control systems. The case is similar in Sarrià de Ter, Catalonia, where 1,085 light points were converted to LED technology out of a total of 1,355. Twenty-two remote control systems for lighting have also been installed.