News, Outdoor

Cities juggle heritage and sustainability to preserve historic gas lights

At a time when municipal authorities are intent on converting their streetlighting to low-energy sources, it may come as a surprise that major cities like Berlin and London are preserving historic gas lights.

City authorities are having to strike a balance between sustainability and the passion felt by residents about their heritage.

Berlin has some 38,000 gas lights of various models still in operation. The decision to protect some of the city’s gas lights was enshrined in the founding agreement of the city’s current coalition government. The council has confirmed that all gas fittings in Berlin’s conservation areas will be preserved. So while thousands of lanterns are being retrofitted with LED sources or replaced with CFL post-top fittings, about 3,500 lanterns in conservation areas will be kept just as they are.

Areas that will still be lit by gas include parts of the city’s modernist housing estates, the old town of Spandau, and the banks of the Lietzensee lake. ‘These areas are accorded a special preservation status because of their architectural and historical significance,’ the council explains. The lanterns that survive ‘will reflect the former diversity of historical types and models of light’.

London, like Berlin, is under pressure to cut its energy costs and carbon emissions. Most of the city’s gas lights have been converted to electricity, but about 1,100 are still burning in the central boroughs and royal parks. In Westminster, for example, the 304 remaining gas lights have been designated ‘cherished assets’.

Many heritage lanterns in the borough have had LED retrofits, but the fact is that LEDs cannot simulate the look and feel of gas. Rebecca Hatch of WSP, which helps look after Westminster’s lighting, said: ‘The atmosphere created by gas lighting cannot be replicated – it retains a historic charm that electric lighting simply cannot match.’

The running cost of a gas lantern is several times that of a metal halide or LED equivalent, so the challenge is to optimise their performance and make them as environmentally friendly as possible. A strategy developed in 2010/11 led to Westminster’s gas lanterns getting new mantles and reflectors, time clocks and photocells, among other improvements. The next step is to find a central management system that will work with gas lighting.