Lighting special Street illumination >
case up and investigating the different systems.’ Westminster will be installing Harvard Engineering’s
Leafnut system. With 1,500 luminaires already upgraded, the Smart Light programme involves just under 16,000 street lights and a four-year timescale. ‘Energy saving is a massive driver at the moment
because of things like the Carbon Reduction Commitment [Energy Effi ciency Scheme],’ says Franks. ‘Switching every third column off is not an option. You need to be able to demonstrate decent energy management. This is what we’re trying to achieve with our Smart Light project using CMS so we can increase and decrease light levels when required. ‘For the outside of theatres and stations, for instance,
Energy
costs Around one third of Europe’s roads and motorways are still lit using cheap, ineffi cient 1960s technology, namely mercury vapour lamps (an estimated 35m) which use twice the electricity necessary. Some countries
(UK, Belgium, the Netherlands, Poland) use less than others (Germany, Italy, Spain) and, along with the Netherlands, the UK is a leader in white lighting. City councils
could save €3 billion (based on 2006 energy prices) in energy costs per year by switching to the latest roadlighting technology, such as ceramic metal halide lamps (non-retrofi t). This equates to: • 10m tonnes of CO2 • 45m barrels of oil per year
• Annual output of 15 power stations at 2TWh/yr
you might generally run fi ttings at CE1 [the EN131201 category for 30 minimum maintained lux] but you can go up to CE0 [50 lux] and down to CE2 [20 lux]. It’s about having that fl exibility. If you’ve decided your worst-case scenario is CE0, you’d be overlighting for quite a bit of the time and using more energy than you need to. It’s about understanding the environment you’re designing for and a fi t-for-purpose rather than broad brush approach.’ A further refi nement that Westminster is working
on with Harvard will allow the police to change street lighting levels using CMS – raising them when chasing a criminal in a particular location perhaps. It’s just one indicator of the increased role that the humble street light may play in the future.
Masterplan At the ILP conference in September, Mark Sutton- Vane of independent lighting consultant Sutton Vane Associates (SVA), called for a lighting masterplan for the UK that would radically rethink the way we light the public domain in particular. It ranges in scope from closer working between lighting designers and engineers, to using the tax system to encourage energy effi ciencies and freeing lighting designers from legislation that often lags behind advances in lighting technology and techniques. ‘There’s no doubt that street lighting will have to do
more in future,’ says Sutton-Vane. ‘We don’t have to look too far ahead, for instance, to envisage a time when standard street lighting links into the Smart Grid, so that a street lamp could also operate as a charging point for electric cars and bikes, and may even incorporate some form of microgeneration.’ Some street lighting is already multitasking, he
adds. SVA was recently involved in lighting Letchworth Garden City’s centre. The lighting is intended to help encourage a night-time economy to develop and restore Letchworth as a destination. It includes specially designed lighting columns supporting lanterns that can be dimmed remotely, but also contain controls for CCTV and traffi c signals. To save energy, astronomical clocks are used to control not only the architectural lighting in the centre, but also the highway lighting, which dims automatically between midnight and sunrise. The one technology that hasn’t yet made it onto the
42 CIBSE Journal November 2010
Town centre lighting design is at the heart of Letchworth Garden City’s£8m revitalisation programme
streets in any signifi cant way is the LED, despite the fact that all the leading street lighting manufacturers are lining up their contenders. They are the obvious light source of the future, for the exterior as much as the interior – energy effi ciency, longevity, reduction of maintenance costs, dimmability, viability with solar/ wind-powered luminaires – all potentially give the LED massive advantages over traditional sources. They could also cheer up town centres on the decorative front – Westminster is looking into integrating colour- changing RGB LEDs into lanterns for use for special events. But as a white light source, cost and inferior performance over existing counterparts mean they don’t add up to a viable solution just yet. ‘At the moment it doesn’t make sense to use LEDs rather than CosmoPolis,’ says Scott. ‘Cosmo is more effi cient at getting light on the ground and is more of a known quantity. There’s not much difference in energy consumption and it’s cheaper.’ Franks agrees: ‘There is a glare issue and the colour
temperature is not right for us: they’re still coming in at 4,000K plus, which is too cold. We’re starting to see viable lanterns but they cost a fortune. The costings just don’t stack up.’ We might not be seeing the Light Blossom on
our streets any time soon, but the future is bright. ‘Street lighting will be much improved,’ says Scott. ‘The competence of lighting designers is improving, the quality of sources is improving dramatically with a lot more white light, and there’s less overlighting. All of those things are pushing street lighting in the right direction.’ ●
The Society of Light and Lighting is holding a free event, Future Trends in Street Lighting, on 14 December 2010 at the Transport Museum, London. It starts at 6pm. To fi nd out more and to register, visit
www.sll.org.uk
www.cibsejournal.com
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