PowerSwitch

wired.co.uk - 26/02/10



Penny pinching and energy saving are both extremely fashionable at the moment, and when the two areas collide you can be sure there'll be some political reaction, which is why street lighting has come under government review recently.

According to the British Astronomical Association, each street lamp in the UK emits a total of 0.33 of a gigawatt of wasted light per year -- that's light which filters above the level of the horizon rather than towards the street. Rough back of the fag packet calculations -- pricing electricity at a fairly reasonable, albeit domestic 10.5p per kilowatt -- makes that nearly £35 pounds per year per light, which is why the Sustainable City Lights from Philips are such an intriguing concept.

These unusual looking bits of street furniture will apparently adapt to the environment as they mimic the behaviour of a flower by opening and closing to gather energy. By collecting energy from the sun and wind, the Sustainable City Lights are self powering, but also possess the ability to give back to the grid if it overproduces to help feed other items draining power. They're also far more energy efficient than regular lights as they use LEDs.

More importantly, however, they have the intelligence to turn down the wick when they are not needed, thanks to proximity sensors that will only activate when a person comes suitably close to require the lighting. This not only makes them more energy efficient, but also reduces light pollution -- something the BAA will no doubt strongly approve of.

For the moment they are only concepts. But with saving the planet high on every political agenda, it might not be too long before these solar panelled, wind turbine street lamps become a reality, banishing the blinking orange street light for good.

Original Article

According to the British Astronomical Association, each street lamp in the UK emits a total of 0.33 of a gigawatt of wasted light per year...

And according to me the British Astronomical Association (or more likely Wired) are energy illiterate. What is a gigawatt per year?

If you mean 0.33 gigawatt hours per year that's ridiculous, equivalent to wasting 37kW 24/7 per lamp! If they mean total waste over all street lamps that ridiculously low...

£35 at 10.5p per kilowatt buys 333 kWh. So the correct answer could be 0.33 megawatt hours. Not megawats per year!

However checking the linked House of Commons publication it says "...from street lights amounts to 0.33 of a gigawatt a year." No mention of individual street lamps.


I now expect your £35 per lamp calculation is complete red herring, and the the truth is waste of 0.33 GW, which totals 2.9 TWh per year at a cost of ~£303 million (your 10.5 p/kWh).

Come on Wired, sort it out!