Looking around in a green light...

I have just conducted an impromptu audit of the energy being used in the building I work in. It is a modern two-floor office, housing maybe 220 people. There are 469 light fittings burning between the two floors, each with 4 18w fluorescent tubes. That's about 170 watts per person. Right now – just before 2 pm on a bright Wednesday afternoon in April - 90% of them are turned on. That’s comes to about 30 kilowatts.

That excludes the 25 much more powerful lamps blazing in the foyer, which is about 8 metres by 5 and has a skylight and main windows that, like the rest of the windows, provide ample daylight for anyone. It also excludes the stairwell opposite my desk where 9 large lamps burn. The staircase is seldom used and the lights are set so high in the ceiling that it is hard to imagine that they provide any real illumination. And in any case, the sides of the stairwell consist almost entirely of floor-to-ceiling windows. I turn the lights off every day, and every morning someone turns them back on. Also, it's heated, even though no-one spends more than a few seconds a day in there, and the heat would spread in from the main building anyway.

So what is it all being used for? It’s hard to say. We all work at self-illuminating computer screens. It’s true that it is surprisingly dark in here, but perhaps that is because people have the blinds down!