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'Sustainable energy - without the hot air' is a recently published non-fiction book I've speed read/flicked through for work. David MacKay is a Cambridge physics professor, and he was aiming to cut through a lot of the crap journalistic reporting of energy related figures and provide some accurate ones which everyday people can understand. He has generously made the entire 366 pages book free to download from www.withouthotair.com.

My favourite part was his mention of the BBC's kind advice to British people to save energy by unplugging our phone chargers. MacKay says "Modern phone chargers, when left plugged in with no phone attached, use about half a watt... Obsessively switching off the phone-charger is like bailing the Titanic with a teaspoon. Do switch it off, but please be aware how tiny a gesture it is. Let me put it this way:

-All the energy saved in switching off your charger for one day is used up in one second of car-driving.

-The energy saved in switching off the charger for one year is equal to the energy in a single hot bath."

His point is that when it comes to saving energy, every little bit doesn't help. Don't imagine that switching your TV off standby is much of a gesture if you drive to work every day. If we are really serious about saving energy, people and governments need to make a much bigger effort, and the lifestyle changes which would really make a difference are slightly more inconvenient things like using public transport, avoiding plane flights and turning our thermostats down.

The book isn't as gloomy as it could be. I was quite cheered up to read that a 600km by 600km square in an area of North American desert, completely filled with concentrating solar power, would provide enough power to give 500 million people the average American's daily consumption of 250kWh/d. The roundabout in the Netherlands that had a separate cycle lane for cyclists was a good idea too, roundabouts scare me.


( 5 comments — Leave a comment )
May. 7th, 2009 10:06 pm (UTC)
It definitely sounds like a great book to help people make real changes, as well as combat a lot of the "greenwashing" that's going on. Thanks for the link!
May. 8th, 2009 03:07 am (UTC)
Hmm interesting.
I have never understood the phone charger thing. The circuit is broken, wouldn't it not use any energy? Or do the copper coils somehow create a circuit?
Well if that is the case, wouldn't ALL transformers use power when left plugged in (but not plugged into anything)? Why the silence on other transformers then? Most houses have heaps of them.

If you were in the habit of flicking the wall-switch this would be taken care of I guess.

Thanks for bringing this up.

Well every little bit does help - but every big big helps more :)

May. 8th, 2009 05:37 am (UTC)
Yeah, anything left plugged in uses electricity, whether or not it's actually being used. Another BIG problem are products that use electricity unneseccarily. Think of the clock on your microwave. Chances are you have another clock, or the clock/watch you use is more efficient. But whenever your microwave or VCR (dated reference, I know) or whatever is plugged in, it's draining power. And of course, costs you (or your landlord) money.

Thanks for the link! I'll be reading this as soon as I can =)
May. 8th, 2009 11:53 am (UTC)
No worries. The author managed to halve his electricity consumption by turning off 'vampires' such as his stereos, DVD player, cable modem, wireless router and answering machine. Presumably turning off the answering machine also stopped him getting any messages! Could be a bonus.

Table 11.4 has quite a useful list of how much power all the household gadgets use up. Laser printers are the worst, followed by the TV and computer. The clock on the microwave oven uses up 2 watts switched on. Each watt costs about one pound a year, so by switching my microwave off I save a whole £2 a year! Better than nothing though.
May. 8th, 2009 11:42 am (UTC)
I don't understand the science behind why phone chargers left on use up power either. I used to have one which had a little light, so I can see how that one would have.

The BBC article he mentions was funny because it said "the nuclear power stations will be switched off in a few years. How can we keep Britain's lights on? Here's three ways you can save energy: switch off video recorders when they're not in use; don't leave televisions on standby; and unplug your mobile phone charger when it's not in use."

In truth video recorders and mobile phone chargers use a miniscule amount of energy when not in use. The TV uses 10 watts on standby (compared to 100 watts when on), so is more worthwhile turning off. But the amount of power we use on powering gadgets is tiny compared to the power we use up on transport, heating and plane flights, so even if everyone frantically turned all their plugs off, in the bigger scheme of things it would do diddly squat. I turn my microwave and everything else off anyway though.
( 5 comments — Leave a comment )

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