Monday, November 24, 2008

The 2000W challenge

the energy use each of us must stick to if we’re to keep the planet hospitable: precisely 2,000 watts.

Well I just looked at our fuel bills. The max monthly electricity bill I can find is 440kWh (December) and the min is 142 in May (neither heating nor air-con). The summer air-con peak is about 300 and the monthly ave is comfortably below this but I will round it up a little to 10kWh per day - this is for two people and covers the vast majority of our domestic fuel use since gas is just for hot water and cooking.

The cited article (which has some silliness like conflating max rated power with actual energy usage) says that domestic energy, food, and travel make up roughly 1/3 of the total each. So by that reckoning we are using about 1/3 of the suggested max for domestic energy. Our Japanese diet is certainly lower in energy demand than a typical Western diet, being rather low in meat (and calories!). We even cycle to work most days and don't own a car. But we probably make up for it with ~2 long-haul air trips per year...

8 comments:

Yoram Gat said...

If I got my numbers right that semi-annual trip home is about 1500w.

24,000 miles per year
2 MJ per passenger-air-mile
30 MSec per year

Also, note that, at least in the US, domestic consumption and transportation make only about half the total energy consumption (the rest being industrial and commercial). Even that doesn't take into account the energy consumption of net imports, which is very positive for most high-income countries.

Yoram Gat said...

One more point that occurred to me: the losses involved in electricity production are 60-70%, thus any energy consumed in the form of electricity has to be multiplied by a factor of 3.

James Annan said...

Yoram,

Thanks for the numbers. My trips are not usually "home" but rather work-related (I think I've had 1 purely holiday trip in the 8 years I've been here, although another is coming up shortly). But that doesn't help meet the 2000W limit which is supposed to be for the entire total including both work and domestic life. That would require a significant reorganisation of the way that we (scientists, or perhaps more specifically climate scientists) work.

Yoram Gat said...

> That would require a significant reorganisation of the way that we (scientists, or perhaps more specifically climate scientists) work.

Some academics have other ideas. I was commenting under the name "Sortition".

James Annan said...

I think you are right that climate indulgences are little more than a fig-leaf. If only I could hire an IvanAnywhere, or just use videoconferencing technology, it would certainly be an attractive alternative to spending 2 days on planes and two weeks with jetlag.

(Incidentally, as an addendum to my original post, the latest gas bill is not quite as insignificant as I had thought, but still only about half as much as the electricity.)

Yoram Gat said...

> I think you are right that climate indulgences are little more than a fig-leaf.

I found myself under heaps of scorn when I expressed such ideas on Deltoid (1, 2, 3, 4).

> Incidentally, as an addendum to my original post...

So what do you figure is your overall consumption? I should get around to making such an account for my household as well.

By the way - George Monbiot thinks the GW situation is getting desperate. What do you think?

James Annan said...

Well, although I tend to agree with what he writes in the actual posts, Deltoid has a lot of rather radical acolytes for my taste. Of course the blogosphere promotes such polarisation.

Monbiot is a bit of a demagogue. Stoat basically gets it right IMO (eg here, including additions in the comments). Talk of "runaway climate change" is pretty meaningless scare-mongering. We are not all going to die, at least not as a result of some climate catastrophe.

Dunno about my total - clearly flying would seem to be the biggest single factor, and also the easiest to change substantially. Food works out at 115W for a direct energy calculation based on 2500Cal daily food energy but that does not account for the underlying inputs of farming and processing, which will be significantly higher for many foods. I would hope that 5x is a generous estimate considering the lowish (by western standards) meat consumption here (I've seen estimates as high as 10x for the USA). I could eat even less meat but might then be tempted to fly overseas more!

Yoram Gat said...

> Well, although I tend to agree with what he writes in the actual posts, Deltoid has a lot of rather radical acolytes for my taste.

Yes - Lambert himself is much more reasoned than the commenters. Although in the post linked at #1 above, he does lapse into uncharacteristic faith-based reasoning.

> Of course the blogosphere promotes such polarisation.

I wonder if that is true - I am not so sure. Even on Deltoid shades of gray (or as you would say "shades of grey") can be detected. There was some discussion of this matter here.

> Food works out at 115W for a direct energy calculation based on 2500Cal daily food energy but that does not account for the underlying inputs of farming and processing, which will be significantly higher for many foods.

The energy actually stored in the food is presumably solar and therefore doesn't count. It is only the input energy (fertilizers, farm machinary, processing, transport) that is of concern - unfortunately (and to some extent amazingly), as you say, that is usually much more than the energy in the food. If we could digest petroleum that would be environmentally beneficial.

There is a book with some interesting quantitative estimates on these matters: The Consumer's Guide to Effective Environmental Choices.

> Monbiot...

I don't see him as a demagogue. That implies being manipulative. He may be wrong but I don't believe that he is manipulative. Stoat was addressing the policy matter - what can be realistically expected to be done. I was more interested in the science: are claims about positive feedback and tipping points false? Even if the Earth is never going to turn into Venus, what about smaller scale effects - couldn't these push us a few degrees higher once, say, +3C is achieved? What about, for example, the carbon released by the melting permafrost? Or the albedo change caused by the melting ice in the Arctic cap?