Azara Blog: Cambridge University energy consumption

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Date published: 2009/02/04

The Engineering Department at Cambridge University is sponsoring a series of lectures on the topic of Engineering for a low carbon future. The one today was mostly taken up with a presentation by Paul Hasley, the university "energy manager".

Apparently the university (excluding the colleges) consumed 102 GWh of electricity and 81 GWh of gas (and a smidgen of oil) in 2007-8. (The electricity figure for the colleges was apparently around 38 GWh of electricity.) This is increasing, not decreasing. Part of that increase is down to more buildings and more people. But it is apparently increasing even factoring that into consideration, and that wasn't explained. But it's probably down to more and more computers and more and more scientific equipment (the university, being a lot better off than it used to be, can afford better kit).

Hasley said that the EU is going to require a "Display Energy Certificate" (DEC) in each building, which is allegedly supposed to make the occupants of the building think about their energy use. Only it won't. First of all, after noticing the sign once or twice, people will just filter the image out of their visual processing. And more importantly, as David MacKay pointed out at the end, the information content of the DEC is very poor. The most significant visual feature is a group of colour arrows going from A ("good" energy use) to G ("poor" energy use). (So similar to what you get on washing machines, etc.) Only the scale is arbitrary and relatively meaningless and apparently it is only in comparison with other buildings "of a similar type". And there is a smaller blue bar indicating emissions, only it is scaled to be always the same height, with small almost unnoticeable text underneath giving the actual figure. There are a few real bits of information down at the bottom left corner (so consumption in MWh), but how many people will even notice it? And even if people notice it, does XYZ MWh mean anything to anyone. (So, for example, is 102 GWh of electricity good, bad or ugly given what the university does?)

There is one other problem with the DEC, and the way the energy figures were presented. It seems that the measure of interest is MWh per square meter of floor space. But is that a fair measure? For example, in some labs in Biochemistry the students and postdocs are stuffed in like battery hens. If the department decided to provide more space for these people then the MWh per square meter would go down (well, the space heating contribution might stay the same but the equipment contribution would decline). A far more sensible measure would be the MWh per some measure of productivity. Of course there is currently no such measure of productivity. But if some department, for example, can produce twice as many theses, patents, spin-out companies, etc., as some other department and they use the same amount of energy, then surely the first department is using energy more efficiently than the second department, independent of how much floor space they happen to occupy. Well, it's quite probable that there is a correlation between floor space and productivity, because there is a correlation between floor space and headcount, and there is a correlation between headcount and productivity, but the correlation won't be perfect by any means.

But energy per square meter seems to be the measure, so Hasley showed a graph of energy per square meter (for gas and electricity) by building. Amazingly enough, by far and away the worst building in the university for electricity consumption per square meter (by something like a factor of two) is the relatively recently constructed Plant Growth Facility which rather amazingly was touted as some kind of great triumph of environmental practise. This just goes to show it is not just how you construct a building but what you do with it that counts. (So apparently they have such a huge electricity bill because they have a zillion lamps to keep their plants under perfect daylight conditions, but they then also need air conditioning to cope with the heat that produces, etc.)

Hasley discussed a few of the other university buildings. He joked that the highest energy consumers per square meter were buildings that involved plants, then animals, then museums and libraries, and at the bottom of the pile, people. Needless to say, the academic middle class spend most of their time worrying about the people.

It's not clear how the university might try and reduce its energy consumption, but Hasley mentioned there would be the "soft" approach (incentives, propaganda, etc.) and the "hard" approach (upgrading existing building fabric, etc.). Hasley said that the university had managed to reduce its water consumption by a factor of three between 1987/8 and 2007/8, mostly due to scientific equipment using water more sensibly.

Apparently the city council is requiring the university to produce 10% of the energy needed by any new building from "renewable" resources, whether or not that makes any sense. (But the city council is run by the Lib Dems, a party without much common sense.)

At the end some students presented some slides which just basically said that students should be concerned (who would have thought). Then David MacKay did his short demolition of the DEC.

Then the session chair talked about what he thought should be done on three fronts. For university buildings he said they should all be retrofitted to the Swedish new-build standard. Well, England is not as cold as Sweden, so this might not make sense, even ignoring the cost (which he did, but hey, he's only an engineer). For transport he wanted air travel by university staff to be reduced by 6% per annum. (Why 6%? Hey, Why a Duck?) And he wanted the university to work closely with the city council to further screw university employees who drive to work (as if the council needs encouragement on that front). For materials, he wanted all new buildings to have a 200 year minimum life guarantee and the material to be mainly wood and/or reclaimed. Well, there is evidence for and against wood being better or worse than steel and concrete for being environmentally friendly, but let that pass. But the 200 year life span guarantee is a bit of fantasy, because no building in the country has that, although of course many buildings reach that age without the guarantee. One of the problems England faces is that the housing stock is very old, so very expensive to get to modern standards. A 200 year life span is not necessarily ideal. And in England 200 year old buildings get listed, which means that the planners make it very difficult to make any changes to them, e.g. to make them more energy efficient.

Some students handed out a long questionnaire on "Sustainable Heating" at the beginning of the lecture. Now one thing you would have thought the Engineering Department would tell its students is that surveys that are not randomly sampled are meaningless. Well, even ones that are randomly sampled are usually pretty meaningless, because the questions are slanted or simplistic. In the case to hand, the audience for the lecture was obviously full of academic middle class people concerned about energy. They are hardly representative of the general public.

And as for the questions, here is a small sample:

Q1.7: To what extent are you concerned about global warming?

This is a perfect illustration of why survey questions are so dubious. So each respondent will have a different idea what each of those statements means. And even ignoring that, it is assuming that the responsdents are honest, which on this kind of question is unlikely. It is also implying that people who "actively campaign" about global warming are the "best" and in particular have made "major lifestyle changes", and that is not self-evident.

Q2.14: What aspect of heating are you most concerned about?

Well, most people are quite probably concerned about lots of these issues, and to pick out one is making the world black and white where it is not. Further, this whole issue is very complex and the question is just reducing this complexity to a soundbite.

Q3.4: District heating and under-floor heating systems are more efficient ways of delivering heat energy. Would you like to have them even if you might have to pay a higher price for the new house?

But you have to know the cost before you can answer this question sensibly. If it's 10% more then most people would probably say yes. If it's 400% more then most people would probably say no.

Really, what is the Engineering Department doing encouraging students to waste time and energy (not to mention paper) with these kinds of meaningless surveys?

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