Monday, 26 June 2017

Climate change in Cambridge

We know global temperatures have been increasing - it is happening here in England too. Here are some charts based on MET office monthly average data since 1910 [1]. The clearest changes are in minimum temperature. I see no trends in rainfall, which surprised me.

These are for East Anglia (which includes Cambridge where I live). The blue lines are the 10 year running average. The first chart is for August. There is considerable variation even in the running average and the increase is not linear but is more marked since about 1995.
(max - min) for the running 10 year mean is 2.1C. In my lifetime the change is 1.3C.

Friday, 23 June 2017

More energy label confusion coming

Under the EU energy label scheme appliances were originally labelled A-G with A as the best. Then as standards improved new grades were introduced: A+, A++ and for some products we now have A+++; apparently this is confusing. So the EU is updating the scheme with a rescaling so everything goes back to A-G: they say this is simpler. However, during the changeover period we will see two kinds of labels which is going to be even more confusing. Fortunately for most products there is other information on the label that you can use to compare products by actual energy consumption. Unfortunately this is not so for heaters, which only show the energy class and even this means different things for different types of heater.

Tuesday, 13 June 2017

Reasons why your freezer may be using too much electricity

Back in 2014 I reported some shockingly high energy use in a minority of freezers and fridges [1]. This was from a study of electrical appliances in general and there were only about 130 cold appliances in the sample. Now there has been a much bigger study with 998 fridges and freezers, conducted by BRE [2]. It has confirmed the earlier findings and provided more information as to the causes of the problem. In some cases the appliance was faulty but half the time the main cause was simply running on fast freeze or maximum setting all the time.

This problem mainly affects freezers. 25% of chest freezers were over-consuming and 12% of upright freezers.

Friday, 9 June 2017

Reducing my carbon footprint without saving money

Usually I focus on home energy but recently I have been thinking about reducing my whole carbon footprint. It turns out I can use the same principles I have been using for home energy across other sectors too. Some of these strategies save money, but there are ways to spend it again and still save emissions.

I reckon the footprint for me and my beloved looks something like this. Yours will probably be somewhat different – for example ours is very low on travel because neither of us commutes to work, we don’t even have a car, and we usually take our holidays in the UK by train. However we are not unusual in that goods and services is a large chunk. So what can we do to reduce emissions over all sectors?
Carbon footprint for my household, estimated based on home energy use, travel distances and spending on other goods and services.

Thursday, 25 May 2017

Do modern homes overheat more than older ones?

Modern homes have a reputation for overheating more than old ones partly because they tend to be more airtight and partly because they are often more lightweight constructions that heat up quickly. However, overheating is not an inevitable consequence. For example features such as green roofs and external window shades can make a huge difference – but apparently ‘people are resistant to changes to the aesthetic of the homes and other buildings they occupy’ and these features ‘may be resisted by house buyers’ – so builders won’t build them [1]. Is it all our own fault then?

Saturday, 13 May 2017

Should chicken be taxed higher than beef?

Meat production on farms is responsible for a sizable proportion of our greenhouse gas emissions - both directly from the animals and from producing the feed. Eating less meat is good for us in other ways too, and most of us eat much more than we need. But how to change our habits? One way is to tax meat consumption. How much should such taxes be? A comment piece by Simon Fairlie in the Guardian [1] references two conflicting sources. One, from Oxford University suggests 40% on beef and 8.5% on chicken [2]. The other, from Sweden's University of Agriculture, suggests 40% on chicken and only 28% on beef [3]. This was a surprise - I have always understood beef was much worse than chicken because cattle (and sheep) belch methane. Putting a cash value on environmental impacts is never easy but how can there by such widely differing estimates for similar products?

Monday, 1 May 2017

How much can we reduce heating demand, realistically?

Around 40% of our energy use is for heating in buildings, both space and water heating, and a large proportion of this is fuelled by gas with associated carbon emissions. We can reduce this either by switching fuel or by reducing demand or both. According to Zero Carbon Britain (ZCB) it is feasible to reduce the demand for domestic heating by 60%. However the Committee on Climate Change disagrees - they have assumed 17% in their scenarios. Which is right? Also, how much progress have we made so far?