Sunday, 31 May 2020

Water saving again

Siphoning the bath water into the water butt.
Rainfall has been very low for the last few months across the country but especially so in the East of England. Our water butt ran very low a couple of weeks ago and we have resumed emptying bath water into it. We now have a shorter hose and attachments which makes this much easier!

Here in Cambridge we get our water from an aquifer which protects us from short term droughts, but last year the level dropped to record lows and there were serious problems with low flow in important chalk stream habitats. The level did recover this last winter, but I fear a repeat this summer, if we are not careful with water. Please do what you can. Here is some more background on the issue and some water saving tips.

Sunday, 1 March 2020

4 strategies to fix carbon emissions

Greta Thunberg, school children and others are loud in their condemnation of our government's failure to address climate change [1] and they are right to be so. But it is notable that they never offer a plan of action. To do so would invite (even more) criticism because all options are unpopular with at least some people. I try to highlight some of this dilemma when I am giving a talk about personal actions to reduce GHG emissions. It is slightly off topic but I think it is important. It also raises the hope that some of these problems may be temporary.

I always start with air travel because it is such a nice example. The emissions from air travel are staggering. One return flight to New York (economy class) emits nearly 2 tonnes of CO2 equivalent, about a quarter of the average UK resident's annual total. 

So what to do about it. I offer four different strategies:
  1. Austerity: do not fly (like Greta Thunberg)
  2. Demand management by market manipulation: Use taxes or ration flying so everyone gets a fair share
  3. Technology fixes: Zero carbon aircraft
  4. Damage repair: Carbon offset or capture and store the emissions
Unsurprisingly, option 1 is never popular. You can also apply the same strategies in other sectors; below I consider meat eating and home heating as well as flying,

Friday, 10 January 2020

How should we measure the energy efficiency of a house?

You would think it was easy to measure the energy performance of a house. You probably think the key measure is the size of your annual energy bills. However, there are other ways. Are you interested in cost, carbon emissions or energy resources? To further complicate matters, measures such as carbon emissions and cost change over time, as prices change and our electricity supply mix changes.

There is a consultation on at the moment about changing the way we measure energy and carbon performance and standards for new housing - the Future Homes Consultation [1]. This is long overdue as the current methods have major flaws. However the proposed new standards have problems too and there are some very vocal critics.

Some bits of the proposals are excellent (in my view). For example the new approach is going to treat the energy from your solar panels differently according to whether you use it yourself or if you export it. Exported energy is worth only a third as much as energy you use. There is logic to this. The effect is to favour installations with battery storage because you can use much more of your own generation. Also the new standard is based on energy consumption rather than carbon emissions.

Sunday, 5 January 2020

Beefing about meat

You may be sick and tired of hearing that we all need to reduce our meat eating because of climate change, especially beef. Most people like eating meat and learning how to use alternatives is not easy, though more and more convenience foods are now available. Anyway, the NFU tell us that farming can be carbon neutral [1]. So what is the problem? Here I go through some of the arguments.


Is it true that UK beef is so much better than the global average?

Yes it is certainly true that UK beef is several times better than the global average. This graph comes from an FAO report from 2013 [2]. It does not show the UK separately from Western Europe but there is not much difference. (There have been smaller studies since. A huge international meta-analysis published in 2018 also found a similar range between best and average across different regimes. However, these were not reported by region or country [3].)
Comparing carbon emissions from beef production in different parts of the world from [2]

Monday, 18 November 2019

Trees and carbon storage

Tree planting seems to be a hot topic in the election at the moment, with the Tories and the Lib Dems both offering lavish promises. The Committee on Climate Change also advises tree planting. How much difference will this make to climate change? How much carbon is stored in a tree, or in an area of forest and how much is added to this each year? Read on for the answers.

Friday, 15 November 2019

What next for the 2050 Pathways calculator?

The 2050 Pathways Calculator was a tool to help us understand how to reduce our CO2 emissions by policy changes and behaviour shifts across all sectors of the economy. It was originally developed by the Department of Energy and Climate Change for the UK and launched in 2010 – and then adapted for other countries and a global one. The UK one is out of date now but new versions are in active use by policy makers in governments, by children in schools, by NGOs and individuals. Last Thursday I spent a day at a conference about them, with delegates from all over the world – Mexico and the USA, Malaysia, and Thailand, India, Nigeria and many from Europe too. There is a new UK calculator in the pipeline and one for the EU - both are bigger, better and easier to use.

Wednesday, 30 October 2019

Upgrading our electricity distribution networks.

Electricity North West plans to reduce the voltage of their customers' electricity supply which will reduce bills by up to £60/year - and be hardly noticeable except it will take a little longer to boil the kettle [1]. In this post I take a look at the Smart Street trial they have run to test out their concept [2]. As well as energy savings a key purpose of the trial was to evaluate new voltage regulation equipment that could delay the need to upgrade the distribution network. Reducing the voltage reduces the delivered energy and peak load, so the existing infrastructure can cope for longer.

Savings on customers bills are welcome but even more importantly (for climate change) we need to be able to install more distributed generation and run bigger loads due to heat pumps and electric vehicles. How much will that cost? A case study on low carbon heating in a town in Scotland has some answers to that [3]. The cost of the network was much less than I expected - much less than the heat pumps anyway.