Thursday, 9 July 2020

Lessons learnt from the Green Deal Home Improvement Fund

The latest announcement of the Green Homes Grant scheme, with vouchers of up to £5000 for homeowners to spend on energy efficiency measures [1], is strongly reminiscent of the Green Deal Home Improvement Fund (GDHIF). Back in 2014 the GDHIF offered vouchers up to £7,600 per home for measures from a menu of insulation and heating improvements. It was massively popular and sold out in 7 weeks [2]. Unfortunately there was little lasting impact for the industry as insulation rates quickly dropped back to their former levels - as you can see in this chart.

Based on National Energy Efficiency Statistics from [3]

There were many other shortcomings too including:
  • Short timescales to spend the voucher did not allow for inclement weather - it is impossible to do a good job with external wall insulation in a rainy January.
  • Only Green Deal certified installers could take part, and qualification cost time and money, which shut out many small builders who could not afford the investment.
  • The certification scheme was not adequate to protect consumers from rogue traders. In particular, any companies that failed an audit could resurface with another name and get new certification from a different body [4].
Since that time there has been growing acknowledgement of the need for a whole house approach to retrofit, rather than a measure-delivery based scheme. The Each Home Counts report got the ball rolling and now we have started to certify Retrofit Co-ordinators, whose role is to oversee a plan for each case. The goal is to avert unintended consequences from inappropriate measures or combinations of measures. These measures are part of the recently approved PAS 2035 standard and trust mark. At the moment it is voluntary except for government projects - maybe this is a good time to roll it out.

Here are some more suggestions from me:

Sunday, 28 June 2020

Will an electric heat pump increase your energy bills?

For a long time I have bemoaned the fact that while electricity has been getting cleaner and cleaner, it is not getting cheaper. Ten years ago I used to say that gas was a third the price of electricity and a third the emissions. More recently I have been saying that electricity is less than twice the emissions but four times the price. With an electric heat pump you should be able to get an efficiency of 250% or so, but this is not enough to level out the difference. Times have changed.

These days, if you are flexible in when you consume energy, which should be quite possible with a heat pump, you can get electricity at close to twice the cost of gas, so your heat pump really should work out cheaper. I anticipate your next questions are (a) where can I get this cheap electricity and (b) how does having a heat pump mean I can be flexible.

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.