Tuesday, 18 April 2017

5 year carbon savings advice review: changes

Five years ago I devised some 'carbon saving' cards to engage people at event stalls, with ideas like 'Switch your TV off when you are not watching', 'Run the dishwasher only when it full', 'Draught strip a leaky front door', 'Eat a vegan meal once a week', 'Keep your phone for 3 years before replacing it'. As I am doing a similar stall this Saturday (at the Earth Optimism Solutions Fair) I decided to review the cards - and found big changes to carbon savings from some of the activities. Should the advice we give change too?

The cards that have changed are mainly to do with electrical or electronic appliances and the emissions have changed for several reasons.

Lower carbon emissions from electricity
Firstly, our electricity has less carbon emissions than before. The carbon factor in terms of g/kWh is down by 33% from 2012-2017. This is due to switching away from coal and towards gas or renewables for power generation. It means that the cards to do with TVs, freezers, dishwashers, tumble dryers and computers have emissions savings reduced by a third.

Improved efficiency
Secondly, some appliances are now considerably more efficient than they were, in particular TVs have. Back in 2012 the typical energy rating for a TV was C or B. Now they are usually A or A+. Going from C to A cuts energy use by about 50%; combined with the changes for electricity this means that TVs now have reduced emissions by two thirds. It hardly seems worth while advising someone to get a smaller TV to save 40 W. Over the year, at 4 hours/day this comes to about 60 kWh (about £8.50), or 20 kg CO2. This is 0.3% of a typical UK person total footprint.

Are the efficiency improvements real?
However, it may be that TVs are not really that efficient. There have been a number of news reports of some manufacturers gaming the tests, in the EU in 2015 [1] and last year in the US [2]. The main trick is to reduce brightness if they detect the test. It is likely that at least some TVs use considerably more than their energy label suggests.

Lower embodied energy from Apple products
Another big change I found was to do with the embodied energy of computers and phones. I rely on Apple for the data on these because they conveniently publish the estimated life cycle emissions on all their products [3]. Since they make a big stand on green credentials they are not necessarily typical. However, there are few others sources to rely on. So, back in 2012 my benchmark for phones was the iPhone 5 with 75 kg CO2 lifecycle emissions. Now it is an iPhone 7 with 56 kg CO2. Ignoring emissions from the in-use phase, keeping this for an extra year saves all of 8 kg/year. Similarly, my benchmark laptop was a 15" Macbook Pro at 560 kg. Now the 15" MacBook Pro with Thunderbolt is 461 kg CO2. According to Apple they have made a lot of savings by partnering with clean energy providers and by sourcing aluminium recycled from scrap or produced with low carbon electricity [4].

Electricity is still the source of a large part of our emissions, but less so for households
The most recent report from the Committee on Climate Change shows that the power industry is still a large source of carbon emissions (see chart below). But this is less true for households as only a third of electricity is used in homes [5].

Carbon emissions by sector from the CCC showing the sharp decrease in emissions from power (mainly electricity production) [6]

This next chart shows carbon emissions from gas and electricity use in a typical household using carbon factors for gas and electricity from 2012 and 2017. Electricity is now less than half the emissions. Gas (i.e. heating) is much more important. However big savings on heating are often difficult, being either expensive (insulation) or big hassle (draught management).
Carbon emissions due to typical household consumption - 12,500 kWh/year for gas and 3,200 kWh//year for electricity [7], using carbon factors from 2012 (494g/kWh) and 2017 (330 g/kWh).

Heat pumps produce less emissions than gas boilers.
The decreased emissions from electricity mean that heat pumps are  a sensible low carbon option even if they do not always perform as well as advertised. Even if you currently use gas, converting to a heat pump will save carbon emissions, even though it may not reduce your bills [8].

My new card set.
In my new set of cards there are fewer actions on appliances but I have added some on food. You can download the calculations from my website here. The set includes:

Appliances
  • Unplug mobile phone charger when not in use (zero savings with a modern charger)
  • Buy a chest freezer instead of a tall one
  • Let the sun dry your washing
  • Avoid over-filling the kettle
  • Run the dishwasher only when it is full
Heating (space and water)
  • Draught strip a leaky front door
  • Put a jumper on and turn down the thermostat one degree
  • Install a low-flow shower head
  • Shorter showers
Travel
  • Take the train and ferry to Dublin instead of flying
  • Take a break in Paris by Eurostar instead of New York by air
  • Cycle instead of driving to work
  • Share your car trip to the supermarket with a neighbour
Food
  • Go vegan one meal per week
  • Consume 100g of Californian raisins instead of 500g Californian grapes

Do send me your suggestions for more cards, ideally with data for calculating the savings.

[1] EU probes TV makers over energy efficiency test scores (BBC) Oct 2015
[2] TV industry gets its own 'dieselgate' over 'leccy consumption tests (The Register) Sep 2016
[3] Environment Reports (Apple)
[4] Climate Change is real. So is what we are doing about it. (Apple)
[5] Digest of UK Energy Statistics 2016 (www.gov.uk) July 2016
[6] Meeting Carbon Budgets : 2016 progress report to parliament (theccc.org) June 2016
[7] Typical consumption values for 2015 (OFGEM)
[8] Detailed analysis of data from heat pumps installed via the Renewable Heat Premium Payment Scheme (RHPP) (www.gov.uk) April 2017

2 comments:

  1. Hi Nicola,
    It would be useful to know what quantitative difference each of these actions on your card set would individually contribute and taken all together (for a typical household or individual), and (if possible) what percentage total reduction in energy consumption this would generate.

    ReplyDelete
  2. Did you look at the calculations I mentioned on my website?
    http://nicola.qeng-ho.org/resources/Carbon%20saving%20cards-3.pdf

    ReplyDelete