Our Carbon Reduction Action Group
Members of our CRAG are committed to achieving measurable annual reductions in the carbon footprint of home energy use and transport over the next few years.
See the section below for more about what a CRAG is, and what is involved in belonging to it.
One member of the CRAG has been keeping records for more than four years and you can see the results at the foot of the right hand column >
What is a CRAG?
A group of people who want to measure their carbon footprints, and are committed to taking steps to reduce them each year.
Where did you get the name from?
I first heard about CRAGs in an article in Clean Slate, the magazine published by the Centre for Alternative Technology.
How much time will it take?
Not much more than the time it takes to keep a record of the readings from your utility bills, your annual car mileage and average fuel consumption, journeys by plane, ship and rail. These records can be kept on a spreadsheet we can send to you, or alternatively, you can pass them on to us (eg by email) for us to calculate your carbon footprint for you.
How do I get started?
Please email firstname.lastname@example.org if you would like to join in.
You can’t manage what you don’t measure – an old management adage
For anyone keen to reduce the energy consumption used for home heating, a first step is to monitor usage by reading the meter once month. The best plan is to take the readings on the last evening of the month, or in the morning of the first day of the month.
At the end of a year you will be able to see how much your usage varies from season to season. The difference between usage in the summer and winter may be very dramatic if the fuel you use for heating isn’t used for any other purpose (eg if your heating is by gas, but water heating and cooking is by electricity) and rather less so if the same fuel is used for all three.
Having noticed that winter usage is dramatically higher than summer usage, you may be wondering how much difference a cold winter would make to the figures. After all, it would be annoying to invest in some insulation and then find that your usage had increased the following year because of a much colder winter!
Degree Days can help us to understand what is really going on and to draw meaningful conclusions about the effectiveness of changes to insulation, thermostat settings, or to the heating system itself.
Degree Day data are published by various bodies – Degree Days.net publish figures for a wide range of locations and there are good quality records for Newport Pagnell. See http://www.degreedays.net/ (The Newport Pagnell weather station ID is IBUCKSNE1.
The data are usually based on 15.5° centigrade, the average-over-24-hour temperature below which most people would tend to feel they wanted to switch the central heating on.
A typical early October day with a maximum of 17° and a minimum of 10° (average 13.5°) would score 2 (ie the difference between 15.5° and 13.5°).
The 20-year monthly average degree days for this part of the country are approximately as follows (I’ve averaged and rounded some figures from the Carbon Trust for two adjacent regions)
To give you an idea of just how cold December 2010 was, the degree day figure for that month for Newport Pagnell was 471.
The graph below shows the variances between the monthly degree day data compared with the 20-year averages. Cold months are shown in blue and warm months in red. Summer months are not included.
The maths which describe the relationship between energy usage and the degree day data are shown on the Degree Days net website.
For a well insulated house, a lower base temperature may give a better correlation than 15.5°.
Here is a graph showing the moving annual degree day total (13.5° base) plotted against the moving annual total of gas usage for the author's detached house in Bletchley. The correlation between the two sets of figures is remarkable:
Lisa's 2008 and 2009 footprint
Lisa has retrospectively calculated her household carbon footprint for the last two years (and puts me to shame – her figures are very low!).
Here is a selection of the actions she has already taken, and what she plans to do in future
HOW WE CUT DOWN 2008-2009
PLANS FOR 2010
I use more electricity and perhaps gas than I might otherwise because of the way I cook. I could use less by microwaving everything but I choose not to on health and taste grounds. I use the bread machine a lot which uses power, but I save in terms of disposing of plastic bags and frequent shopping trips. I mostly bake my own biscuits and snacks, make my own soup. All require more domestic power than buying pre-prepared but are arguably more eco-friendly when you consider the bigger picture.
David’s CRAG progess
Here’s a chart of my progress over the last four years:
I've managed to reduce car mileage and electricity use, but have used more gas due to increasingly cold winters.
In 2010 I installed solar PV panels which have reduced my net electricity usage considerably. Still to do in the next few years are:
My challenge will come when one of my sons decides to move out at which point the household energy use will have to be apportioned to three people instead of four.
This is an example of the environmental impact of us choosing to carry on living in homes that are bigger than we need…..