Showing posts with label Carbon. Show all posts
Showing posts with label Carbon. Show all posts

Saturday, 29 February 2020


Been thinking a lot about carbon today, as it's the last day of February when I check our car mileage, gas, electricity and solar meters. I do this on the first day of each month and have been for the past 14 months to monitor how much energy we use.
Above is a graphical representation of this data. The wine-coloured line is total emissions, which is the sum of gas, electricity and car usage, minus the emissions avoided due to our solar panels.

To calculate the emissions from using our hybrid Toyota Auris, I've taken into account manufacture of fuel and production of the car as well as the combustion of the fuel, per mile as described here ( According to the dashboard display the fuel efficiency rates between 56-58 mpg.

For gas usage I first had to convert ft3 to kwh using the following calculation from here (

Here's how to convert cubic feet (ft3) to kWh from your gas meter reading. 482 unit used X 2.83 to convert to cubic metres X 1.02264 X 39.2 calorific value divided by 3.6 provides 15,189 kWh. At 2.84p/kWh provides an estimated bill of £431.38. 482 x 2.83 x 1.02264 x 39.2 ÷ 3.6 = 15,189 x 2.84 = £431.38.

Then I multiplied it by 0.18 as described here (

For electricity usage I multiplied by 0.2733 as used by the same carbon calculator website. For solar, the same, except negative.

If my calculations are correct (doubtful) then the above graph should be representative of our family's CO2 emissions in kg for the past 14 months.

Some things to note: I cycle more in the summer months when the weather is better, and the mpg rating of our car is also better in the summer months.

We went on holiday to Legoland in August 2019, which may explain why that reading is so low across the board.

Interestingly the 1/8/19 readings reveal that we generated so much solar power that it offset the use of car, electricity and gas combined.

Here's a pie chart:
As can be seen from this, car usage is by far our worst means of CO2 emissions at about 57%. And it's a hybrid.
Looking again at the above line-graph, the difference between summer and winter emissions is quite shocking. From 75 kg in August 2019 all the way up to 525 kg at the start of data collection in Jan 2019.

So what can be done? It's cold in winter and there's more sunlight in summer. There's not much I can do about that. But the car is screwing everything.

Big time.