Using on-line calculators
1 flight from Tarbes to London 226kg
Drive 1000km in a diesel car 5l/100km 234kg
In a year we use 2MWh and buy 1MWh.
To buy 1MWh in France, typical emission is 45g/kWh or 45t (45000kg)
Put another way, I can take 200 flights (45000/226) with electricity that we generate/save
The return journey to the supermarket we use is 26km, which is 6kg of CO. After 38 weeks of just food shopping our carbon emission is the same as a flight to London.
Our ISP reckons we use 3.8kg of CO per month = 45kg/year, which is about 8 shopping trips.