By switching off electrical appliances rather than putting them on standby could save the average British household £37 per year, that is around 3-4% of the average annual domestic electricity consumption. But what is this in terms of overall energy consumption?
Carbon emissions for electricity are typically 0.55kg CO2/kWh giving 2640kg/year.
Carbon emissions for gas are typically 0.185kg CO2/kWh giving 2960kg/year.
Giving a total of 5600kg
So a generous 4% saving on electricity (105kg) results in a total saving of 1.9%.
Domestic energy consumption accounts for around 30% of overall UK energy consumption therefore if EVERYONE makes this saving that will result in a total reduction in carbon emissions of around 0.5%. In reality, many people will not take implement this change, more appliances will be acquired and the savings by some will be cancelled out by the profligacy of others.
In conclusion, small changes made by the conscientious few will be naught but a drop in the ocean unless many many more people get on board and make BIG changes, reducing overall energy consumption by double digit percentages year on year.