Calculation for carbon saved per kWh generated by solar PV?

jamesingram

If the nat. grid was/is reactive enough to reduce primary energy use due to your PV export not used on HW then , as Roger suggests using gas will reduce CO2 emitted for the given task of heating your HW.

PV used for a task when a less carbon intense option is available therefore has a 'carbon footprint'.
In the UK gas is a cleaner fuel than electricity ( in many ways)

The question is really , Is the grid reactive enough to notice?

rogerblack

celerity wrote: »

If my chickens lay enough eggs that I can regularly give my neighbour half a dozen for free, but one day I decide to feed one to my dog so only donate five, I'd be a bit put out if he accused me of costing him an egg .

/\dam

I'd recast this slightly.

'If my chickens that I bought encouraged by a government grant per egg, which my neighbor pays for from his taxes' ...

If one person does this, then clearly there is going to be no effect - but if - for example - it becomes possible to purchase devices to turn on water heaters so they preferentially run on solar, then ten thousand of these installed across the country soon adds up.

And while yes, solar panels are a net saving of CO2, if they are just used to replace gas heating, the saving is considerably reduced, and the taxation of other users based on an initial rational of saving CO2 becomes even more questionable.