Question about calculating your household GHG emissions

[wayner]

I am working on calculating my household's GHG emissions. Last year I put in solar panels and when calculating GHG emissions I am assuming that my solar panels offset the power generated from the grid.

Here in Ontario our electricity comes from (1) Nukes, (2) Hydro, (3) Gas fired plants, and (4) wind. The mixture at any given time is shown here: http://live.gridwatch.ca/home-page.html. All of the coal plants in Ontario were shut down a few years back. And it seems that we generally are a net exporter of power.

When calculating the offset for my solar panels is it "fair" to assume that the offset is against gas plants as these would be peaking plants and my solar panels will mean that the gas plants don't need to run as much, all else being equal?

 

[dhrivnak]

I use the average mix as you are still using power at night which is mostly green but most of your production is offsetting natural gas.

 

[omgwtfbyobbq]

It depends on what mix of generators are around. Without hourly data on your production, your consumption, and the grid mix, the best you can do is guess. If you happened to have all that info, you could throw it all in a spreadsheet and see what comes out. If the carbon intensity of the grid when you're exporting electricity during the day is greater than at night when you're importing it, your system would have a net negative even if you're just offsetting consumption with your own production. If carbon intensity at night is worse, then you're looking at a net positive. Like most things, the devil's in the details.