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?