The original 1:1 ratio was set for mechanical reasons I believe. One unit of energy coming in from the grid spins the meter a certain amount, one unit going back to the grid winds the meter back to where it started from. I think I read that the first solar panel user just plugged in without telling anyone and it just kind of worked so everyone adopted it and not enough people had solar for it to matter very much.<p>For similar reasons, most people pay a single energy rate despite peak generation costing much more to generate. With more modern meters you can have off-peak tariffs or even more complicated schemes.<p>Now of course, solar starts to matter as uptake rises, but there&#x27;s no reason to assume that the energy is necessarily worth less than the retail rate (in which case the homeowner would be subsidising the utility rather than vice versa). Solar correlates well with peak loads on both a daily and yearly cycle so the cost of generation avoided at those specific times may well be much higher than even the retail rate. As far as I can tell the wholesale rate they mention is the average for the whole year, not just the peaks when solar is contributing.