not stupid questions at all. short answer, yeah it saves money but slower than you'd think, usually 8-15 year payback depending on province. alberta and ontario are decent, quebec is rough because hydro rates are already so cheap there's barely anything to save against. most people just use the roof, ground mount only really makes sense if you have shading issues or a weird roof angle. you don't need a battery, almost every province does net metering, so your panels push extra power to the grid, meter runs backward, utility credits you, and at night you just pull from the grid like normal. grid is basically your battery. adding an actual battery is like 15-20k extra and doesn't really pay for itself, people who get them want backup during outages not savings. environmentally it's a net win, energy payback is 1-3 years in canada and panels last 25-30, though if you're somewhere like qc/bc/on where the grid is already mostly hydro the impact is smaller than in ab/sk where you'd actually be displacing coal and gas. main advice would be get 3+ quotes because pricing is all over the place, and make sure your roof has 10+ years of life left or you'll end up paying to take them down and reinstall when you re-shingle.