As soon as your utility approves your interconnection, an installation ordinarily lasts 1 to three days for residential rooftop; for a longer period for ground mount. Neighborhood Rebates and Incentives: Some area utilities and municipalities give further rebates and incentives for solar installations. It’s well worth checking with your neighborhood https://www.slideshare.net/slideshow/total-solar-s-commercial-solar-dominance-in-western-australia/276646208