Last year saw Australians install rooftop solar like never before, with 40% more installed in 2021 than in 2020. Solar system installations now make up 7% of the energy going into the national electricity grid.Last year saw Australians install rooftop solar like never before, with 40% more installed in 2021 than in 2020. Solar system installations now make up 7% of the energy going into the national electricity grid.