The proceeds will be used to cut debt, with the sale part of a restructuring plan following the collapse of its original plan to sell the division to rival power group Npower.
Alistair Phillips-Davies, SSE’s chief executive, said now that it has received CMA approval preparations can start for completion, which is expected around mid-January 2020.
“We have a clear strategy around developing, operating and owning renewable energy and electricity network assets, along with growing businesses complementary to this core."
SSE’s discontinued businesses posted a loss of £512mln in its latest half-year including £489mln of asset write-downs.
The retail business employs around 8,000 staff across the UK.