Three different numbers get called a saving, and only one of them is money you stop spending. The biggest saving comes from units you generate and use yourself, displacing electricity bought at the day rate. The second comes from charging a battery cheaply overnight and using it during the day. The third, and smallest, is export income under the Smart Export Guarantee.
A unit you use yourself is worth more than a unit you sell. Any quotation built mainly on export income is built on the cheapest of the three.