Energy Saving (Daylight) Bill

I intervened on a previous speaker about the energy that was estimated to have been saved in the previous trial between 1968 and 1971. A significant saving happened then. Any energy that we save can only benefit us and the planet. However, in view of the increased use in the 21st century, does my hon. Friend have any idea of the savings that the experiment would make, compared—in percentage terms—with the savings on the previous occasion?