How does she think net zero will be paid for? Not too bright, is she.
At the start of WWII, Purchase Tax (VAT) was increased to 33 1/3%. It was doubled in 1942, and then increased to 100% in 1943.
"War footing" means expense.
Energy will be made scarcer, which makes it more expensive.
Lucas thinks you can "invest" in making energy scarce and thereby make it cheaper.