We cannot have a successful 100 per cent renewable energy economy without putting energy efficiency first. Indeed this forms part of an integrated decentralised energy economy held together through digitalisation and consumer choices. Hitherto the energy system has taken the machines and infrastructure that consumes energy as an external concern. But now this infrastructure has to be integrated and callibrated and managed as part of the energy system itself. See this page for more discussion of energy efficiency issues: Energy Efficiency
See also an article by Jan Rosenow and Richard Lowes about heat decarbonisation by smart electrification which summarises some key issues. This has a link to an excellent report which you can download.