The 2017 edition of BP’s Energy Outlook has some interesting data for global energy demand (ignore their thoughts on non-renewable usage for 2035, that's no way to save a planet!). "Global energy demand is estimated to increase by around 30%, an average growth of 1.3%/year, driven by increasing prosperity in developing countries, by 2035 a value partially offset by rapid gains in energy efficiency." What's the first thing that comes to your mind regarding energy efficiency?