Average energy-intensity improvements of around 2.4% a year to 2040 are required as part of a portfolio of measures to green the energy sector, consistent with a 2°C target. Such improvements would result in a 15% reduction in global energy demand by 2040 (IEA, 2014a). Halving global primary energy demand over 2010-35 would boost global GDP by an estimated 1.1% in 2035. This effort would require an additional USD 11.8 trillion investment in more efficient end-use technology, but would save more than USD 17.5 trillion in fuel expenditure and USD 5.9 trillion in supply-side investment (Chateau, Magne and Cozzi, 2014).