The document discusses the challenges of delivering affordable, secure, and low carbon energy for social housing, known as the "energy trilemma". It notes that 85% of existing houses will still be standing in 2050 and most do not meet thermal efficiency targets, requiring retrofitting thousands of homes per year across local authorities. Solutions discussed include improving energy efficiency through insulation, upgrading heating controls, tackling fuel poverty by reducing costs and increasing income, and accessing available funding programs.