Sustainable development, balancing economic and social development with environmental protection, has become a modern paradigm in our technological age. The British government, amongst others, regards science as being important in underpinning the move towards sustainability. However, many of the principles that bolster the three pillars of sustainable development - 'people, prosperity and planet' - are often viewed as being unscientific by sceptical natural and social scientists. But these principles are no different from the rules of thumb that engineers typically employ to design technological systems. The links between science, technology and the need to achieve environmental sustainability are explored here mainly in the context of the energy sector, which accounts for ninety-five per cent of carbon dioxide emissions in the UK. It is argued that the UK national academies of science and engineering tend to provide policy advice to government that favours 'advanced' technologies. They advocate support for such technologies often without regard for the results of science based integrated appraisal methods or for the need to engage in wider stakeholder dialogue. Greater attention is paid to 'hardware' than to, for example, energy efficiency or resource productivity more generally. The national academies could instead place themselves at the forefront of moves towards sustainability, by locating themselves more firmly in the vanguard of those devising a sustainability assessment framework.