'Energy auditing' as a technique for obtaining a 'snapshot' of the energy flows in a city or urban conurbation is discussed in the context of meeting national and international targets for CO2 emissions abatement. An audit methodology is presented which addresses the key questions: Who needs to be involved in the audit? How should the city or conurbation be divided? What data are required? How might these data be obtained and then analysed? Which are the areas of significant consumption? A basis for setting local targets for reducing future energy consumption and CO2 emissions is presented. The scope for auditing major cities and conurbations in the United Kingdom is identified with reference to implementing Local Agenda 21 and satisfying CO2 emissions reduction targets.