Introduction This chapter aims to help the reader implement the energy strategy developed during the conceptual stages of design or masterplan as outlined in Chapter 2.6 Energy Strategy and Infrastructure. Operational energy is defined here as that consumed by the environmental services, heating of domestic hot water, circulating pumps, lighting, consumer goods and any processes involved in the operation of the building and any activities therein. Operational carbon is the carbon dioxide emissions associated with the generation of operational energy. The operational energy is dependent upon the energy demand, the efficiency of generation within the building or development and the transmission losses between the point of generation and demand. The associated carbon dioxide emissions depend on the fuel used to generate heat and electricity and the ‘carbon intensity’ of that fuel in kgCO2/kWh. The carbon intensity of electricity generated at power stations depends on the mix of fuels used and varies from country to country and even from hour to hour in any given country. For example, because of its high proportion of nuclear power, France generates electricity with an average carbon intensity which is 15-20 per cent of that in the UK, whilst its dependence on coal gives Poland electricity generation an intensity around 80-90 per cent higher than the UK; China emits 50-60 per cent more carbon per kWh than the UK. The carbon intensity of natural gas on the other hand is around 35 per cent of that for electricity generated in the UK, based on the most recent CO2 emission factors (carbon intensity) proposed by BRE for the revised Standard Assessment Procedure (SAP) for dwellings (BRE, 2009) for use in the 2010 revision to Part L1A of the Building Regulations. The carbon intensities proposed in Table 12 of SAP 2009 are 0.591kgCO2/kWh for grid electricity and 0.206kgCO2/kWh for natural gas.