Embodied energy analysis is used to evaluate the total energy consumed by any product during all the stages leading up to its manufacture and delivery and can also be used to determine the energy-related environmental impacts such as CO2 emissions of buildings and other built infrastructure. In the wake of increase global awareness on climate change and the strong link between global warming and CO2 emissions, the role of new and improved analytical models to evaluate the energy embodied in products and its associated environmental impacts therefore takes an important role in environmental research studies. The development of a new hybrid embodied energy analysis model which methodologically improves the accuracy of the energy intensity of the construction sector is presented in this paper. This hybrid methodology is applied to four built infrastructure and their respective energy intensities determined. The four construction projects are; a bridge and three different building types. The building types are- a 3-bedroom terrace house, a 3-bedroom semi-detached house and a 4 bedroom detached house all in Dublin, Ireland. The bridge is for a railway line spanning Cork-to-Midleton in County Cork, Ireland. A variability and uncertainty analysis termed applicability error is carried out to determine the inaccuracy in using the sectoral or average construction sector energy intensity rather than the sub-sectoral energy intensities
