United Kingdom set an ambitious and legally binding target to reduce her carbon emissions in 2050 by 80% against the 1990 levels. Buildings are responsible for about 40% of UK's carbon emission and since more than 75% of the buildings for 2050 are already on ground considering the current rate of demolition, it is important to access the capacity of current retrofitting and onsite renewable technologies for already existing buildings to meet this target. This work carried out an extensive literature search on topics relevant to the research. A base case scenario was modelled of a...