Heat is the biggest end use of energy in the UK - most of it is used for heating homes and providing hot water. This research project examined the feasibility of capturing large quantities of waste heat from power stations and industrial processes and then storing it underground for later use in homes and offices. It investigated the cost effectiveness and practicalities of storing large quantities of heat for long periods of time to meet a significant proportion of the UK’s winter heat demand. It evaluated the practical limits for this type of storage, the technology development needs and where in the country large-scale heat storage could be most effectively exploited. International consulting engineers Buro Happold completed the research project in 2011.This feasibility study assesses the potential for large scale geological heat storage (sometimes termed heat capture and storage) in the UK.The results of the study suggest that large scale geological heat storage is technically feasible, and depending on future energy prices, can be economically viable.The main benefits of such storage lie in the potential to improve thermal efficiency of existing and future power stations (currently around 35-55%) by using their heat output, increasing system efficiency to approximately 80%. By decoupling electricity and heat generation it can provide flexibility to deal with variations insupply and seasonal demand.In the longer term it can provide low or zero carbon heat when climate change targets mean using natural gas is not longer acceptable. Additional benefits include reducing demand on the electricity system by reducing the amount of heat demand switched from natural gas to electrically driven heat pumps.The report recommends that a pilot study be undertaken for a suggested 25MW aquifer thermal energy storage (ATES)system as close as possible to an existing district heating system in the UK. Possibilities include:Borehole Storage: Southampton, Sheffield, Nottingham, LeicesterAquifer Storage: Birmingham, Southampton, Manchester