The Committee on Climate Change suggests that we need to decarbonise all heat in buildings by 2050 to achieve the Net Zero emissions targets. The electrification of heat supply, through either direct electric heating or heat pumps, seems more likely to be realised in practice. However, the complete electrification of heat will result in much higher electricity demand in winter than in summer. Furthermore, due to the consistency of ambient temperature, it will also lead to electricity demand spikiness which is a big challenge for the grid. The HARVEST project will develop a new solution that can absorb and accumulate the curtailed/waste renewable electricity all around the year using thermochemical heat storage technology and then convert and magnify the heat output in winter and cooling output in summer using heat pump technology. The unique features of the proposed solution are: (1) the microwave-assisted process to flexibly absorb renewable electricity; and (2) the compact and efficient regeneration process by direct contact reaction between thermochemical heat storage materials and ammonia solution. We have established a strong multidisciplinary consortium, consisting of leading researchers from the University of Birmingham, the University of Edinburgh, and the University College London, to address the key challenges in both the scientific/technological aspects and social aspects. Our research will significantly contribute to several identified approaches in the 'Decarbonising Heating and Cooling 2' call document, in particular, the 'new technologies of heating and/or cooling' and 'new methods or significant developments for heat storage or cold storage'. Our research is also further supported by the UK and international partners to maximise knowledge exchange and impact delivery.