Modelling and developing a neighbourhood low carbon system for five dwellings in the U.K.

This paper presents a case study of a neighbourhood low carbon energy system designed for five off-gas rural dwellings in the UK. The employment of the neighbourhood system aims to improve energy efficiency of the whole site, reduce dependency on heating oil or LPG for off-gas houses, maximize renewable energy usage on site, and minimize fuel poverty through affordable investments. System design is discussed and built on site survey, on-going monitoring and validated modelling. Simulation is carried out in dynamic model HTB2. A ROI analysis is used to examine the long-term cost-effectiveness, taking into account any maintenance and replacement cost, degradation of system performance and discounting of money over time. The neighbourhood system scenario is compared with an alternative scenario of separate systems for individual houses, in terms of energy reduction, energy self-sufficiency, CO2 reduction and pay-back time. The simulation results indicate the designed optimal neighbourhood system can achieve similar self-sufficiency as that of a separate system scenario, with more than 70% of its electricity demand met by onsite electricity production. Both the neighbourhood system approach and the separate one can achieve carbon negative for the whole site, with the former contributing to 31% more carbon reduction than the latter. The neighbourhood system can be paid back within its lifespan, while the separate system approach can’t. The payback time of the neighbourhood system can be reduced to 14 years if traditional bolt on PV system is used instead of building integrated PV. The outcome of the research demonstrated the affordability and replicability of the neighbourhood low carbon energy system, which can decrease fuel poverty, and meet government targets for CO2 reduction.