Urban carbon and energy analysis: calculation of energy flows and emissions from residential housing clusters and assessment of sustainable energy options

摘要

In the UK, the domestic sector accounts for around 30% of fuel-use and energy related carbon emissions, and therefore has the potential to deliver significant reductions in carbon dioxide emissions. The purpose of this work is to form and examine various heat and electricity supply scenarios at the street-level and identify which of these scenarios offer the most potential to reduce consumption of resources and carbon dioxide emissions. The path to realisation of a reduction in carbon emissions from the domestic sector incorporates three consecutive steps: (1) saving energy, (2) use of renewables and (3) use energy as efficiently as possible, including fossil fuels. In reality, there is a strong interaction between all three steps and often they take place simultaneously. The first two steps tend to minimise the use of fossil fuels, but not to eliminate them. In this work it is recognised that in mature urban regions fossil fuels cannot be readily displaced completely, but can be used in a more efficient way. This research considers what can be achieved by applying at or near to market technologies at the street level microgrid scale, such as Combined Heat and Power (CHP). The renewable energy technologies considered were photovoltaics (PV) for electricity generation, solar thermal for domestic hot water heating and ground source heat pumps (GSHP) for space heating. For the development of the models, the transient simulation package TRNSYS was used and a residential area in Southampton that represents a typical UK area, was chosen as a case study. The notion of combining a number of houses to form a local microgrid proved to be beneficial for all the technologies examined in this research. It was shown that renewable energy microtechnologies can improve their carbon performance up to 10% when operating as a microgrid, whilst estimated benefits were even greater for CHP systems. Parallel operation strategies were also investigated and it was shown that they have the potential to deliver further savings from microgrid schemes. Microgrids, although their high capital costs, were estimated to have better financial performance compared with the single house level for many of the cases examined. Increased generation and lower heating demand were the key outcomes due to the impact of change in climate