The Potential of Reducing Carbon Emissions by Integrating Urban Water Systems and Renewable Energy Sources at a Community Scale

 

 This study presents a novel take on the energy-water nex­us, exploring the coupling of local distributed water as­sets and renewable generation to attempt to replace CO2 emitting residential heat demand. It first explores the opportunity for the generation and storage of renewable energy (potential and heat energy) available within local water distribution and wastewater collection networks. Secondly, it defines the potential reduction in CO2 emis­sions that could be achieved at a community level, if local wind and solar renewable energy sources can be linked in­telligently with the energy storage capabilities of the local water distribution and wastewater collection networks. An integrated system consisting of wind turbines, solar PV panels, a turbine linked to a water service reservoir, a small number of heat pumps linked to the wastewa­ter collection network and a non-renewable source was modelled. A simulation tool is developed to estimate the amount and temporal pattern of energy availability from renewable sources, such as PV, wind, water stored in service reservoirs and heat recovered from sewers. This tool then optimises the mix of energy sources at hourly intervals throughout the year to match residential heat demand, which is a major source of CO2 emissions in the UK. Simulations are run for a community of 1000 UK households for three different locations to test how the renewable energy obtained from the water supply and wastewater collection networks can reduce and re­place non-renewable energy. Results show that the inte­grated water-energy system could satisfy the community residential heat demand for up to 63% of the time in a year for a range of locations in the UK and reducethe associated CO2 by approximately 60%when compared to all heat demand being satisfied by natural gas. On a na­tional scale, the introduction of such intelligent systems could make a significant cut to UK’s CO2 emissions. A more detailed analysis of the simulations indicates the renewable configuration that minimises the CO2 emis­sions can reliably meet the residential heat demand in the summer. This work shows that integrating water and ener­gy systems at city and neighbourhood scale can bring sig­nificant economic and environmental benefits, and may be an approach that would help the UK meet its CO2 emission obligations by substantiallyreducing the18% of CO2 emission (currently estimated to be) related to do­mestic heat use.

Author(s): F Liu

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