Project Summary
The UK heating sector contributes nearly one third of the country's annual carbon emissions. One solution to decarbonising the sector is low-carbon district heating(DH). According to the Climate Change Committee, DH could meet 18% of Unhating by 2050. WASH will investigate the incorporation of heat from wastewater into DH networks. The objective is to assess the feasibility of wastewater heat as a source for heat pumps that supply DH networks, provide essential knowledge to assess the potential for heat pump flexibility, and explore how water companies network operators and DNOs can work collaboratively to decarbonise DH networks.
Innovation Justification
DH networks powered by centralised heat pumps can be a flexible, low-carbon solution to reducing the UK heating sector's carbon emissions. However, due to alack of coordination currently between the DH network operators and electricity network operators and a lack of efficient sources of waste heat, there is a risk of substantial addition to peak electricity network load, which could trigger large network reinforcement costs and increased consumer electricity bills. WASH aims to address this by tapping into the potential of wastewater heat to optimise heat pump sizing and operations and enable them to operate in a more flexible manner.
Wastewater district heating is being explored in Kingston and in Galashiels(Scotland), but none of these projects consider its impacts on the electricity network. The Heatropolis SIF funded project investigates developing commercial frameworks between heat pump powered DH networks and electricity networks but does not consider the value of wastewater heat. The Full Circle SIF funded project investigates the development of a framework to best leverage waste heat from transformers rather than water and sewerage infrastructure. WASH will develop a first-of-its kind framework that will incentivise collaboration monodons, DH network operators and water and sewerage companies to decarbonise heating with minimal impact on electricity networks.
This cross-sector collaboration among partners with limited history of collaboration, along with a lack of incentive for DH networks to connect flexibly or participate in flexibility services (CRL = 3, IRL = 3) bears an element of risk.
Additionally, the limited, pilot-level exploration of this concept (TRL = 5) in the Unmakes it risky for a DNO to undertake as a BaU activity. Therefore, SIF is the most suitable funding mechanism as its structure allows partners to conduct technical feasibility assessment and then perform a demonstrator as part of the Beta Phase and improve the TRL, CRL and IRL of wastewater heat powered district heat networks to 7 or above for all three metrics. SIF mechanism offers an excellent opportunity for cross-sector collaboration, which is essential for the success of the project. The scope is appropriate as WASH focuses on a specific heat source(wastewater) and we intend to use the Discovery Phase to test this.
Impacts and Benefits
Financial -- Future reductions in the cost of operating the electricity network
Waste heat from wastewater and sewerage network infrastructure unlocks a new low-carbon heat source for district heat networks, which could contribute towards the downsizing of the centralised heat pump and allow them to operate with greater flexibility. This can reduce the peak electricity demand of the heat networks, resulting in savings of £131,000/MVA of network reinforcement avoided.
Financial -- Cost savings per annum on energy bills for consumers
Electricity suppliers are charged a Distribution Use of System (DUoS) cost, which is then passed on to end consumers and accounts for 12-15% of total bills. Improved operational flexibility and downsizing of the centralised heat pump of a heat network will reduce peak electricity consumption and associated reinforcement which will reduce DUoS on consumer bills.
Environmental -- Carbon reduction -- Direct CO2 savings per annum
As of 2018, UK heat networks supplied 14TWh of heat, but only 1TWh (7.1%) of this supply came from low-carbon sources with gas CHP technology making up
the lion's share. Thames Water estimates that waste heat from its wastewater treatment works and sewers has the potential to meet up to 10TWh of heating demand each year (71%), which equates to 2.3 million tonnes of direct CO2savings in their license area alone. If applied across Great Britain, the CO2savings realised could be significantly larger.
Environmental -- Carbon reduction -- Indirect CO2 savings per annum
Potentially reduced requirement for network infrastructure reinforcements may result in carbon emission savings from otherwise required construction works.
Revenues -- Creation of new revenue streams
Wastewater heat can unlock a new revenue stream for water and sewerage companies, who estimate that heat from billions of litres of wastewater is currently lost. The added revenue from selling this heat to district heat networks could lower their operating costs and result in lower water bills for consumers.
New to market – Services
Improved operational flexibility could enable the district heat networks to participate more actively and for longer periods of time in flexibility services and smart connection products, creating a revenue stream for flexibility as a service.
Others - Local Job Creation
The UK government predicts that the heat networks industry could attract £60-80billion in investment by 2050 which could lead to creation of long-term jobs associated with designing, building and operating heat networks and subsequently, the systems proposed in WASH.
