Strategic Innovation Fund

Full Circle

Project Data

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This project is developing a new industry-leading framework to use waste heat from electricity transformers to provide heating to nearby customers.

Full Circle is specifically looking at a substation in Wandsworth which is right next to a residential complex that is doing works on their heat network. The heat from the Wandsworth grid transformers will pre-heat the input to the heat network, reducing the overall amount of electricity to power the heat pump to provide heat to customer homes.

What is the project about?

Electricity-powered heat networks are an effective solution to heat decarbonisation. However, with the current energy crisis and market conditions, electrifying heat sources is still expensive for customers and leads to increased demands on the electricity network. Electricity transformers experience heat losses, which can be used as a supplementary heat source for local heat networks. The project addresses the relationship between the decarbonisation of heat and the electricity network. 

During the initial Discovery Phase, the project defined this opportunity more clearly for the different users. UK Power Networks has a grid substation in Wandsworth, located 200m away from a heat network Energy Centre.  

SGN is refurbishing a previous gas site at the same location into a residential complex connected to this heat network, with the aim to decarbonise it. This presents a unique opportunity for a demonstrator project to turn the concept into reality by using the power transformers’ losses as a heat source for the local district heating network. During Discovery, it was assessed that the amount of heat that could be provided from transformers could provide a significant proportion of the heat required by the heat network. 

How we’re doing it

A techno-economic appraisal was carried out in Discovery Phase. It presented a strong case for the opportunity at the Wandsworth substation and neighbouring SGN Gasworks development. This project is focused on solving the needs of all the stakeholders in this value chain: the heat network and property developers, electricity network and finally the end customers. For the heat network developers, ESCos and end customers they will benefit from improved coefficient of performance (COP) for the heating system all year round and reduced electricity and gas costs. For the electricity network, the benefits will come from potentially reduced O&M costs due to recovered waste heat. 

The Alpha phase of the project is completing a detailed design of the Transformer Heat Recovery. The project is being delivered through a partnership between UK Power Networks, SGN Commercial Services, ARUP and Atelier10. 

What makes it innovative

The pilot project could potentially become the first service of supplying waste heat provided by a DNO to a heat network in the UK. If successful, the learning can be used to de-risk similar projects across the UK. The innovation of Full Circle is about bringing a concept to reality on the network side in collaboration with new stakeholders. Full Circle will also test what potential regulatory and commercial arrangements that enable the scheme to be rolled out across DNOs. 

Although heat recovery is a well-established concept, many past projects have not progressed further than feasibility study or experiments. This can be attributed to distance between power transformers and heat demand, as well as limited commercial viability 

What we’re learning

This project has clear benefits as extracting the heat from the transformers will reduce peak operating temperatures, increasing asset life cycle. If most of the heat required for the end users heating comes from the transformers’ waste heat, then less energy needs to be generated from higher cost and carbon sources. This is based on an average annual transformer heat volume and temperature recovery profile meeting 75.9% of the heat demand of 2,752 MWh with recovered heat of the site annual heat demand of 3,626 MWh. 

Following an assessment of several options at the Discovery phase, oil-water heat exchangers paired with a water-to-water heat pumps were selected due to this options most efficient heat transfer process, lowest costs and least impact on the site. This approach is also the easiest to modify in future to meet potential increases in demand. 

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