Advising on a Low-Carbon District Heating Solution at Seaham Garden Village

Built immediately adjacent to the Coal Authority’s Dawdon Mine Water Treatment Plant, this scheme protects a vital drinking water aquifer by abstracting 100 to 150 litres per second of saline mine water up to the surface for treatment. At present this resource is simply discharged into the sea.

Seaham Garden Village will be supplied with heat from the mine water treatment scheme, which has been warmed via geothermal processes to provide a year-round continuous water supply at 18–20°C.

This renewable energy source has potential to have a practically zero-carbon footprint, and as an energy source unaffected by external factors, it will maintain a stable price and is viable enough to compete against gas suppliers.

The site will provide 1,500 homes, a primary school, shops, health and wellbeing hub, and an innovation centre.

Durham County Council (DCC) aim to reduce carbon emissions by 60% by 2030 and reach neutrality by 2050; Seaham Garden Village is an exemplar project in delivering DCC’s stated objective.

Challenge

Given the innovative and complex nature of the proposed district heat network, this project is set to be one of the first of its kind.

Currently, water from the mines is simply cleaned and discharged into the sea. There is realistic potential for 6 Megawatts of low cost, low carbon sustainable energy available for local space heating and domestic hot water use throughout the year.

The most significant challenge is changing a culture exhibited by developers, housebuilders, housing associations and private house buyers that are accustomed to a house having a gas fired heating boiler. In 2025 when the Future Homes Standard legislation is introduced, new build homes will not be able to have gas fired heating installed and instead will be future proofed with low carbon heating. Mine water sourced heat pump-based district heating provides the most carbon efficient solution to this change in market demand.

Our role has involved liaising with multiple stakeholders including the Coal Authority, Durham County Council, Environmental Agency, Tolent’s technical team, contractors, and potential equipment suppliers.

Solution

Leading the infrastructure design and coordination, a large portion of our work has been related to the mine water heat pump proposal, its low temperature nature, and its integration with the 1,500-housing stock.

From carrying out assessments including a Non-Domestic Plant Space Assessment, load assessment and innovation research, we were able to offer a raft of advice to our client and their house building partners. We demonstrated exactly how embracing this new technology would affect them in terms of changing their ways, working practices and cost estimating.

In our review of the Mine Water Energy Utilisation Feasibility, we critiqued several fundamental design assumptions and made recommended changes based on viability. These changes were incorporated by the Coal Authority team, including updating proposals produced prior to HNIP funding application and full stakeholder engagement.

With the individual development cells being let to separate house builders, we aided this process by explaining in layman’s terms the technicalities and opportunities that the scheme will bring. Rather than harbouring scepticism about the change, we found that those concerned have adopted this as an opportunity rather than a threat.

In addition, we have acted on Tolent Living’s behalf in negotiations with National Power Grid to bring a phased 20kV power network to the greenfield site.