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Karen Fletcher looks at the vast potential from heat networks

With heat decarbonisation an essential element of the UK’s Net Zero strategy, it’s vital to find technologies that will allow us to leave gas behind.

Heat pumps have received significant attention as a primary tool for taking homes and other buildings onto electric heating.

But in its Ten Point Plan for a Green Industrial Revolution, the government also highlighted the potential of heat networks as a replacement for gas boilers.

Heat networks (also referred to as district heating) use heat from a single source and circulate this around homes or buildings via pipes carrying hot water.

Traditionally, they’ve been high-temperature systems that use gas boilers or CHP as the ‘energy centre’.

It seems that the UK’s low-carbon heat network is set for lift-off

Karen Fletcher Rocket Karen Fletcher Editor The Sectorscope

Low-carbon heat networks

The vision for future heat networks is that they will be low-carbon, using large-scale heat pumps to provide the initial heat energy, for example.

Alternative heat sources include extracted heat from factories or waste incineration. In London, tests are underway to use heat extracted from the Underground network.

The benefits of heat networks go beyond carbon reduction.

In high-density urban areas, they are often the lowest-cost, low-carbon heating option.

They offer a communal solution that can provide heat to a range of homes and businesses by capturing or generating heat locally.

Estimates are that by 2050, the UK could source about 20% of its heating needs from low-carbon heat networks.

Currently, it’s only about 2%, or around 200,000 buildings, which means there is quite a journey ahead.

Existing technology

The good news is that the UK has the technology to increase its heat network use.

The industry is also ensuring that performance standards are in place. For example, anticipating market growth, BESA has updated its HIU (heat interface unit) test standard.

The test is now on a pass/fail basis in line with the Heat Networks Technical Assurance Scheme (HNTAS). Without a pass, an HIU can’t be used in a heat network system.

The barriers to growth are, therefore, more operational and administrative.

An attractive option

However, new legislation is set to make sweeping changes to the UK’s heat network market which could see rapid growth and finally make this a more attractive option for low-carbon heating.

The Energy Bill (which has navigated its final reading in Parliament) could become an Act in early 2024. It will introduce new rules that put low-carbon heat networks on the map, literally and figuratively.

Most importantly, the Bill includes greater protections for heat network customers. Ofgem protects gas and electricity users. Heat networks are unregulated, putting customers at a disadvantage. However, once the Act is in place, heat networks will fall under the remit of Ofgem, giving customers protection and peace of mind.

In addition, the Act will introduce technical minimum standards for heat networks, which will include carbon emissions limits.  These will be mandatory and must be specified from the design stage.

Technical assurance

There will also be an assurance scheme for these technical standards, along with an assessment and certification programme. 

Speaking at the BESA National Conference on 12th October, Phil Jones of Building Low Carbon Solutions and representing the Department of Energy Security and Net Zero, commented: “In eighteen months, all heat networks will have to be certified under HNTAS. The key principles are that it will be outcomes-focused and based on certification at design and construction. The scheme will also be deliverable, affordable and proportionate for schemes of all sizes.”

The government has already worked on proposals for heat network zoning, which point to areas where networks could be most successfully implemented.  In these hot spots, the new regulation will mandate that certain types of buildings connect to heat networks, particularly where they are high-heat users.

With technical standards, mapping, legislation and training in place, it seems that the UK’s low-carbon heat network is set for lift-off.

Karen Fletcher, Editor The Sectorscope