Bristol has committed to becoming a carbon neutral city by 2030 and has launched its One City Climate Strategy Plan as a call to action to help prepare and adapt the city to achieving its net zero ambitions.

As part of this, Bristol has committed to a heat decarbonisation roadmap for using carbon neutral energy for heating and hot water and ensure it is maximising local renewable energy generation. To do this, the city is embracing a heat network. As it stands, Bristol sits in a heat network zone alongside other cities including Nottingham, Liverpool and Southampton.

In the UK, heat networks currently provide around 2 per cent of heat demand. This will need to increase significantly around in order to reach around 18 per cent over the coming years. Heat networks distribute heat or cooling from a central source or sources, and deliver it to a variety of commercial and residential property. By supplying multiple buildings, they avoid the need for individual boilers or electric heaters in every building.

The Bristol District Heat Network is able to offer a discount on the cost of heating compared to using conventional gas fired boilers or air sourced heat pumps, which is a welcome benefit for landlords with the current increases to energy prices in commercial office buildings and the respective impact this is having on service charges.

 Commercial property owners and occupiers who have clear net zero carbon commitments should now consider investing to retrofit their buildings to the heat network as a potentially viable option.

The forthcoming Energy Security Bill, due to come into effect as early as 2024, is currently aiming to make it mandatory for large non-domestic buildings to connect to the heat district network when within the zone’s boundaries.

The benefits to connecting to the heat network are:

• This new pipeline provides local infrastructure opportunities enabling local renewable energy resources and reducing reliance on fossil fuels
• Improved air quality within the city centre
• Heat networks are particularly attractive in high-density built-up areas where fabric first energy efficiency solutions are challenging, such as in historic buildings
• Avoiding the need for individual boilers and heaters

However, the complexities around retrofitting a building to connect to the Bristol Heat Network are:

• Understanding that it will deliver sufficient heat, based on the current carbon intensity of the heat network in kgCO2/kWh
• Establishing that it will meet sustainability targets by clarifying the future decarbonisation plans of the heat network and projected carbon intensity (kgCO2/kWh)
• Clarifying any assumptions behind carbon intensity calculations including network heat losses, energy storage volume, heat pump efficiency, future heat source expansion plans and future connections
• Ensuring there is sufficient physical space for the new heat exchanger plant to be installed
• The requirement for an institutionally acceptable supply contract for the provision of energy from the Heat Networks provider.

By using the above, you can complete an investment grade audit to drive energy efficiency across an entire building to include a detailed cost benefit analysis against replacing an existing heating plant and installing a new air source heat pump. This will model the likely carbon reduction, running cost reduction and any subsequent payback period.

Heat network districts help to drive the decarbonisation of heat and economic growth and social value via the local supply chain and generating employment in the region, but a decision to connect needs to be gone into with eyes open.

Further information

Contact Rupert Ward

In Plain English: Heat networks