Heat network zoning and what it means for a planning application

Heat network zone planning is the new layer that sits between your energy strategy and your planning submission in parts of England. The Energy Act 2023 created powers to designate heat network zones and to require certain buildings inside them to connect to a network, administered through a zoning coordinator rather than through the planning system itself. For a developer that means two questions at feasibility stage: is the site inside or near a prospective zone, and if it is, what does the scheme have to do about it.

The regime is being brought into force through secondary legislation rather than all at once, so the position on any given site depends on which provisions are in force and on whether a zone has actually been designated. Check the current status before you build a connection cost into an appraisal.

What a zone designation does

A designated heat network zone is a geographic area in which heat supply is expected to be met by a network rather than by individual building plant. Designation identifies the area, appoints a coordinator and sets the framework under which buildings within the zone can be required to connect.

The point of the regime is economic rather than technical. Networks need anchor loads to be viable, and the historic problem has been that each building made its own decision, so no network reached the density it needed. A zone changes the default: inside it, connection becomes the expected outcome and standing outside it requires a reason.

For planning purposes the practical consequence is that your Energy Statement can no longer treat the heat source as a free design choice in a zone. It has to address the network.

Who the coordinator is and what they can ask for

Zone coordinators are the bodies responsible for a designated zone. In practice this is expected to sit with local or combined authorities, which means the organisation asking about connection may be closely related to the one determining your application, without the two functions being the same thing.

What a coordinator needs from a developer is straightforward and arrives earlier than most teams expect: the heat load profile, the intended plant space, the point at which a connection could be made, and the programme. Supplying that in month two of a project is a conversation. Supplying it after the planning application is submitted is a delay.

Two things a coordinator cannot do are worth knowing. They do not grant planning permission, and their requirements do not displace the development plan. Where a local plan policy and a zone requirement point in different directions, that tension is resolved through the planning balance, not by the coordinator.

Connection requirements for new development

Where a requirement to connect applies, the scheme has to be designed for it, and the design implications are more than a plant room label on a drawing.

• A heat interface substation with access for the operator, sized for the load rather than for the space left over
• Distribution within the building designed for the network's flow and return temperatures, which are usually lower than a gas boiler design assumed
• Emitter sizing consistent with those temperatures, which affects room layouts
• Space and a route for the service connection from the site boundary, protected in the layout
• Metering arrangements and a location for them that the operator will accept

The temperature point is the one that catches schemes late. A layout drawn around a 70 degree flow temperature and then connected to a low temperature network needs larger emitters, and on a compact residential plan that is a real design consequence. Decide it before the elevations are fixed, not after.

Exemptions and how they are argued

The legislation contemplates exemptions from a requirement to connect, and the detail sits in secondary legislation and guidance rather than in the Act. Broadly, the arguments a developer can expect to run fall into three groups.

Technical infeasibility is the narrowest. It has to be genuine, not merely inconvenient, and "we have already ordered the heat pumps" is not infeasibility.

Equivalent or better carbon performance is the argument most schemes will reach for, particularly all-electric designs with heat pumps and on-site generation. The comparison has to be made honestly, on the network's actual carbon factor and its expected decarbonisation trajectory rather than on today's grid figure alone. That analysis sits close to the reasoning in all-electric new homes and the gas connection decision.

Cost and viability is the weakest ground as a standalone argument, and the one that most often needs to be supported by a wider appraisal rather than asserted in an energy statement.

Costs and who carries them

Connection costs divide into a capital contribution towards the network, the in-building equipment, and the ongoing heat tariff paid by the occupier. Each lands on a different party and each needs to be in the appraisal separately.

The occupier tariff is the one that generates objections. Heat networks are regulated for consumer protection under the Energy Act 2023 framework, with Ofgem as regulator, which changes the picture from the earlier position where residents on a private network had limited recourse. If your scheme is residential and a connection is proposed, expect the question at committee and have the answer ready.

Where a network is not yet built but a zone is designated, a scheme may be asked to be connection-ready rather than connected. That is a cheaper obligation and a reasonable one to negotiate, and it wants to be reflected in the Sustainability Statement as well as in the energy work, because the fabric and systems strategy has to hold up in both scenarios.

What the energy statement should say

Write the statement so that an officer can follow the decision without knowing the zoning regime in detail.

1. State whether the site is within a designated heat network zone, within an area being considered, or outside both, and give the date you checked and the source.
2. Where a zone applies, record the contact with the coordinator and what was discussed.
3. Set out the heat strategy against the energy hierarchy, showing the demand reduction achieved before the supply decision is reached.
4. Present the connection option and the alternative on comparable carbon and cost bases, with the carbon factors and their source stated.
5. Where an exemption is sought, state the ground and the evidence, and say plainly that the exemption decision is not the local planning authority's to make.
6. Describe the safeguarded plant space and connection route by reference to drawing numbers.

Energy masterplanning across a phased site adds another layer, since the first phase carries the infrastructure cost for later ones, a sequencing problem examined in energy masterplanning across a phased site.

Discharging a connection condition

Where permission is granted with a condition requiring connection or connection-readiness, discharge is evidential. Expect to provide the connection agreement or a letter from the operator, the installed substation details, commissioning records and the safeguarded route as built.

Two practical points. Conditions that require connection by a date the network cannot meet create a compliance problem for the developer that is not of their making, so negotiate a trigger tied to network availability rather than to a calendar date. And where the condition refers to a network that has not been built, ask for a fallback so the buildings can be heated and occupied while the network is completed. Officers will usually accept a temporary arrangement if it is designed to be removed.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. The heat network zoning provisions of the Energy Act 2023 are being brought into force through secondary legislation, so verify the current status and any designated zones at the time you rely on this. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.