Energy statements for warehouse and logistics schemes

A warehouse energy statement behaves oddly because the building it describes uses very little regulated energy. Most local plan policies ask for a percentage reduction against the Building Regulations baseline, and in a large distribution shed that baseline is small, dominated by lighting, with heating either absent or limited to a few degrees of frost protection. Cutting a small number by a set percentage is harder than cutting a large one, and the arithmetic makes a well designed building look unambitious.

That mismatch is the thing to address head on in the submission. An officer who has only assessed housing schemes will read a 14 per cent figure as underperformance unless the statement explains why the denominator is what it is.

Regulated energy in a building nobody occupies

Part L 2021, Approved Document L Volume 2, sets a target emission rate and a primary energy target for buildings other than dwellings, modelled using approved software. Regulated energy covers fixed building services: heating, cooling, ventilation, hot water and fixed lighting. It excludes process loads.

In a distribution unit the split is unusual. Occupancy density is low, internal gains from people are negligible, and the storage volume is conditioned lightly or not at all. Lighting is the dominant regulated load, and modern high bay LED with daylight linking and presence detection already sits close to the practical floor. Once you have specified the best available lighting, there is not much regulated energy left to remove.

Meanwhile the loads that actually drive the site's electricity bill sit outside the regulated calculation entirely. Battery charging for the fleet of materials handling equipment, automation, conveyors, refrigeration in a chilled unit and the occupier's IT are unregulated. A statement that reports only regulated performance can therefore describe a building that reduces emissions on paper while the meter tells a different story.

Say both numbers. Report regulated performance against the Part L baseline because that is what policy tests, then report estimated total site energy including unregulated demand, clearly labelled as an estimate based on the design assumptions available at application stage.

Unheated, partially heated and the modelling choices behind them

The thermal treatment of the storage volume changes the result more than any other decision, and it is often not fixed when the application goes in. A speculative unit may be modelled as unheated, then fitted out by an occupier with destratification fans and gas radiant heaters.

Be explicit about the assumption. State whether the storage area is modelled as unheated, frost protected to a stated temperature, or fully conditioned, and state the consequence if the occupier changes it. Where the shell is speculative, a sensible approach is to model the shell and core as submitted and provide a sensitivity case for a heated fit-out, so the council understands the range rather than discovering it at discharge of conditions.

Office pods deserve their own treatment. They are usually the only fully conditioned part of the building, they have the highest energy intensity per square metre, and they are where fabric improvements, heat pumps and mechanical ventilation with heat recovery earn their place. Reporting the office element separately shows the design effort that a whole-building average buries.

Roof area, generation and the honest constraint

The roof is the reason these schemes can make a serious carbon case. A large rectangular roof plane with no overshadowing and a clear structural grid is close to ideal for photovoltaics, and the generation available often exceeds the building's own regulated demand by a wide margin.

The constraints are rarely about space.

• Structural capacity, since the roof was designed for snow and maintenance loading rather than an array, and retrofitting capacity into a portal frame is expensive.
• Grid connection and export capacity, which the distribution network operator confirms, and which can cap the installed capacity well below the roof's potential.
• The occupier's demand profile, because a unit running one shift exports most of its summer generation.
• Fire strategy and access, which affects array layout, isolation and the maintenance strip left clear along ridges and valleys.
• Insurance requirements, which in some cases restrict panel coverage or specify particular mounting systems.

Rooftop solar on non-domestic buildings has its own permitted development route under Schedule 2 Part 14 of the General Permitted Development Order 2015, and the capacity limit that used to apply has been amended. Check the current consolidated Order before relying on either the limit or its absence, and remember that permitted development does not help where the building itself needs planning permission anyway.

Where a vegetated roof is also proposed, the two systems can share the plane, and biosolar roofs that combine panels and a green roof explains the loading and performance trade-offs.

Policy targets written for housing, applied to sheds

Most adopted policies requiring a percentage carbon reduction were drafted with residential development in mind. In London, the London Plan 2021 requires major development to be net zero-carbon with a minimum on-site reduction of 35 per cent beyond the Building Regulations baseline, following the Be Lean, Be Clean, Be Green, Be Seen hierarchy, with any shortfall offset through a cash in lieu payment. Outside London the required figure varies by authority and some plans set none at all.

The practical difficulty is that the on-site percentage is calculated against regulated emissions. In an unheated shed, meeting 35 per cent through fabric and services alone may be arithmetically impossible once lighting is already optimised, while a roof array could generate several times the regulated demand.

Three approaches tend to work in combination. Present the percentage reduction honestly, including the stages of the hierarchy separately, so the council can see where the saving comes from. Present absolute emissions in tonnes of carbon dioxide per year alongside the percentage, because absolute figures show the scale of what the array achieves. And set out the offset position early if a shortfall remains, rather than leaving it to be negotiated after committee.

Report the numbers in a table that gives baseline, each stage of the hierarchy, and residual emissions, so nobody has to reconstruct the calculation from prose. An Energy Statement structured that way is easier for a planning officer to check and harder for a consultee to pick apart.

Where the wider sustainability case sits

Carbon in the frame, the slab and the cladding usually exceeds the operational carbon of a lightly conditioned warehouse over a reasonable study period, which makes a Whole Life Carbon Assessment more revealing for this building type than for almost any other. Concrete floor slabs designed to high flatness tolerances and heavy loading are a large part of that, and steel frame specification is another.

A Sustainability Statement can then carry the items that do not belong in the energy calculation: water efficiency, electric vehicle charging provision for staff and fleet, biodiversity measures, climate resilience and any certification target the occupier requires. Keep the documents distinct. Merging them produces a long document in which the officer cannot find the number the policy asks for.

On a phased estate, the energy strategy should be set at masterplan level so that later plots are not left with the difficult half of the target, which is the point of energy masterplanning on a phased site.

Conditions that hold the design together

The gap between a submitted energy statement and a built building is wider on industrial schemes than on housing, because the fit-out happens later and often for a different party. Conditions are what close it.

1. A condition requiring the development to be carried out in accordance with the approved energy statement, with the installed generation capacity stated in kilowatts peak.
2. A condition requiring evidence of the as-built calculation before first occupation, comparing it with the modelled figure.
3. A condition dealing with any heated fit-out of the storage volume, requiring a revised calculation where the thermal treatment changes.
4. A condition securing the electric vehicle charging provision and any passive provision for future capacity.

Ask for those wordings rather than waiting for the council's standard set. A condition drafted by the applicant, and justified in the statement, is usually accepted and is usually more workable than one written from a template.

The building most likely to be refused is not the one with the lowest percentage. It is the one whose statement never explains why the percentage is low. Set out the constraint, show the absolute saving the roof delivers, and put the offset arithmetic on the table before anyone has to ask for it.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.