Retail Park, South West — 420 kWp Rooftop + Car-Park Canopy

This is a representative project profile, not a named real client. It is drawn from the patterns we see repeatedly on multi-tenant retail assets and is written to show how the numbers and the legal structure fit together — figures are illustrative and any real scheme would carry its own G99 study, roof survey and EPC assessment. We have done it this way because honest worked examples are more useful to an owner than a flattering case study you cannot check.

The asset: a retail park on the edge of Bristol. Eight units on full repairing and insuring (FRI) leases — a mid-box DIY anchor, a discount food operator, a pet superstore, a couple of fashion units and a drive-thru — plus a 180-space surface car park and a small management suite. Total roof area across the terraces is large and flat, which is the single best thing a retail park has going for it from a solar point of view. The landlord came to us because the asset’s EPC sat at a band D and the next rent reviews and lease events were close enough that lettability, not just energy cost, was the concern.

The retail MEES exposure

Retail is where the Minimum Energy Efficiency Standards bite hardest in practice, because the stock is older and the floorplates are deep. Since 1 April 2023 it has been unlawful to continue letting a commercial property in England and Wales below EPC E, even to a sitting tenant, without a valid exemption. That is the binding law today. Savills has estimated that roughly 185 million sq ft of UK retail space is at risk of becoming difficult to let on energy grounds — retail parks sit squarely inside that figure.

A band D is compliant now, but it is not a comfortable place to sit. The government’s interim response of 18 June 2026 proposed that privately-rented non-domestic buildings over 1,000 m² reach EPC B by 2031, where cost-effective and subject to secondary legislation. That is a proposal, not law, and the earlier “EPC C by 2027” target was scrapped. But an owner planning a five-to-ten-year hold has to price the direction of travel. Moving this asset from D toward B now removes the refurbishment cliff from the next sale or refinancing conversation. Solar typically lifts a commercial EPC by one to three bands — never a guaranteed jump — and on this profile, modelled alongside LED and controls upgrades in the common parts, the assessment supported a move from D to B.

The canopy and rooftop design

We combined two generation surfaces. The terrace roofs took roughly 320 kWp of in-roof and ballasted panels, sized to the units’ structural capacity and to each tenant’s daytime load. The car park took a Class OA solar canopy of around 100 kWp over the busiest 70 spaces.

The canopy matters for three reasons. First, generation: car-park canopies face open sky with no shading and earn their keep. Second, planning: since the 1 MW cap on commercial rooftop solar was removed on 21 December 2023, rooftop solar is permitted development under Class J with a 56-day prior-approval step, and car-park canopies fall under Class OA — so the scheme proceeds without a full planning application, though prior approval still tests design and glint-glare and is not a free pass. Third, amenity: the canopy carries EV chargers and gives shoppers covered parking, which is a genuine tenant-attraction and dwell-time argument at lease renewal. The grid connection — a G99 application above roughly 50 kW — was the real timing constraint, as it almost always is, and shaped the final export ceiling. Our planning and grid guide sets out that sequence in full.

The multi-tenant structure

A retail park is the textbook split-incentive problem: the landlord owns the roof, the tenants pay the energy bills, and FRI leases mean the landlord captures none of the saving by default. We solved it on two tracks.

The common-parts load — car-park lighting, the management suite, pumps and the EV chargers — is the landlord’s own supply, so that share of generation displaces grid electricity the landlord already pays for at commercial day rates of around 24 to 28p per kWh. The larger share went to tenants under individual power purchase agreements (PPAs): each unit buys solar generated on its own roof at a tariff set below the grid import price, the landlord retains ownership of the system, and the tenant takes a saving with no capital outlay. Retail’s daytime trading pattern is what makes this work — demand and generation line up through the trading day, pushing self-consumption high and leaning far less on export. Surplus is exported under a Smart Export Guarantee tariff, which is a useful top-up at roughly 12 to 16p per kWh, not the headline.

On the tax and rates side, the landlord claims the Annual Investment Allowance against the capital, and the rooftop and co-located storage qualify for the business-rates exemption that runs to 31 March 2035 in England.

Outcome

Across common-parts displacement, the blended PPA margin and SEG export, the modelled benefit to the landlord lands near £88,000 a year, with additional revenue from the EV chargers on the canopy, for a payback of about 6.1 years on the illustrative capital. The harder-to-price wins sit alongside that: an EPC moved from D to B, eight tenants on a lower energy cost with a covered-parking and EV amenity story to tell at renewal, and a MEES question taken off the table for the next sale. For a retail asset, protecting lettability is frequently worth more than the energy line itself.

Illustrative quote

“We were treating this as an energy decision and it turned out to be an asset decision. The PPAs meant our tenants benefited without us having to negotiate a single rent change, and getting the EPC to a B before the next refinancing was the part that actually moved the valuation conversation.” — representative landlord; illustrative, not a real named client.

If you own a retail park or a multi-let retail asset and want to see how a rooftop-plus-canopy scheme and a common-parts-plus-PPA structure would model on your own roof areas, tenancy schedule and EPC, request a quote and we will build the worked numbers around your asset rather than a representative one.