solar panels for commercial property in Portsmouth

Serving Portsmouth and the wider Hampshire area, including Gosport, Fareham, Havant.

Portsmouth is a dense, island-bound commercial market of around 208,100 people, the most concentrated city by population in the country and a place where land scarcity makes every rooftop count. The stock that owners and landlords hold here is varied: business-park offices around Lakeside North Harbour, naval and defence supply-chain industrial along the harbour and at Voyager Park, leisure and retail at Gunwharf Quays beneath the Spinnaker Tower, and the older trade and warehouse units off Walton Road and Quartremaine Road. This page is written for the party that owns the building, not the one that pays the electricity bill. For Portsmouth freeholders and investors, rooftop solar has moved from an environmental nicety to an asset-management question that touches EPC ratings, lettability, service-charge economics and exit value.

Why Portsmouth owners are looking at solar now

The binding regulation is MEES. Since 1 April 2023 it has been unlawful to let a commercial property in England and Wales below EPC E, including to sitting tenants, and that floor already strands the weakest of Portsmouth’s secondary office and older industrial stock. Looking further out, the government’s interim response of 18 June 2026 proposed an EPC B minimum by 2031 for privately-rented non-domestic buildings over 1,000 m², only where cost-effective and subject to secondary legislation. That is a proposal, not law, and the earlier “EPC C by 2027” line was scrapped, while “EPC B by 2030” was never law. But a Portsmouth landlord planning a five-to-ten-year hold should price the direction of travel into refurbishment and acquisition decisions now rather than discover the problem at rent review.

The wider market signal is hard to ignore. The British Property Federation found in October 2025 that roughly 83% of commercial buildings across seven major UK cities sit below EPC B, and CBRE put around 58% of Central London offices below that band. Portsmouth’s pre-2010 office and harbour-side warehouse stock sits squarely in that exposure. A solar array typically lifts a commercial EPC by one to three bands, never a guaranteed jump, but often enough to move a building off the strand line and keep it lettable and financeable.

The harbour economy and where the load sits

Portsmouth’s commercial energy concentration is unusual. The naval base, the defence supply chain and the marine and aerospace cluster mean a high density of energy-intensive industrial and logistics occupiers, and the city now sits within the Solent Freeport, which is pulling further industrial and supply-chain investment into the wider harbour area. High-load occupiers are exactly where rooftop solar pays back fastest, because the power is consumed on site at the point it is generated rather than exported cheaply. With an average commercial energy spend of around £38,000 a year in the city, a single daytime-operating unit can self-consume a large share of an array’s output and displace grid electricity at roughly 24 to 28 pence per kWh, against an export value nearer 12 to 16 pence.

Portsmouth City Council declared a climate emergency and works to the Portsmouth Climate Emergency Plan, with a target for the city to be carbon neutral by 2030. That sharpens the local procurement and planning environment for renewable energy and adds reputational weight to the decarbonisation case, though for owners the financial drivers above remain the deciding factor.

The ownership routes through the split incentive

The recurring obstacle for landlords is the split incentive: the freeholder funds the roof, the occupier under a typical full repairing and insuring lease takes the energy saving. There are five routes through it, and the right one depends on how the Portsmouth asset is held.

• Common-parts or landlord supply for multi-let offices around Lakeside North Harbour and the PO1 to PO6 core, where the landlord controls the meter for lifts, lighting and shared plant.
• Landlord-to-tenant PPA for single-let industrial at Voyager Park or the Airport Industrial Estate, where the freeholder owns and operates the array and sells the power to the occupier at a rate below grid.
• Roof or airspace lease, where the owner effectively sells the roof to a third party and takes a rent, useful where there is no appetite to deploy capital.
• Green leases that share the cost and benefit explicitly on a new letting or renewal.
• Owner-occupier, the simplest case, where one party captures 100% of the economics.

The structuring is the work. We engineer the ownership and lease arrangement so the right party pays and the right party benefits, which is set out in full in our guide to the split incentive and across the property-type pages for multi-let commercial buildings and industrial and logistics property.

Local cost, payback and the grid gate

Commercial rooftop solar in Portsmouth runs at roughly £700 to £1,100 per kWp installed, falling with scale, and the installation is zero-rated for VAT. A 100kWp array on a harbour-side warehouse costs in the region of £82,000 to £110,000; a 250kWp roof on a larger distribution or trade unit lands around £150,000 to £240,000. At a south-coast yield near 950 kWh per kWp a year, and with self-consumption driving the return, payback typically sits between four and eight years, and at the shorter end for the high-load, single-shift naval and marine occupiers common in the city. The Annual Investment Allowance gives 100% first-year tax relief on the spend, and rooftop solar with co-located storage is exempt from business rates in England to 31 March 2035, which on a 250kW system is worth roughly £3,000 to £8,000 a year to whoever pays the rates.

The real gate is not planning, it is the grid. Rooftop solar is permitted development in England under Class J with a 56-day prior-approval process covering design and glint-glare, and the 1MW cap on commercial rooftop solar was removed in December 2023, though listed buildings and Article 4 areas are excluded. Above roughly 50kW, the binding constraint is the G99 connection application to the local distribution network operator, and on a constrained part of the network the connection timeline and any reinforcement cost can shape the whole project. We treat that application as the first item of due diligence, not an afterthought, and the detail is in our guide to planning and grid for commercial solar.

An illustrative Portsmouth scenario

Consider a freeholder who owns a 4,000 sq m industrial unit at Voyager Park, single-let to a marine-supply tenant on a lease with five years to run and an EPC D that the tenant’s lender has started to query. The roof carries a 250kWp array, financed by the landlord under a landlord-to-tenant PPA. The tenant buys the solar power at a rate clearly below grid, the freeholder earns a return on capital rather than booking the roof as a service-charge expense, the EPC lifts toward the C-to-B range and the asset moves off the strand line. The numbers above are illustrative rather than a quote, because the connection position, the roof structure and the lease terms decide the outcome on any specific building.

That is the shape of the work across the city, from the PO1 office cores to the harbour-side industrial estates. If you hold commercial property in Portsmouth and want to understand the figures for a specific building, start with our commercial solar cost breakdown, or send the building details through the quote form and we will model the right ownership route, the likely EPC movement and the grid position before anything is committed.