Sector S10 · Offices

Commercial solar finance for offices

Office solar projects are governed less by raw electricity economics than by the landlord-tenant split, EPC compliance pressure, and ESG-driven occupier expectations. Owner-occupiers see the strongest direct economics; multi-let landlords face structural challenges that need careful contractual design; tenants in long leases sometimes find their landlord more receptive than the conventional wisdom suggests.

Sector finance angle

For owner-occupier offices, capital purchase or green loan typically lead — daytime-heavy demand profiles support strong self-consumption, and FYA capture works on the trading subsidiary even if the holding entity is investment-only. For multi-let landlords, the lease drafting matters more than the system specification — green-rent uplift mechanisms, capex pass-through clauses, and lease-renewal alignment are the deciding factors. For tenant occupiers in long leases, third-party PPA structures bypass the capex blockage altogether.

Finance routes for offices

F01

Capital purchase (owner-occupier)

Profitable trading companies occupying their own offices typically run capital purchase as the strongest economic structure — straightforward FYA capture, no covenant complications, full lifetime savings.

F02

Green loan (owner-occupier)

Where capex preservation matters, green loan over 7–10 years preserves working capital while still capturing FYA tax allowances. Strong fit for office occupiers planning growth investment.

F03

Tenant-funded with rent abatement

Long-tenure office tenants (10+ years remaining lease) can fund solar themselves with a rent-abatement clause negotiated as compensation. Practical only with cooperative landlord and clear lease drafting.

F04

Landlord-funded with green-rent

Landlord funds solar; tenant pays a green-rent premium on top of base rent reflecting partial saving capture. Works best on long-let single-tenant buildings.

F05

Third-party PPA

Specialist PPA developer installs and owns the solar; landlord receives ground rent, tenant buys electricity below grid rate. Cleanest for multi-let or short-tenancy buildings.

Typical project profile

Typical office solar project: 50–250 kWp on the roof of a 5,000–15,000m² mid-sized commercial office building. £/kWp at the higher end of the commercial range (£800–£1,000) reflecting more complex roof access on multi-storey buildings. Self-consumption typically strong on weekday-only office demand profiles (75–85%). Annual saving £15k–£90k depending on size and building electrification.

Recent project

London Bridge multi-let office: 180kWp installed across the south-facing roofline. Landlord-funded under a 12-year facility from a green-debt provider. Tenants pay a green-rent uplift of 0.8% on base rent. Project IRR for landlord: 11% post-tax. Tenant ESG reporting position materially improved.

EPC, ESG, and procurement context

EPC and MEES considerations are real for offices — the Minimum Energy Efficiency Standards regime requires E or above to let, with C the post-2030 target. Solar PV materially supports EPC ratings (typically 5–15 point uplift depending on baseline) and is one of the easier interventions to deliver alongside lighting and HVAC upgrades.

Offices FAQs

Does solar PV improve our office EPC rating?

Yes — solar PV is recognised in EPC calculations as a renewable energy contribution, and typically delivers a 5–15 point EPC score uplift on a typical office building. The exact uplift depends on system size relative to building floor area, building thermal performance baseline, and roof orientation. For an office sitting near the C/D boundary, well-sized solar can reliably move the rating up one band.

How does the landlord-tenant split usually resolve in offices?

Three workable solutions: (a) tenant-funded with rent abatement at break — works on long-let single-tenant offices; (b) landlord-funded with green-rent uplift — works where landlord has cheaper cost of capital; (c) third-party PPA — works for multi-let buildings or where neither party wants to deal with the project. We assess each on the lease, occupation, and capital structure before recommending.

What's the typical office self-consumption percentage?

Standard 9–6 office occupancy with HVAC, lighting, IT, and small-scale catering typically runs 75–85% self-consumption on a well-sized solar system. Heavier electrification (full electric heating, EV charging, heavy-IT loads) pushes self-consumption toward 90%. Weekend-shutdown offices may run lower (65–75%) — system sizing should reflect that.

Can solar PV count toward our ESG reporting?

Yes — solar PV directly contributes to Scope 2 emission reductions (using less grid electricity reduces purchased-power emissions) and supports broader ESG reporting frameworks (TCFD climate-related disclosures, SECR mandatory reporting, voluntary CDP). The carbon savings need to be measurement-grade — meter-monitored, not estimated — for inclusion in audited disclosures. Modern monitoring portals provide this data routinely.

Commercial solar for offices — detailed guide

UK commercial offices face a distinctive set of sustainability compliance drivers — MEES, TCFD, SECR (Streamlined Energy and Carbon Reporting), and increasingly stringent tenant sustainability requirements — that are making solar installations a near-essential element of office building management strategy, independent of the financial return alone.

Office electricity demand profile and solar fit

Office electricity consumption is dominated by HVAC (typically 35–45%), lighting (20–30%), IT/servers (15–20%), and lifts/other services. Crucially, the occupational hours (typically 7am–7pm weekdays, lower at weekends) align well with solar generation — producing self-consumption ratios of 60–75% for a single-tenant occupied building and 50–65% for multi-let offices with lower occupancy uncertainty.

Office type	GIA (m²)	Annual electricity (kWh)	Typical solar size	Annual saving estimate
Small HQ (1,000–3,000m²)	1,000–3,000	150,000–500,000	30–100kWp	£9,000–£26,000
Mid-size office (3,000–10,000m²)	3,000–10,000	500,000–1.5m	100–300kWp	£26,000–£72,000
Large HQ / campus (10,000–30,000m²)	10,000–30,000	1.5m–4m	300kWp–1MWp	£72,000–£192,000
Business park (multi-building)	Total 15,000–100,000m²	Variable by occupancy	500kWp–3MWp	Project-specific

MEES, ESOS, and SECR compliance drivers

MEES for commercial offices

From April 2023, the minimum EPC rating for let commercial properties is Band E — breaching this means the property is unlettable for new or renewed leases. The government consulted on raising this to Band B by 2030 (currently paused post-2024 election). Office buildings in EPC Bands F and G face immediate lettability risk; those in C and D face medium-term risk if Band B is implemented. Solar, combined with building fabric improvements and LED lighting, is the most cost-effective route to improve non-domestic EPC ratings.

ESOS Phase 3 deadline (December 2023 — grace period extended)

Energy Savings Opportunity Scheme (ESOS) Phase 3 required qualifying organisations (those with 250+ employees or €50m+ turnover) to submit ESOS compliance notifications by December 2023. ESOS audits identify energy-saving opportunities — solar PV typically appears as one of the highest-NPV recommendations in ESOS audit reports. Non-compliant organisations faced FCA-level financial penalty. Phase 4 is expected in 2027.

SECR reporting and solar

Quoted companies, large unquoted companies, and large LLPs must include energy consumption and greenhouse gas emissions in their annual reports (SECR). Solar installation directly reduces the Scope 2 emissions disclosed in SECR reporting — reducing the disclosed carbon footprint without requiring REGOs (Renewable Energy Guarantees of Origin), since the electricity is self-consumed from physically onsite generation. This is a more robust sustainability claim than purchasing REGOs from the grid.

EPC improvement through solar: what to expect

Non-domestic EPC ratings are calculated using SBEM (Simplified Building Energy Model), which models the building's theoretical energy use. Solar PV is credited in the carbon-based metric (kg CO2/m²/year), not directly in energy use — the improvement depends on the building's baseline carbon factor.

System size	Building size	Typical EPC improvement	Likely band change
30kWp	1,500m²	8–15 points	D→C or C→B in some cases
100kWp	4,000m²	12–20 points	Typically one EPC band (e.g., D→C or C→B)
250kWp	8,000m²	15–25 points	One to two EPC bands
500kWp	15,000m²	18–30 points	One to two EPC bands

EPC improvement of one full band (e.g., Band D to Band C) is achievable on many mid-size office buildings with 100–200kWp solar, LED lighting, and improved HVAC controls. Engaging an SBEM assessor early in project development — before committing to a solar specification — allows the system size to be optimised for the EPC improvement target.

Multi-tenant office: landlord-tenant solar split

The central challenge for multi-let offices is allocating solar generation benefit between the landlord's service charge and individual tenants. Several models have emerged:

Common areas only (simplest)

Solar powers common areas (corridors, lifts, landlord-managed services) only. Landlord benefits directly; tenants benefit indirectly through lower service charge. Simple to implement — no sub-metering or tenant contracts required. Typical self-consumption 40–55% of total generation.

Virtual net metering (split metering)

Solar generation is first allocated to the building common load; excess is distributed proportionally across tenant meters via a Virtual Net Metering arrangement (enabled by smart metering and energy management software). Each tenant's electricity cost is reduced proportionally to their share of common area load. Technically more complex but distributes benefit fairly.

Green Power Sharing Agreement

A formal agreement (similar to a mini-PPA) between the landlord and each tenant specifies the tenant's entitlement to solar generation, the price, and metering arrangements. RICS Green Lease Toolkit templates cover this. Most appropriate for anchor tenants occupying 30%+ of the building.

Project profile in the offices sector?

We model the relevant structures against your specific numbers — postcode, half-hourly demand, accounting position, organisation type. Five working days from enquiry to indicative comparison.

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