How to write the board business case for office solar

What boards actually want to see

Office solar proposals fail at board level more often through poor business case framing than through bad project economics. After supporting 40+ commercial solar capex papers through to board approval, four framing elements consistently determine outcomes.

1. NPV over 25 years, not simple payback

Simple payback (capex / annual saving) is a finance director’s first metric but rarely the deciding one. Boards comparing solar capex against other investments want NPV at the company’s WACC, IRR, and a risk-adjusted ROI.

Typical UK office solar at 5-6 year payback delivers 25-year NPV of 5-7× the capex outlay at 7-10% WACC. That framing — “for every £1 we invest, we get back £6 over 25 years discounted to present value” — is more compelling than “5 year payback.”

2. Cash-flow profile, not just headline returns

Boards considering capex want to understand cash-flow shape over time. For solar:

Year 0: capex outflow
Year 1: AIA tax saving (25% of capex for limited companies)
Years 1-25: annual savings flow (££/year)
Year 12-15: inverter replacement (£35-60/kW)
Year 25-30: panel performance below economic threshold

The cash-flow profile is unusual among capex investments because of the large year-one tax benefit (AIA) and the very long tail of positive cash flows.

3. Risk-adjusted decision framing

Solar PV has lower technical risk than most major capex investments — it’s well-understood technology with 30-year operating histories. But boards want to understand specific risks:

Grid price risk. What if electricity prices fall? Below ~18p/kWh blended retail, project NPV starts to degrade.
Self-consumption risk. What if building occupancy patterns change (more hybrid working, building disposal)? Self-consumption falls but SEG revenue rises partially compensating.
MEES compliance risk. What if EPC re-rating doesn’t deliver predicted uplift? Typically captures 60-90% of modelled gain even in adverse cases.
Tenant change risk (for landlord installs). What if a major tenant departs? Service-charge recovery proportion may fall.
Technology obsolescence risk. What if panels become dramatically cheaper in 10 years? The installed system continues delivering its modelled value; new technology doesn’t make existing systems worse.

4. Strategic ESG framing

Boards approving solar capex are increasingly looking at it as a multi-factor decision: financial return + ESG positioning + MEES regulatory compliance + tenant proposition + employer brand. The financial case stands on its own merit, but the strategic case multiplies it.

For multi-let landlords specifically, the MEES 2030 framing is now the dominant driver: “this is mandatory regulatory compliance with a positive NPV” is a much stronger board proposition than “this is voluntary capex with positive NPV.”

The 6-page template

A workable board paper structure that consistently wins approval:

Page 1: Executive summary (1 page)

Investment ask (£)
Financial summary (NPV, IRR, payback, year-one cash impact)
Strategic rationale (1 paragraph)
Recommendation (specific board decision required)

Page 2: Project overview (1 page)

System specification (kWp, panels, inverters, battery)
Site description
Programme (key dates, dependencies)
Technical risk summary

Page 3-4: Financial analysis (2 pages)

Capex breakdown
Annual cash flow projection (25 years)
NPV at WACC sensitivity
IRR
Comparison with alternative capex priorities
Funding route recommendation

Page 5: Strategic and risk (1 page)

ESG positioning impact (Scope 2 reduction, SECR/TCFD/CDP)
MEES 2030 compliance positioning
Tenant proposition impact (multi-let) or recruitment impact (single-occupier)
Key risks and mitigations
Sensitivity to electricity price assumptions

Page 6: Decision and next steps (1 page)

Specific board decision required
Approvals required (sub-committee, audit, environmental)
Programme to commissioning
Reporting cadence

What we provide

For every office solar proposal, we provide:

Board-paper-ready executive summary text
25-year cash flow projection (Excel + summary table)
NPV at user-defined WACC
All four funding route comparisons
ESG documentation pack draft
Risk register
Programme

The materials are designed to drop into a board paper with minimal additional work — typically saving 20-40 hours of finance team time.

Request a feasibility study with board-paper-ready materials.