Solar PV Business Case Template UK 2026

UK finance directors and CFOs writing solar PV business cases for board approval need more than a quote — they need a board-paper-grade financial analysis that stands up to scrutiny against alternative capex investments. This page is the 10-section business case template used by our enterprise clients across UK SME, mid-market, and industrial commercial solar projects. Each section has a defined purpose, target length, and required content. For the underlying financial calculations see our savings calculator; for our complete buyer\'s guide see commercial solar buyer\'s guide 2026.

The 10-section business case template

Section 1: Executive Summary (1 page max)

The single most important page in the business case. Board members read this first and often only. Required content: (1) Recommendation — clear "approve" / "approve subject to conditions" / "defer" recommendation in the opening line. (2) Project headline — system size kW + capex £ + payback years + 25-year NPV £. (3) Strategic alignment — 1-2 sentences on how solar fits company strategy (Scope 2 commitments, electricity cost management, customer ESG requirements, supply chain decarbonisation). (4) Financial summary table — capex, AIA tax relief, year-1 savings, simple payback, IRR, NPV. (5) Approval request — capex authorisation amount + payment schedule + named approver.

Section 2: Strategic Rationale (2 pages)

Answers the "why now" question. The 5 strongest 2026 strategic arguments. (1) Electricity inflation hedge. UK commercial grid electricity inflated 8-12%/year compound 2020-2025. Solar locks in 25-year electricity cost at 4-7p/kWh LCOE vs 24-32p/kWh grid retail — material inflation protection unavailable from any grid procurement strategy. (2) Scope 2 emissions reduction. Mandatory disclosure for major UK suppliers via supply chain pressure (Tesco, Unilever, BMW, IKEA, Microsoft, Google, Amazon mandating supplier Scope 2 evidence). Solar reduces Scope 2 by 30-70% at typical SME. (3) Customer + investor ESG expectations. SBTi (Science-Based Targets initiative) commitments now mainstream across UK PLC + mid-market. (4) Supply chain CBAM. EU Carbon Border Adjustment Mechanism phases in fully from 2026, charging carbon at the EU border on UK exports of cement, steel, aluminium, fertiliser, hydrogen, electricity. Solar self-consumption directly reduces CBAM exposure. (5) MEES compliance preparation. Minimum Energy Efficiency Standards tightening 2030 — solar contributes to EPC rating uplift.

Section 3: Project Description (1 page)

Concise project specification. Required content: system size in kW + number of panels + module brand + inverter brand + mounting type + roof or ground location, target install location with address, target install timeline (contract → commissioning), key technology choices (justification for module + inverter brand selection), capex range with itemised cost breakdown reference (full itemisation in Section 4). Include 1-2 reference images or layout diagrams where useful for board comprehension. Avoid technical depth at this stage — that\'s for the implementation plan.

Section 4: Financial Analysis (3-4 pages)

The heart of the business case. Required content: Full 25-year DCF model summary table showing capex (gross + AIA-adjusted net), operating costs (maintenance, inverter replacement Y12-15, insurance), electricity savings (avoided import × self-consumption ratio), SEG export income, net annual cash flow, discounted cash flow at 7% rate, cumulative NPV. 4-metric headline output: simple payback gross + AIA-adjusted, discounted payback, IRR, NPV at 7%. Underlying assumptions table: system size, annual generation (P50), self-consumption ratio, electricity import tariff, SEG export rate, electricity inflation rate, panel degradation rate, discount rate, AIA tax relief rate. Comparison to alternative capex uses — IRR comparison to corporate bonds, property investment, equipment leasing, business reinvestment. Cash flow profile chart showing payback crossover year and 25-year cumulative.

Section 5: Sensitivity Analysis (2 pages)

Stress-test the central case. Required content: Single-variable sensitivity table showing NPV impact of varying each key variable (electricity inflation, self-consumption, generation P50 vs P90, capex ±10%, exit horizon 10/15/20/25 years). Tornado chart visualising the relative impact of each variable. Multi-variable scenario analysis — best case (high inflation + high SC + P50), central case, worst case (low inflation + low SC + P90 - 10% capex variance). Conclusion paragraph noting which variables dominate NPV variability and which the project is robust against. Board members particularly value evidence the recommendation holds across reasonable downside scenarios.

Section 6: Finance Route Comparison (2 pages)

Side-by-side comparison of all four finance routes. Required content: 4-column table comparing Cash + AIA / Asset Finance / Operating Lease / PPA across year-1 cash impact, 25-year NPV, IRR, balance sheet treatment, tax treatment, ownership at end of term, performance risk transfer, exit/sale handling. Recommendation paragraph stating which route fits the company\'s specific capital structure, tax position, balance sheet preferences, and risk appetite. Indicative term sheet for the recommended route — for asset finance: lender, term, rate, monthly payment, total cost of credit. See our PPA vs cash purchase comparison for the underlying analysis framework.

Section 7: Risk Assessment (2 pages)

Comprehensive risk register. Required content: Risk register table with 8-12 identified risks across 5 categories (performance, counterparty, regulatory, technology, exit). For each risk: description, probability (H/M/L), impact (H/M/L), inherent risk score, mitigation strategy, residual risk score, owner. Top-3 risk narrative describing the most material risks and how the project mitigates each. Insurance position — confirmation of public liability (£5m+), professional indemnity (£5m+), workmanship warranty insurance backing, manufacturer warranties. Force majeure provisions if relevant (extreme weather, supply chain disruption).

Section 8: ESG + Strategic Benefits (2 pages)

Quantified ESG impact. Required content: Scope 2 emissions reduction — tonnes CO2 saved annually + 25-year lifecycle (typical 100 kW system: 22 tCO2/year × 25 years = 480-560 tCO2 lifecycle). Carbon intensity reduction — gCO2/kWh before vs after solar install. SBTi alignment — confirmation that solar contributes to Science-Based Target trajectory. Customer ESG reporting impact — qualitative + quantitative effect on ESG disclosures to key customers. Supply chain CBAM hedging for EU exporters of cement, steel, aluminium, fertiliser, hydrogen, electricity. EPC rating impact — typical 1-2 grade uplift, valuable for MEES 2030 compliance. Strategic optionality — solar enables future EV fleet charging, heat pump replacement, battery storage addition.

Section 9: Implementation Plan (1 page)

Project execution framework. Required content: 10-stage Gantt chart from contract to commissioning (use our installation process 10-stage framework). Named project sponsor + named project manager + named steering group attendees. Governance cadence — monthly steering group, weekly PM updates. Milestone payment schedule — typically 30/30/30/10. Go/no-go decision points — 4 decisions across the lifecycle. Key dependencies — DNO approval, planning permission (if applicable), capex committee approval cycle.

Section 10: Recommendation + Approval Request (1 page)

The formal ask. Required content: Recommended decision — "approve" / "approve subject to [conditions]" / "defer pending [further analysis]". Capex authorisation request — total amount + payment schedule + reserve for contingency. Named approver — board member, CFO, or designated approval authority depending on internal limits. Conditions precedent if any (e.g. final lender term sheet, DNO connection offer confirmation, planning permission approval). Decision deadline — to maintain quote validity (typically 30 days from quote date). Sign-off block for formal board approval recording.

Worked example: 100 kW SME business case headline numbers

Reference numbers for a typical 100 kW UK SME commercial solar business case. Project: 100 kW PV system on 1,500 sqm office building, Birmingham, 60 staff, 100,000 kWh annual demand, 27p/kWh current tariff, 75% self-consumption ratio. Capex: £100,000 gross, £75,000 net of 100% AIA tax relief. Year-1 savings: £20,250 (£18,225 avoided import + £2,025 SEG export). Simple payback: 4.9 years gross, 3.7 years net AIA. Discounted payback (7%): 6.2 years gross. IRR: 19.7% net AIA. NPV 25-year @ 7%: £232,000. Scope 2 reduction: 22 tCO2/year (480 tCO2 lifecycle). Sensitivity range: NPV £155k worst case (3% inflation + P90 + 65% SC) to £335k best case (5% inflation + P50 + 90% SC). Recommendation: approve £100,000 capex authorisation, asset finance route preferred (7-year term, monthly payment £1,420 vs monthly savings £1,690 = cash-flow positive year 1).

How to get the underlying numbers for your specific business case

The template structure on this page is one half of the picture. The other half is the site-specific underlying numbers — capex, generation, self-consumption, payback. Our free 5-working-day desk feasibility provides all the underlying numbers you need to populate the template for your specific business. You receive: PVSyst yield model with P50/P90 estimates, indicative capex with 12-item itemisation, AIA-adjusted financial analysis, 4-route finance comparison, DNO constraints check, sector-specific load profile modelling. From there, your finance team wraps the numbers in the narrative for your specific board.