Tools and guides for commercial solar finance.
Calculators, comparison tables, and explainers — the technical detail behind the structures we recommend.
UK commercial solar finance resources — calculator, glossary, planning tools
This resources hub collects 11 working tools, technical guides, and planning materials supporting UK commercial solar finance decisions. The interactive calculator handles capital purchase, green loan, finance lease, operating lease, and PPA comparison with battery storage and AIA toggle options. The 91-term glossary covers UK tax allowances, finance structures, technical specifications, and ESG reporting frameworks. Specialist guides cover half-hourly demand sizing, FYA deadline planning, Scope 2 emissions reduction, G99 grid connection, DNO export limits, structural roof assessment, and half-hourly data acquisition.
Most UK commercial solar projects benefit from working through these resources during initial scoping rather than relying on installer-provided materials. The interactive calculator runs the same finance structure comparison we apply in formal advisory engagements, with battery storage and AIA tax route options that reflect 2026 UK conditions accurately. The half-hourly sizing guide explains why typical installer rule-of-thumb sizing (60% of annual consumption) systematically under- or over-sizes industrial, refrigeration, and seasonal businesses by 20-40%.
For projects approaching 31 March 2026 FYA deadline, the FYA deadline calendar provides month-by-month planning guidance. For projects considering battery storage alongside solar, the battery economics insight piece works through the four scenarios where battery adds material value (export-constrained sites, time-of-use exposure, capacity market access, resilience-critical operations). For ESG-driven buyers, the Scope 2 reduction guide covers TCFD, SECR, CDP, SBTi, and RE100 alignment.
All resources here are open-access and free. Where projects move to formal advisory engagement, we provide bespoke modelling, lender shortlisting, and contract negotiation alongside the resources here. Contact us if any specific tool or guide doesn't answer your question.
Interactive Calculator
Compare capital purchase, green loan, finance lease, operating lease, and PPA on your project numbers. Year 1 cash position, 25-year cumulative, and simple payback — updates live.
Solar payback calculator
How to calculate commercial solar payback properly — inputs, common errors, realistic 2026 ranges.
Half-hourly sizing guide
Why annual consumption misleads, how to obtain HH data, the modelling approach, and a worked example showing 4-point IRR uplift from correct sizing.
FYA deadline calendar
Month-by-month planning calendar for capturing the 50% FYA before the 31 March 2026 deadline. Lead times by project size; recommended order timing; post-deadline scenario.
Scope 2 reduction guide
Working guide to UK commercial solar PV for Scope 2 emissions reduction, ESG reporting frameworks, and customer-side procurement requirements.
G99 commercial solar connection
Comprehensive guide to the G99 grid-connection process for commercial solar above 50 kW — application steps, study windows, reinforcement triggers, typical timelines.
DNO export limits
When DNO export consent becomes the binding constraint on commercial solar sizing. Understanding ANM, curtailment risk, and battery-storage workarounds.
Commercial solar roof structural assessment
When and why structural surveys are required, what they cost, what they typically find, and how to budget for reinforcement on older commercial roofs.
Half-hourly data acquisition guide
How to obtain half-hourly electricity demand data from your supplier, alternative metering routes for non-HH-settled sites, and how the data feeds optimal solar sizing.
Glossary
UK commercial solar finance terminology — capital allowances, finance structures, tax incentives, technical standards, ESG reporting, property considerations.
Finance comparison table
Six finance structures modelled against the same £200k 250kWp project. IRR, year-one cash, 25-year cumulative.
Technical and financial tools for commercial solar decisions
Our resource library provides commercial solar decision-makers with the technical guides, financial calculators, and reference tools needed to evaluate, plan, and manage solar installations with confidence. Each resource is UK-specific, current, and written for the practitioner — finance director, energy manager, or estate manager — not the general reader.
Financial decision tools
Finance product comparison
Structured comparison of all UK commercial solar finance products — green loan, hire purchase, operating lease, finance lease, PPA, PSDS grant, SALIX loan — across the dimensions that matter: ownership, balance sheet treatment, AIA eligibility, typical rates, and best-fit scenarios.
Interactive payback calculator
Calculate payback period and 20-year ROI for any commercial solar installation. Inputs include system size, UK location (for irradiation data), finance type, current electricity tariff, and estimated self-consumption ratio. Results show cash flow by year.
CapEx vs PPA decision tree
A structured decision framework that guides you to the right finance structure for your specific situation — incorporating property ownership, credit profile, tax position, cash availability, and long-term goals.
AIA vs FYA detailed comparison
When Annual Investment Allowance (100% first year, up to £1m) and 50% First Year Allowance each apply, with worked examples across system sizes. Covers group company AIA sharing rules and year-end timing strategies.
Technical reference guides
G99 commercial solar connection
Complete guide to the G99 DNO connection process for systems above 50kWp: pre-application enquiry, formal application submission, technical assessment, protection relay requirements, commissioning, and timeline management.
DNO export limits explained
How distribution network operators set export limits, which networks have constrained capacity, and how to manage limits through battery storage, demand shifting, or active power control systems.
Roof structural assessment guide
Why structural assessments are required for all commercial solar, what they cover, typical costs (£1,500–5,000), common roof type issues, and how to manage reinforcement works if needed.
Half-hourly data acquisition
How to access SMETS2 half-hourly smart meter data, what it shows, and how to use it for solar system sizing, SEG tariff selection, and battery dispatch optimisation.
Half-hourly system sizing guide
Why half-hourly demand data produces more accurate solar system sizing than monthly averages — and how to use it to avoid under- or over-sizing your commercial installation.
Scope 2 emissions reduction guide
How commercial solar reduces Scope 2 (purchased electricity) emissions, how to calculate and verify the reduction, and how to report it under GHG Protocol, CDP, and TCFD frameworks.
Using the resource library
Start with the finance comparison and payback calculator to establish your project business case. Use the decision tree to confirm your finance structure. Then use the technical guides to plan installation logistics and manage the application processes that run on your critical path.
Resources are updated regularly to reflect HMRC Capital Allowances changes, DNO process updates, and SEG market developments. For personalised guidance on a specific project, contact our specialist team.