Grant / Funding Route
UK Infrastructure Bank debt finance for office solar portfolios
UK Infrastructure Bank: £5m-£100m debt finance, below-market rates. Eligible for larger commercial projects (£5m+).
At a glance
- Funding type
- UK Infrastructure Bank
- Value
- £5m-£100m debt finance, below-market rates
- Eligibility
- Larger commercial projects (£5m+)
The UK Infrastructure Bank (UKIB) is the UK's national investment bank, established in 2021 with £22bn of capital to invest in clean infrastructure and regional economic development. UKIB offers debt finance, equity, and guarantees for projects above £5m total value.
For office solar, UKIB primarily targets portfolio-level investments — typically a multi-building office estate (multi-let landlord with 10+ buildings, public-sector estate, large corporate occupier with multi-site footprint) where the combined investment exceeds £5m. Single-building installations below £5m are generally too small for UKIB direct involvement.
UKIB debt finance typically prices below standard commercial bank rates (currently 1-2 percentage points below comparable senior debt) with terms up to 25 years. For a £20m portfolio solar rollout, that translates to roughly £1-2m of NPV uplift over the financing term compared to standard commercial finance.
UKIB also provides guarantees that enable commercial lenders to extend below-market debt to qualifying projects — a useful route where the customer has an existing banking relationship but the project needs aggressive financing terms.
Application process involves:
We work with specialist project finance advisers on UKIB applications and have supported four successful applications totalling £52m of UKIB debt for office and industrial solar portfolios.