Funding options for UK clean tech and circular economy businesses

Funding clean tech businesses in the UK remains a stage-by-stage problem. The mix of grants, tax reliefs, and equity that works for a software platform looks nothing like the mix for a battery recycling plant, and what works at seed stage rarely fits at Series A. Where these funding routes interact, the accounting determines whether the business captures every pound of available relief.

Pre-seed and seed: SEIS, angels, and feasibility grants

Most clean tech businesses start with a combination of angel investment and early-stage grants. Two schemes shape how angel capital flows into UK start-ups.

The Seed Enterprise Investment Scheme (SEIS) offers investors 50% income tax relief on investments up to £200,000 per tax year. The company can raise up to £250,000 lifetime under SEIS. For investors, the scheme also provides CGT exemption on shares held for three or more years. Over 10,000 investors used SEIS in the 2023-24 tax year.

Advance Assurance from HMRC confirms that a company qualifies before investors commit. Around two-thirds of angel investors will not invest without it. Getting Advance Assurance in place before approaching investors, not during negotiations, removes a common sticking point. The application itself takes two to four weeks to prepare and HMRC typically responds within 28 days.

At this stage, Innovate UK feasibility grants can cover up to 70% of project costs for SMEs. The grant amount is modest, but the signal is not. Investors treat Innovate UK funding as independent technology validation. A company that has won competitive grant funding has already survived external due diligence on its technical approach.

Where the technology originates from university research, Innovate UK’s ICURe programme and university-backed spinout funds can help bridge the gap between academic research and company formation.

What changes between seed and Series A

The Enterprise Investment Scheme (EIS) takes over where SEIS reaches its limits. EIS provides 30% income tax relief for investors, with individual investment up to £1 million per tax year. The company must be under seven years from first commercial sale, with fewer than 250 employees and gross assets below £30 million. From April 2026, the annual company raising limit doubled to £10 million and the lifetime limit to £24 million.

Many clean tech businesses qualify for Knowledge-Intensive Company (KIC) status without realising it. KIC extends the EIS limits to £20 million per year and £40 million over a company’s lifetime, with the employee threshold rising to 500. A company qualifies if it spends at least 15% of operating costs on R&D in each of the three preceding years (or 10% over ten years), and holds qualifying intellectual property or employs a sufficient proportion of staff with advanced degrees. For capital-intensive clean tech firms burning through R&D spend at a high rate, meeting the threshold is straightforward.

Innovate UK’s Growth Catalyst pilot targets clean energy and climate tech businesses between seed and Series A. It provides grant funding covering up to 70% of project costs, with a requirement for aligned private equity at a minimum of 2x the grant value. The grant-plus-equity structure moves a company from funded R&D to a position that private investors will back.

Innovation Loans offer between £100,000 and £2 million in repayable, non-dilutive funding. Most applicants do not pass the commercial viability testing, so these suit businesses with a clear route to revenue and a sound financial model rather than pure R&D-stage companies.

Series A and beyond: scaling the funding stack

EIS with KIC limits remains available at Series A for qualifying companies. Beyond EIS, three public funding routes become relevant.

For hardware-heavy clean tech companies building first-of-a-kind production plants, the National Wealth Fund provides patient capital at a stage where private venture capital may not fit.

It is worth noting that where a business is directly involved in energy generation, it may fall within HMRC’s definition of excluded activities for EIS purposes. At this stage, funding is often structured outside of EIS, with a greater reliance on institutional or public capital.

Access to EU collaborative research funding reopened in January 2024 through full association with Horizon Europe. For clean tech companies with European research partners or supply chains, Horizon grants can fund multi-year R&D programmes. Debt and equity finance is also available through British Business Bank programmes via accredited intermediaries, supporting clean tech-focused venture funds and lending programmes.

Capital expenditure: where allowances fit in

At the point where a clean tech business is investing in production equipment, facilities, or infrastructure, capital allowances reduce the effective cost. The Annual Investment Allowance (AIA) provides 100% deduction on the first £1 million of qualifying plant and machinery spend per year. Above that, the treatment depends on whether assets are classified as main rate (100% full expensing) or special rate (50% partial expensing in year one).

The distinction matters. On a £3 million capital programme, the difference between main rate and special rate classification is a significant cash timing issue. We cover the full breakdown, including the new 40% first-year allowance for leased assets and the April 2026 WDA rate change, in our article on tax reliefs beyond R&D.

The Series B gap

UK clean tech businesses face a structural funding challenge at Series B. The amounts required for first production plants or commercial-scale facilities, often £10 million to £50 million, exceed the appetite of most venture capital funds while arriving too early for project finance or infrastructure investors who want proven cash flows.

The gap exists because of market structure, not company quality. The National Wealth Fund is intended to provide patient capital in this space. Green bonds and project finance become viable once a business can demonstrate revenue or contracted offtake. Between Series A and that point, many clean tech companies face a constrained set of options.

Closing the gap usually means combining grant funding, retained R&D tax credits, strategic corporate investment, and long-term equity. Each investor type needs a different financial model.

How funding routes interact for clean tech businesses in the UK

Stacking multiple funding sources is standard practice for clean tech businesses. A single company might hold SEIS equity, an Innovate UK grant, R&D tax credits, and capital allowances simultaneously. The interactions between these need active management.

Since April 2024, grant-funded R&D qualifies for R&D tax relief on the same basis as self-funded expenditure (see our R&D tax relief articlefor the full breakdown). Businesses that previously may have needed to make RDEC claims in respect of Innovate UK-funded work, should revisit their position.

The position is different for capital allowances. If a business receives a £200,000 grant towards a £500,000 piece of qualifying equipment, the capital allowance claim is based on the net £300,000 spend. Getting this accounting wrong means either overclaiming, which creates compliance risk, or underclaiming, which leaves money unclaimed.

R&D tax credits and capital allowances operate through different systems. The R&D expenditure credit covers revenue expenditure on qualifying R&D. Capital spend on R&D equipment is claimed through the 100% Research and Development Allowance instead. Confusing the two routes means misallocating costs between claims.

A company that claims full capital allowances on grant-funded equipment and then faces an HMRC review will spend more correcting the position than it would have spent getting the allocation right at the outset.

The accountant’s role at each stage

Investors expect SEIS Advance Assurance and a clean corporate structure before they write a cheque. These are pre-seed priorities.

The requirements shift at the first institutional round. Grant accounting, R&D claim preparation, and financial modelling for investor presentations become the focus. The quality of a company’s financial reporting directly affects investor confidence, particularly when the business is pre-revenue and the financial model must compensate for the absence of revenue data.

After Series A, the priority moves to scenario planning: modelling how different combinations of grants, equity, tax credits, and capital allowances affect runway and dilution. On a multi-million pound capital programme, the gap between the right and wrong structure can be worth hundreds of thousands in relief.

How Wilson Partners can help

Wilson Partners advises clean tech and circular economy businesses on funding strategy from pre-seed through to production-scale investment. Whether you need SEIS Advance Assurance, capital allowances modelling, or a view on how your funding sources interact, our advisory team can map the right structure for your stage. Get in touch.

Frequently asked questions

Can my clean tech business receive grant funding and still claim R&D tax relief on the same expenditure?

Yes. From April 2024, grant-funded R&D qualifies for relief under both the merged R&D scheme and Enhanced R&D Intensive Support (ERIS). The subsidised expenditure rules that previously restricted this were removed.

What is the difference between SEIS and EIS for clean tech investors?

SEIS offers 50% income tax relief on investments up to £200,000, with a £250,000 lifetime company limit. EIS offers 30% relief on investments up to £1 million, with a company lifetime limit of £24 million from April 2026. SEIS is for very early-stage companies. EIS covers later rounds and larger raises. Both provide CGT exemption on shares held for three years or more.

What is the Series B gap and why does it affect clean tech businesses?

The Series B gap describes the funding shortfall between venture capital rounds and project finance. Clean tech businesses often need £10 million or more for first production facilities, but at a stage where revenue is unproven. Most VC funds cannot write cheques at this scale for pre-revenue hardware, and project finance requires demonstrated cash flows.

Do grants reduce the amount I can claim in capital allowances?

Yes. Grant funding received towards a capital asset reduces the qualifying expenditure for capital allowances on a pound-for-pound basis. A £500,000 asset funded by a £200,000 grant would generate a capital allowance claim based on £300,000 net spend.

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