PPA vs Asset Finance vs Buying: How to Fund Business Renewables

How to fund business renewable energy: the three real options

When a board asks how to fund business renewable energy, the honest answer is that the technology is rarely the hard part. Solar PV, battery storage, heat pumps and EV charging are all mature and bankable. The question that stalls most projects is who pays for the kit, when, and who owns it afterwards. Get the funding structure right and a renewable project pays for itself. Get it wrong and you either tie up capital you needed elsewhere, or lock into a contract that quietly erodes the savings.

There are three main routes: cash purchase, asset finance, and a Power Purchase Agreement (PPA). Each suits a different balance sheet, a different appetite for control, and a different carbon story. Below is an honest comparison, with the real UK tax reliefs and grants that change the maths, so you can take a defensible recommendation to your finance director rather than a sales pitch.

Option one: buying outright (cash purchase)

Buying the system outright gives you the lowest lifetime cost and full ownership of every kilowatt-hour it generates. For a profitable, cash-rich business this is usually the cheapest way to own commercial solar, and it is what most of our clients end up doing once the numbers are on the table.

The reason is tax. Solar PV, batteries, EV chargepoints and heat pumps all qualify as plant and machinery, so the full capital cost can be deducted from taxable profit in year one under the 100% Annual Investment Allowance (up to the £1m cap), or under Full Expensing for larger companies above it. In practice a profitable company recovers roughly 25% of the cost through corporation tax, and VAT-registered businesses reclaim the VAT on top. A commercial solar array priced at, say, £600 to £1,300 per kWp before relief has a materially lower effective net cost once AIA is applied.

Cash purchase also delivers the strongest payback: commercial solar typically returns in 5-8 years and then produces 15-20 years of near-free power under a 25-year warranty. The trade-off is the upfront outlay and the opportunity cost of that capital. If the same money would earn more deployed in the core business, one of the funded routes below may serve you better even though the headline cost is higher.

Option two: asset finance (spread the cost)

Asset finance, usually a lease or a hire-purchase agreement, spreads the cost of the system over five to seven years while you take the energy savings from day one. Because the monthly saving on your electricity bill often exceeds the monthly finance payment, a well-structured deal is cash-flow positive from month one. You are, in effect, paying for the system out of money you were already handing to your energy supplier.

This is the route that answers the most common objection we hear, that a business cannot justify a large capex project right now. It keeps cash on the balance sheet for the core business, and depending on the agreement structure you may still access capital allowances on a hire-purchase deal (your accountant should confirm the treatment for your specific contract). It works well for EV charging and battery storage as well as solar, and it can be layered so each measure in your roadmap is funded as it comes online.

The cost of the finance itself is the trade-off: you pay interest, so lifetime cost sits above a cash purchase. But for many businesses the improvement in cash flow and the ability to act now rather than in three budget cycles outweighs that premium.

Option three: a Power Purchase Agreement (zero capex)

A Power Purchase Agreement removes the capital barrier entirely. Under an on-site PPA, a third-party funder installs and owns generation on your roof, land or car park, and you simply buy the power it produces at a fixed rate below your grid price. There is no upfront cost and no maintenance liability, because the funder owns the asset and keeps it running.

On-site PPA terms typically run 15-25 years with defined buy-out and end-of-term options, so it suits businesses with secure tenure that want clean power and price certainty without owning the kit. Landlords need to review roof or land lease terms and any Minimum Energy Efficiency Standards interactions before signing. For businesses that cannot or will not use their balance sheet, and public bodies and charities in particular, it is often the only route that gets a project built.

There is a second family of PPAs worth knowing. A corporate or sleeved PPA lets you contract clean power from an off-site wind or solar farm at a fixed long-term price, with a licensed supplier “sleeving” the electricity to your meter. This suits businesses whose own site cannot host enough generation but who still want long-term price certainty and a credible carbon claim. Both structures deliver genuine additionality (new generation that would not otherwise exist), which is the auditable ESG claim that REGO-only green tariffs lack. See our PPA and procurement page for how the structures compare in detail.

PPA vs asset finance vs buying, side by side

Factor	Buy outright	Asset finance	On-site PPA
Upfront capital	Full capex	None (deposit possible)	Zero
Who owns the kit	You	You (after term)	The funder
Lifetime cost	Lowest	Medium (interest)	Higher, but no capex
Capital allowances	Yes, 100% AIA	Often, contract-dependent	No (funder claims)
Cash flow	Outlay then savings	Positive from month one	Positive from day one
Typical term	Own the 25-year asset	5-7 years	15-25 years
Best for	Cash-rich, profitable firms	Firms preserving capital	Zero-capex, tenure secure

The right choice is rarely obvious from the headline cost alone. It depends on your tax position, your cost of capital, how long you will occupy the site, and whether ownership matters to you. This is why we model cash purchase, asset finance and PPA side by side for every project, with the internal rate of return and the tonnes of CO2 saved under each, so the decision is made on merit rather than on which product a salesperson happens to offer.

Grants and reliefs that change the maths

Whichever route you choose, layer in the support that applies. Most business support is now delivered through tax relief rather than direct grants, but several schemes still move the numbers:

• 100% Annual Investment Allowance and Full Expensing are the primary lever for owned kit, recovering roughly a quarter of the cost through corporation tax.
• The Workplace Charging Scheme contributes £350 per EV socket for up to 40 sockets, and the EV infrastructure grant adds up to £15,000 toward wiring and groundworks for SMEs.
• The Smart Export Guarantee pays for surplus solar exported to the grid, typically 4-15p/kWh, which matters most for sites that export at weekends or overnight.
• The Industrial Energy Transformation Fund offers grants from £100,000 upward for energy-intensive manufacturers, and the Public Sector Decarbonisation Scheme funds heat pumps and solar for public bodies, schools and the NHS.

One honest note: the domestic Boiler Upgrade Scheme does not apply to commercial buildings, so if you are electrifying heat with commercial heat pumps, the funding routes are capital allowances, PSDS and IETF rather than a per-unit heat-pump grant. Our grants and funding page tracks the current windows, because regional and combined-authority schemes open and close through the year.

Fund the roadmap in the right order

The cheapest project is the one you do not have to fund at all. Before committing capital to generation, cut waste with energy management and efficiency measures. An energy audit plus voltage optimisation, LED lighting and better controls typically removes 8-25% of consumption at a one-to-four year payback, and it means any solar, battery or heat pump you then fund is sized to a lower, well-managed demand rather than paying to generate power you were wasting.

That sequencing keeps the whole programme cash-positive as it grows: efficiency pays fastest, solar next, then storage and electrification of heat and transport funded as each measure earns its return. Because efficiency measures are cheap and quick, many businesses self-fund the first phase from operating budget and reserve finance or a PPA for the larger generation projects that follow.

Getting the numbers for your site

Every figure above is an indicative UK range. The funding route that is right for your business depends on your actual load profile, tax position and tenure, which is why we size and cost every option from your half-hourly meter data rather than roof area or a nameplate figure. Our assessment models cash, finance and PPA side by side with the payback, IRR and carbon outcome of each.

To see how the three routes compare for your building, start with our cost guide for current price ranges across the full stack, then request a free assessment and quote. We will tell you honestly which funding structure stacks up for your site, and which does not.