Solar PPA vs Buying Outright for Business

Two routes dominate commercial solar funding, and they sit at opposite ends of the risk and reward scale. Buy the system outright and you own the asset, claim the tax relief and keep every pound of saving. Sign a power purchase agreement (PPA) and a third party pays for, owns and maintains the system on your roof while you simply buy the electricity it generates, usually below grid price. This guide compares the two head to head on upfront cost, ownership, tax relief and lifetime return so you can decide which fits your balance sheet.

The two routes at a glance

A capital purchase means you fund the installation from cash or reserves and own everything from day one. A PPA is an off balance sheet arrangement: the funder installs at no cost to you and sells you the output under a long contract, typically 15 to 25 years, at an agreed rate per kWh.

Factor	Buy outright	Solar PPA
Upfront cost	Full system cost from capital	Nil
Who owns the system	You	The PPA provider
Who maintains it	You (or a service contract)	The provider
What you pay	One capital sum	A rate per kWh for power used
Tax relief	You claim it	The provider claims it
Lifetime return	Highest	Lower, but no capital at risk
Balance sheet	Asset on your books	Off balance sheet

Neither is automatically better. The right answer depends on your available capital, tax position, appetite for ownership and how long you plan to occupy the building.

Upfront cost

This is the clearest difference. Buying outright commits capital now, so you carry the full system cost before a single unit is generated. A PPA removes that barrier entirely: the provider funds the build, so your outlay is zero and you begin saving from switch on. That is why PPAs appeal to organisations that would rather deploy cash elsewhere, or that cannot get sign off for a large capital project.

If cash is the obstacle but you still want ownership, there is a middle ground. Hire purchase and asset finance spread the cost over a fixed term while you keep the asset and the tax relief. It is worth comparing these against a PPA before you decide, because a financed purchase often beats a PPA over the full lifetime. See the routes side by side on our finance options compared page.

Ownership and control

When you buy, the system is yours. You decide on battery storage, future expansion, when to service it and what happens at end of contract. You also capture any rise in grid prices as a growing saving, because your generation cost is fixed.

Under a PPA the provider owns the hardware for the length of the agreement. You get predictable power at a set rate, but you do not control the asset, and the contract binds the building for a long period. That matters if you might sell or vacate the premises, because the PPA has to be assigned to the new occupier. Read the exit, buyout and assignment clauses carefully before signing.

Tax relief and the balance sheet

Tax is where outright purchase pulls ahead, and it is worth getting the detail right.

Commercial solar PV is classed as special rate plant and machinery. That has two consequences. It does not qualify for 100% full expensing (that is main rate only), and it does not qualify for the new 40% first year allowance. However, it does qualify for the Annual Investment Allowance (AIA), which gives 100% first year relief on up to £1m of qualifying spend. Because the AIA cap comfortably covers most commercial installs, the majority of buyers can write off the whole cost against taxable profits in year one.

Above the £1m cap, companies can use the 50% special rate first year allowance on the excess, with the remaining balance written down at 6% a year on the reducing balance. VAT on commercial solar is charged at 20% and is reclaimable by VAT registered businesses, so the 0% domestic rate does not apply here.

Two further points help the return on an owned system. Rooftop solar generating power for your own use is 100% exempt from business rates in England from April 2022 to March 2035. And exported electricity earns income under the Smart Export Guarantee (SEG), which replaced the Feed in Tariff and covers systems up to 5 MW.

Under a PPA you claim none of this. The provider owns the asset, so the provider takes the capital allowances, reclaims the VAT and keeps the SEG income. Your benefit is limited to the discount on the power you buy. This is general information, not tax advice, so confirm your own position with your accountant before you commit.

Lifetime return

Over 25 years an owned system almost always returns more, because after the payback period every unit generated is close to free. You have absorbed the cost, claimed the relief and, from that point on, your electricity is priced at little more than maintenance. A typical commercial payback lands in the region of 4 to 8 years depending on system size, energy use and roof, after which the savings run for the remaining life of the panels.

A PPA smooths this into a steady, lower saving with no capital at risk. You never reach the point of near free power, because you are always paying the provider a per kWh rate, and the provider keeps the surplus. The trade off is simplicity and zero outlay against a lower total gain. To model both on your own numbers, use our finance calculator and check the outcome against our payback and ROI guidance.

So which route fits your business

Buy outright, or finance the purchase through hire purchase or a business solar loan, if you have or can raise the capital, want the tax relief and plan to stay in the building. You keep the asset and the full lifetime return.

Choose a power purchase agreement if protecting cash flow matters more than owning the asset, or if a capital project simply will not get approved. You trade some lifetime value for a zero upfront, off balance sheet solution with maintenance included.

For many businesses the strongest option sits between the two: a financed capital purchase that keeps ownership and tax relief while spreading the cost. The only reliable way to know is to compare real numbers for your site.

Get costed quotes

We are a comparison and quote service, not a lender or financial adviser. We connect UK businesses with vetted MCS certified installers and funders, then bring back costed quotes across every route so you can compare like for like. Tell us about your building and usage on our quote page, and see indicative pricing first on our cost guide. A ten minute enquiry is enough to see whether buying, financing or a PPA gives your business the best return.