Capital Purchase (Cash)

Where capital purchase fits

Buying a commercial solar system outright is the simplest funding route to understand and the one that returns the most over the life of the asset. You pay the full installed cost from your own reserves, you own the system from the day it is commissioned, and every unit of value it produces from then on belongs to you. There is no funder sitting between you and the panels, so there is no finance margin to service and no repayment schedule to manage. For a business that holds spare cash and wants the strongest lifetime return, this is usually the benchmark that every other route is measured against.

How it works in practice

The mechanics are deliberately plain. You agree a specification and price with an installer, you pay the installed cost, and the system becomes an asset on your balance sheet. From that point you keep everything it generates: the electricity you self-consume displaces power you would otherwise buy from the grid, and anything you export can earn payments under the Smart Export Guarantee (SEG), which replaced the Feed-in Tariff and covers exported generation up to 5 MW. Because you own the equipment outright, you also control decisions about it. You choose the maintenance provider, you decide when and whether to add battery storage later, and you are free to refinance or sell the asset without a funder's consent.

The counterpart to that control is that you carry the risks too. If a component underperforms or a repair is needed outside warranty, that cost falls to you rather than a lease or PPA provider. A sensible capital purchase is therefore paired with a clear maintenance plan and realistic performance assumptions rather than best-case yield figures.

Who it suits, and who it does not

Capital purchase tends to suit businesses with healthy reserves, a stable trading outlook, and a genuine appetite to hold the asset for the long term. If your working capital is comfortably ahead of what the install costs, and that cash is not earmarked for a higher-return use elsewhere, owning outright will almost always beat a financed route on total lifetime savings.

It suits you less well if the outlay would leave the business short of headroom, if you would rather keep cash available for stock, hiring or expansion, or if you want the maintenance and performance risk sitting with a third party. In those cases a financed route such as hire purchase, a business solar loan, or a fully off-balance-sheet power purchase agreement may fit the way you run the business more comfortably, even though the headline lifetime return is lower.

The tax and accounting angle

The tax treatment is a large part of why buying outright looks so strong on paper. Solar PV is classed as special-rate plant and machinery, so it does not qualify for 100% full expensing (which is main-rate only) or the newer 40% first-year allowance. What it does qualify for is the Annual Investment Allowance (AIA), which gives 100% first-year relief on qualifying spend up to £1 million a year. Because most commercial rooftop installs sit well below that cap, the majority attract full first-year relief on the whole cost.

If your qualifying capital spend for the year exceeds the £1 million AIA cap, the balance attributable to the solar asset can use the 50% special-rate first-year allowance, which is available to companies, with the remaining value then written down at 6% a year on the reducing-balance basis. VAT on commercial solar is charged at the standard 20% rate; the 0% domestic rate does not apply to commercial installs, but a VAT-registered business can normally reclaim that VAT through its return, which reduces the real cost of ownership. On top of this, rooftop solar generating power for your own use is 100% exempt from business rates in England from April 2022 to March 2035, so self-consumption does not increase your rateable value.

This is general information rather than tax advice. Allowances, VAT recovery and rates treatment depend on your specific circumstances, so confirm the position with your accountant before you commit.

What to watch for

The main trade-off is opportunity cost. Cash spent on panels is cash you cannot deploy elsewhere, so weigh the return on the solar asset against what the same money could earn in the business. Model the payback honestly using conservative generation figures, realistic electricity prices, and a maintenance allowance, and treat any single quote with caution until you have compared it against others. The tax reliefs are valuable but they follow the rules above, so do not assume a headline "100% write-off" without checking that it is AIA rather than full expensing.

Get it costed properly

The right way to test whether buying outright is your best route is to see it costed next to the financed alternatives on the same system. We are a comparison and quote service, not a lender or financial adviser, and we connect UK businesses with vetted MCS-certified installers and funders so you can compare like for like. Start with a tailored quote, model the numbers with the finance calculator, then see how capital purchase stacks up against every other option on the finance options compared page.