Comparison · Solar lease vs PPA

Solar lease vs PPA — UK commercial 2026

Solar lease and PPA are both structures where you don't own the system. But they differ fundamentally on how you pay (fixed monthly versus pay-per-kWh), who bears generation risk (you versus the developer), and how the contract behaves over time. The choice depends on your demand profile, electricity price view, and operational preferences.

Headline answer

Solar lease (operating) gives fixed predictability — you pay the same monthly rent regardless of generation. PPA gives variability tied to actual production — you pay per kWh consumed. PPA shifts generation risk to the developer; lease keeps it with you. For sites with stable demand, both work; for sites with variable demand, PPA's pay-per-kWh structure aligns better.

Side-by-side

Criterion	Solar lease (operating)	Power Purchase Agreement (PPA)
Payment structure	Fixed monthly rent regardless of generation	Per-kWh tariff on consumed solar
Generation risk	Lessee bears (lessor doesn't guarantee output)	Developer bears (you only pay for what's generated)
Contract length	5-8 years typical	20-25 years typical
Balance sheet treatment	Off-balance-sheet (FRS 102 small-entity)	Off-balance-sheet always
Ownership at end	Lessor; option to extend/acquire	Developer; system can transfer at end of term
Maintenance	Often included in rent	Always included (developer responsibility)
Lifetime cost (£200k system)	£40-70k more than capital purchase	£400-700k more than capital purchase
Best for	Stable demand, 5-8yr contractual horizon	Variable demand, 20+yr property tenure, zero capex priority

Which one for which situation

How variable is your electricity demand year to year?
Stable demand (manufacturing, continuous operations, 24/7 sites): lease is fine because you'll consume similar volumes each year. Variable demand (seasonal, holiday-affected, growth-trajectory uncertain): PPA aligns better because you only pay per kWh consumed.
How long is your expected occupation of the building?
Lease (5-8 years): manageable risk if you're uncertain about long-term occupation. PPA (20-25 years): much higher risk if your occupation horizon is uncertain. Match contract length to occupation certainty.
Do you want operational simplicity or fixed-cost predictability?
Operational simplicity (no metering complexity, no per-kWh accounting): lease — same payment every month, simple opex line. Fixed-cost predictability with consumption alignment: PPA — pay-per-kWh tied to actual consumption, lower bills in low-consumption months.
Are you in a building that may be sublet or change tenants?
Lease typically transfers more cleanly to new occupants because the obligation is "rent for asset access". PPAs are more complex on tenant changes because the offtake commitment needs to transfer or terminate. Multi-tenant or short-let buildings usually fit lease better than PPA.

Solar lease (operating) vs Power Purchase Agreement (PPA) FAQs

Is solar lease cheaper than PPA?

On most commercial sites, yes — solar lease typically costs £40-70k more than capital purchase over 25 years; PPA typically costs £400-700k more. The difference is in contract length and developer return. Lease is shorter (5-8 years) so the lessor margin compounds less. PPA is longer (20-25 years) so developer margin compounds materially.

Can I have a solar lease and a PPA on the same building?

Theoretically yes (e.g. lease the rooftop solar capacity, PPA the ground-mount adjacent). In practice unusual because installer/developer ecosystem is structured around one-or-the-other. Most projects pick one. Hybrid structures (lease for rooftop, PPA for adjacent solar farm) exist but require specialist developer engagement.

What happens at the end of the lease versus the end of the PPA?

Lease end: typically option to acquire system at fair market value, extend lease at reduced rate, or have lessor remove the system (rare). PPA end: typically system ownership transfers to building owner at no cost (or nominal value), or is removed if not commercially viable to maintain. Both structures need explicit end-of-term provisions in the contract.

Do solar leases and PPAs both qualify for SEG export tariffs?

For solar lease: lessee typically captures SEG export revenue (paying the lessor a fixed rent regardless of export). For PPA: developer typically captures SEG export revenue (factored into their return; offtaker only pays for self-consumed kWh). Confirm in the specific contract — both arrangements occur.

Which is more popular in the UK commercial market?

PPA dominates large-scale (£500k+) commercial solar projects because PPA developer ecosystem is larger and ticket sizes are higher. Solar lease dominates mid-market (£100k-£500k) where lessors compete on speed and structural flexibility. Capital purchase dominates the small-scale (<£100k) where capex is more easily absorbed.

Operating lease (full page)

Off-balance-sheet finance lease with fixed monthly rent. Mechanics, worked example.

PPA (full page)

Pay-per-kWh structure with developer ownership and operational responsibility.

Finance lease vs operating lease

The other lease comparison most often confused with this one.

Both offer zero upfront cost — here is where they diverge

Solar lease and power purchase agreements share a critical characteristic: you do not own the panels. A third-party developer or finance company installs the system at their expense, and you pay an ongoing charge to use the electricity. The difference is in how that charge is calculated — and the implications for budgeting, risk, and flexibility are significant.

For UK commercial premises, both are less common than ownership routes (green loans, asset finance) because ownership unlocks AIA and SEG income. But for certain businesses — particularly those with cash constraints, leased premises, or off-balance-sheet requirements — they deserve serious consideration.

How a solar operating lease works

Under an operating lease, you pay a fixed monthly rental to use the solar installation. The payment is set at contract inception and may increase annually by an agreed RPI/CPI index. The developer owns and maintains the system; you simply consume the electricity it generates and pay for grid top-up as normal.

Operating lease characteristics

Fixed monthly payment regardless of how much the panels generate, developer handles all O&M, IFRS 16 requires most leases to be on-balance-sheet (right-of-use asset + liability), no ownership at end of term.

Budgeting advantage

The fixed payment makes budgeting simple — you know exactly what you will pay each month regardless of solar generation levels, seasonal variation, or equipment performance. Useful for businesses with tight financial controls.

How a PPA works

Under a PPA, your payment is calculated per kWh of electricity generated. If the system produces 250,000 kWh in a year and your contract rate is £0.09/kWh, you pay £22,500 that year. In a poor solar year, you pay less; in a sunny year, you pay more — but always at a rate below grid tariff, so you always save.

PPA characteristics

Variable payment tied to actual generation, developer owns and maintains system, typically off-balance-sheet (no right-of-use asset), rate usually 10–20% below grid tariff, index-linked escalation.

Generation risk

The PPA developer absorbs system performance risk. If panels underperform due to equipment failure or shading, you do not pay for electricity that was not generated. This is meaningfully different from a lease where you pay the fixed rent regardless.

Key comparison: lease vs PPA

Factor	Operating Lease	PPA
Payment structure	Fixed monthly rental	Per kWh generated
Payment predictability	Highly predictable	Varies with solar generation
Who bears performance risk	You (fixed regardless of output)	Developer (you pay only for kWh)
Ownership	Developer	Developer
IFRS 16 balance sheet	Usually on-balance-sheet (ROU asset)	Usually off-balance-sheet
O&M responsibility	Developer	Developer
Minimum generation guarantee	None (you pay regardless)	Implicit (you pay per kWh)
Typical term	10–20 years	15–25 years
Early exit cost	Significant (fixed obligation)	Significant (long-term contract)
SEG export income	Developer keeps	Developer keeps

Financial modelling: which saves more?

The answer depends on your solar irradiation, system size, and negotiated rates. Here is a simplified comparison for a 100kWp system (estimated 90,000 kWh/year generation) at a site with current grid rate of £0.28/kWh:

Scenario	Operating Lease	PPA
Annual generation value	90,000 kWh at £0.28 = £25,200	90,000 kWh at £0.28 = £25,200
Annual payment	£1,200/month x 12 = £14,400	90,000 kWh x £0.09/kWh = £8,100
Annual net saving	£25,200 less £14,400 = £10,800	£25,200 less £8,100 = £17,100
Low-sun year (70,000 kWh)	£25,200 less £14,400 = £10,800 (same)	70,000 x £0.28 less 70,000 x £0.09 = £13,300
High-sun year (110,000 kWh)	£25,200 less £14,400 = £10,800 (same)	110,000 x £0.28 less 110,000 x £0.09 = £20,900

In most scenarios, the PPA delivers higher savings because you pay only for actual generation at a steep discount to grid rate. The lease savings are capped regardless of performance. The only scenario where a lease wins is if your grid rate falls sharply while your lease rate is already locked in.

The accounting treatment difference

Under IFRS 16, operating leases over 12 months must typically be recognised on the balance sheet as a right-of-use asset and corresponding lease liability. This removes the traditional off-balance-sheet appeal of leasing for many businesses.

PPAs are generally structured to avoid IFRS 16 treatment because the payment is variable (per kWh) rather than fixed. This makes PPAs genuinely off-balance-sheet for most businesses — a meaningful advantage if your company has borrowing covenants or debt ratio targets.

Which should you choose?

Choose an operating lease if

Absolute payment predictability is your priority, you have budgeting constraints that make variable payments difficult to manage, or your grid consumption is highly seasonal and you prefer fixed costs.

Choose a PPA if

You want to maximise savings (PPAs typically save more), you want genuine off-balance-sheet treatment, or you prefer to pay only for electricity actually generated.

Consider ownership instead

Both lease and PPA involve the developer keeping SEG export income and you forgoing AIA tax relief. For most profitable UK businesses with stable cash flow, a green loan or asset finance arrangement delivers superior long-term economics.

Need this comparison run on your specific numbers?

We model both structures side-by-side using your postcode, half-hourly demand profile, accounting position, and balance sheet preferences. Five working days from enquiry to indicative comparison.

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