BBP Green Lease Toolkit: The Solar Clauses an Owner Needs

If you own a let building and want solar on the roof, the lease decides whether you can. The Better Buildings Partnership (BBP) Green Lease Toolkit is the document most commercial solicitors reach for when that question comes up, so it is worth knowing what it actually gives you before the first draft goes to the tenant’s side.

This article is the short version for an owner: the three clause tiers, the one hierarchy that supports solar, and five clauses to ask for. The full mechanics of cost-sharing, consent and the service charge are in our green lease and solar guide; this piece is the drafting checklist that sits on top of it.

What the toolkit is, and what it is not

The BBP toolkit is a set of model clauses and guidance for commercial leases. It is not law and it does not bind anyone who has not written it into their lease. Its value is that it gives landlord and tenant a neutral, widely recognised starting point, so the negotiation is about degree rather than principle. A tenant’s solicitor who recognises the language is less likely to treat a solar clause as a landlord land-grab.

It also helps to be clear about what a green lease is not. It is not a separate type of tenure. It is an ordinary full-repairing lease with environmental obligations added, usually covering energy and water data, alterations that could harm the EPC, cooperation on efficiency works and provision for on-site renewables.

Pick the clause tier before you pick the clause

The toolkit grades its clauses by how binding they are. The tier you ask for matters more than the wording of any single clause, because it sets how far the tenant can resist.

Most negotiated outcomes sit in the medium band. If solar is a priority, the useful move is to set medium green as the default for new lettings so that the right to install is not reopened tenant by tenant.

The hierarchy that supports solar

The renewable-energy clause in the toolkit sets a preference order for how a building meets its electricity. On-site generation comes first, a power purchase agreement second, and a green tariff last. For an owner this is leverage: it presents on-site solar as the toolkit-endorsed route rather than a landlord preference. It also tells you which instrument to use if you cannot fund the array yourself, which is a landlord-to-tenant PPA.

Five solar clauses to draft in

These are the clauses we would look for in a lease or a one-page addendum. None is exotic; the point is that each closes a gap a standard lease leaves open.

1. Right to install. The landlord reserves the right to install, own and operate solar PV on the roof and common parts, and the tenant agrees not to obstruct it. Without this, a tenant who holds the roof as part of its demise can say no.
2. Cost mechanism. State how the capital is recovered: a PPA unit price, a capped annual green-lease contribution, or rent. Say expressly that the capital cost is not charged to the service charge. Under the RICS Service Charges in Commercial Property standard (2nd edition, in force 31 December 2025) the initial capital cost of new plant is not recoverable that way, so a clause that tries to is an invitation to a dispute. We cover this in can a landlord recover solar costs through the service charge.
3. The tenant-savings cap. The tenant’s contribution should never exceed what the solar saves them, measured against a stated grid reference price. This single line is what makes the deal fair and what makes a tenant willing to sign.
4. Data sharing. Half-hourly consumption data is needed to size the array honestly and to measure self-consumption afterwards. It also feeds the owner’s own ESG reporting.
5. EPC cooperation. A commitment not to carry out alterations that worsen the EPC. Letting below EPC E has been unlawful in England and Wales since 1 April 2023, and the Government’s interim response of 18 June 2026 proposes EPC B by 2031 for privately rented non-domestic buildings over 1,000 square metres, subject to secondary legislation. A lease that protects the rating protects lettability.

When you cannot reopen the lease

Most owners are not drafting from scratch; they have a rent roll of leases already signed. The practical instrument is a short addendum or side letter covering the five points above. The tenant-savings cap is your negotiating lever, because cheaper power is a reason for the tenant to cooperate rather than a concession. If the building is multi-let, each lease may sit at a different point on the tier scale, and you will also need sub-metering to apportion the saving; the metering side is covered in multi-let building solar metering.

Frequently asked questions

Is the BBP Green Lease Toolkit mandatory?

No. It is a recognised model, not a legal requirement. It only binds the parties if they write its clauses, or their own versions, into the lease or an addendum.

Which clause tier should I ask for if I want solar?

Medium green is the common institutional position and a realistic default for new lettings. Dark green is reasonable for long leases or tenants with their own ESG targets. Light green is usually too weak to secure a right to install.

Can the toolkit make a tenant pay for my solar?

Not by itself. It supports a contribution, but only up to the tenant’s own savings from the solar. The amount and mechanism are agreed in the lease or an addendum.

Where do I start if I want to model this for a specific building?

Start with the lease terms and the tenant mix, because they decide which mechanism works. If you want to talk it through for a particular building, send an enquiry and we reply by email.