Does Solar Count Towards Net Zero? The Honest Answer

It is one of the most common questions a sustainability lead or finance director asks, and one of the most frequently answered dishonestly: if we put solar on the roof, or sign a power purchase agreement, does it count towards our net-zero target? The honest answer is partly, and only for the right emissions — and the caveats matter more than the headline. This guide gives the straight version, because a net-zero claim built on a misunderstanding of what solar does is exactly the kind of claim that does not survive scrutiny.

The short answer: yes for market-based Scope 2, and no further

Buying renewable electricity — whether through an on-site solar array or a power purchase agreement (PPA) — reduces your market-based Scope 2 emissions. That is real, and it does count towards that part of your target. But two things immediately qualify it, and both are non-negotiable if the claim is going to hold:

1. It only touches Scope 2. It does nothing for your Scope 1 fuel use, and nothing for your Scope 3 value chain — which for most businesses is the larger part of the footprint.
2. The credibility depends on additionality. A genuine on-site installation or a well-structured PPA is far more defensible than unbundled certificates bought to flatter a number.

Get those two right and solar is a legitimate, valuable lever. Ignore them and you have a greenwashing risk dressed up as a net-zero strategy. The rest of this guide explains why.

Why “Scope 2 only” is the whole story

To see why solar counts for one thing and not others, you have to remember how emissions are categorised. Under the GHG Protocol and the UK government’s environmental reporting guidelines, a company’s greenhouse gases split into three scopes:

• Scope 1 — direct emissions from what you own: the gas in your boilers, the fuel in your fleet.
• Scope 2 — indirect emissions from the energy you buy, principally purchased electricity.
• Scope 3 — every other indirect emission across your value chain, split into fifteen categories.

Renewable electricity only changes the emissions associated with the electricity you buy — which is Scope 2, and only Scope 2. It cannot reduce the gas burned in your heating, because that is Scope 1 and has nothing to do with your electricity supply. And it cannot reduce the emissions embedded in the goods you purchase, the logistics that move them, the business travel your staff do, or the use of the products you sell — all of which are Scope 3. Our full breakdown of the three scopes is in Scope 1, 2 and 3 emissions explained, and the distinction is the single most important thing to hold onto here.

The practical consequence is stark. A company that installs solar, cuts its market-based Scope 2, and then describes itself as “well on the way to net zero” — while its Scope 1 heating runs on gas and its Scope 3 supply chain is untouched — is overstating what it has actually done, often by a very large margin. For many businesses, Scope 2 electricity is a modest slice of the total footprint, and Scope 3 is the overwhelming majority. Solar can be a genuine and worthwhile measure and still leave most of the footprint exactly where it was.

The dual Scope 2 method: two numbers, report both

Even within Scope 2, there is a nuance that decides whether a solar claim is honest. The GHG Protocol requires Scope 2 to be reported as two figures:

• The location-based figure uses the average emissions intensity of the grid. It reflects the physical electricity system, regardless of what you have contracted for — so buying solar or a PPA does not change it.
• The market-based figure reflects the specific electricity you have procured. This is the figure that on-site solar or a PPA reduces.

The honest practice is to report both, not to quietly present only the lower market-based number as if it were the whole picture. A disclosure that shows a single, flattering Scope 2 figure with no mention of which method produced it is exactly the kind of selective presentation that undermines trust and invites challenge. When we build a target, both figures are on the table, so the effect of a solar array or a PPA is shown truthfully rather than cherry-picked.

The number that keeps a claim honest: Scope 2 is reported as two figures — location-based and market-based. Solar and a PPA move only the market-based one. Reporting both is the difference between a defensible claim and a greenwashing risk.

Additionality: the difference between a real claim and a paper one

Here is where most net-zero claims quietly come apart. Two very different things can both reduce a market-based Scope 2 figure on paper, but they are not equally credible, and the difference has a name: additionality — whether your money actually caused more clean generation to exist.

• A genuine on-site solar array physically generates clean electricity you then use. It changes the real energy system. It carries real weight.
• A well-structured PPA that supports additional renewable capacity — new generation that would not otherwise have been built — likewise has additionality behind it, and stands up.
• Unbundled renewable certificates, bought purely to net down a market-based figure with no additional generation behind them, carry far less weight. A claim that leans on them is fragile the moment it is examined in a transaction, a tender, or by a regulator.

This is not a technicality; it is the whole basis on which a net-zero claim is judged credible or not. The Competition and Markets Authority’s Green Claims Code sets out that environmental claims must be truthful, substantiated and not omit material information — and a market-based figure flattered by low-additionality certificates omits a very material fact. We build targets so a PPA or an array counts where it genuinely should, and no further, which is precisely what keeps the claim safe. The way renewables are sequenced honestly into a wider plan is set out in our net-zero roadmap service.

Where solar genuinely fits: as a lever, not the product

None of this means solar is not worth doing. It means solar has to sit in the right place: as one decarbonisation lever inside a sequenced plan, not as the plan itself. A credible net-zero roadmap attacks the footprint in the order that actually cuts emissions fastest for the money:

1. Energy efficiency first — the cheapest tonne of carbon is the one you never use, and reducing demand comes before generating or buying anything.
2. Electrification of heat and transport — heat pumps replacing gas heating and an electric fleet replacing diesel are the measures that attack the Scope 1 number that renewables cannot touch.
3. On-site generation and PPAs — with demand reduced and loads electrified, solar or a PPA reduces the market-based Scope 2 for the electricity that remains.
4. Credible offsetting, last and only for the genuine residual — after the reductions are made, a small residual usually remains, and high-quality removals address that residual only, never as a way to buy down emissions that better sequencing should have cut first.

Placed in that sequence, solar does real work. Placed at the front as a substitute for the harder measures, it becomes a way of looking busy while the biggest numbers go unaddressed. Where a commercial installation is the right measure, it is delivered work in its own right — renewable-energy specialists such as EC Eco Energy handle the engineering and the install — while the honest accounting of what it counts towards stays inside the reporting. And for the genuine residual at the end, quality is everything: credible removal and offsetting partners such as Carbon Legacy address what is left after real reductions, rather than offering a shortcut around them.

The claims to avoid — and why they matter

Because this is where greenwashing risk concentrates, it is worth being explicit about the statements that do not hold:

• “We run on 100% renewable electricity, so we’re net zero.” Renewable electricity addresses market-based Scope 2. It says nothing about Scope 1 or Scope 3, so it is nowhere near a whole-company net-zero claim.
• “Our solar array makes us carbon neutral.” One measure, one part of one scope. A carbon-neutral claim covers the whole footprint and needs a recognised standard, such as PAS 2060 or ISO 14068, behind it.
• “We’ve offset our emissions.” Offsetting is legitimate only for the genuine residual after real reductions, and only at a quality that survives scrutiny — not as a first move to avoid decarbonising.

These are not pedantic distinctions. An unquantified or overstated environmental claim is a live legal and reputational exposure under the CMA’s Green Claims Code, and it can be challenged in due diligence, undermine a tender, or attract regulatory scrutiny. Honest, quantified disclosure — report both Scope 2 figures, be clear about additionality, be explicit about what a PPA does and does not cover — is both better compliance and a stronger competitive position. Our ESG for tenders and PQQs page sets out how buyers now probe exactly these claims.

What this means for your target

If you are weighing up solar or a PPA as part of a net-zero commitment, the useful way to think about it is this: it will improve your market-based Scope 2 figure, honestly and defensibly, provided it has genuine additionality and you report both Scope 2 numbers. It will not, on its own, move your Scope 1 or your Scope 3 — which for most companies is where the bulk of the work, and the bulk of the footprint, actually sits. A plan that treats solar as one sequenced lever among several is credible. A plan that treats it as the answer is not.

Getting that right is exactly what keeps a target both achievable and safe from challenge. Before you commit, it is worth establishing your full footprint across all three scopes — so you know what solar will and will not do for it. Our carbon footprint and baseline service builds that starting line, our Scope 3 and supply-chain hub tackles the part solar never reaches, and if you are still working out which duties apply, who has to report under SECR sets out the thresholds.

Get an honest read on what counts

We answer this question the same way every time: yes, solar counts — for market-based Scope 2, with genuine additionality, and no further. That honesty is the point. A net-zero claim we help you make is one you can defend in a boardroom, a tender or a due-diligence process, because it says exactly what each measure genuinely achieves.

If you would like a straight read on your own footprint and where renewables do and do not move your numbers, book an ESG readiness call and we will reply within one working day. To go deeper first, start with our net-zero roadmap service, our full SECR and ESG compliance support, or see how a plan is anchored to genuinely local net-zero policy and grid context in ESG compliance in Manchester.

This article references partner companies in the SEO Dons network. Methodology and government sources, verified 2 July 2026: the GHG Protocol Corporate Standard, the UK government’s environmental reporting guidelines, and the Climate Change Act 2008 (the statutory basis for the UK’s net-zero-by-2050 target).