Scope 3 Emissions: What UK Businesses Need to Know

For many UK businesses, Scope 3 emissions represent the part of their carbon footprint they understand the least and control the most poorly. They sit outside the factory fence, across a supply chain that stretches in both directions; both upstream through raw material suppliers and downstream through the customers buying your products.

That complexity is a real challenge. But Scope 3 is also where the majority of most organisations’ emissions live, which makes it increasingly difficult to set aside.

This guide explains what Scope 3 emissions are, why they matter specifically to energy-intensive UK businesses, what the regulatory landscape currently requires, and how decisions made about energy (particularly around Scope 2) have a more direct bearing on Scope 3 than many businesses realise.

For a broader overview of how Scope 1, 2 and 3 fit together, see our guide to reducing Scope 1-3 emissions.

What Are Scope 3 Emissions?

The Greenhouse Gas (GHG) Protocol groups a business’s carbon emissions into three categories. Scope 1 covers emissions from sources the business directly owns or controls: fuel in company vehicles, gas in on-site boilers. Scope 2 covers emissions from purchased energy, primarily electricity. Scope 3 covers everything else.

In practical terms, Scope 3 includes emissions that occur because of a business’s activities but outside its direct operational boundary. The GHG Protocol identifies 15 categories of Scope 3 emissions, covering both upstream activities (what goes into what you make or buy) and downstream activities (what happens to your products after they leave your site).

The defining characteristic of Scope 3 is that a business cannot reduce these emissions simply by changing its own operations. It requires engaging with suppliers, customers, logistics partners, and the broader value chain.

Power Zero’s Solar PPA solutions offer a valuable starting point for reducing the carbon intensity of your operations, and by extension, the carbon profile of what you supply to others.

Why Scope 3 is Often the Largest Part of an Industrial Carbon Footprint

For most businesses in manufacturing, automotive, pharmaceuticals, chemicals, and food and beverage, Scope 3 is not a marginal concern. According to McKinsey, Scope 3 emissions typically represent around 90% of a company’s total emissions. CDP’s analysis of corporate disclosures found that supply chain emissions are, on average, 26 times greater than a company’s combined Scope 1 and 2 emissions.

The reason is structural. Manufacturing is a transformative process: raw materials come in, energy is applied, products go out. Every stage of that process involves third parties whose own carbon footprints are, technically, part of your Scope 3 exposure.

An automotive plant sources steel, aluminium, glass, plastics, and electronics, all of which require significant energy to produce. Based on McKinsey’s analysis of automotive upstream emissions, steel and aluminium together typically account for 45% to 65% of upstream Scope 3 emissions for internal combustion engine vehicles. A pharmaceutical manufacturer procures chemical precursors and packaging materials across global supply chains. A food producer is connected to agricultural supply chains where land use, fertiliser production, and transport generate substantial emissions before anything reaches the factory gate.

On the downstream side, many industrial products continue to consume energy throughout their useful lives. Vehicles emit during use. Chemical formulations are processed further. Equipment runs for years or decades.

This upstream-downstream exposure is why Scope 3 tends to dwarf Scope 1 and 2 combined, and why the instinct to defer it until Scope 1 and 2 are fully resolved can end up delaying progress indefinitely.

Which Scope 3 Categories Matter Most for Industrial Businesses

The GHG Protocol’s full list of 15 Scope 3 categories covers scenarios relevant to every type of organisation, from retail businesses to financial institutions. For energy-intensive UK manufacturers and industrial operations, attention is most usefully concentrated on four.

Category 1: Purchased goods and services

For most manufacturers, this is the single largest Scope 3 source. CDP data shows that Categories 1 and 11 combined represent 84% of reported Scope 3 emissions across industries. The carbon embedded in raw materials, components, and bought-in goods accumulates quickly at high-volume production. For pharmaceuticals and chemicals, the carbon intensity of chemical feedstocks is similarly material, with Category 1 comprising 58% of total Scope 3 emissions for the chemicals sector in CDP’s 2021 dataset.

Category 4: Upstream transportation and distribution

The movement of materials and components to your site carries a carbon cost that reflects the distances involved, the modes of transport used, and the efficiency of the logistics networks your suppliers operate. In global supply chains, this is rarely negligible.

Category 11: Use of sold products

Where your products consume energy during their operational life, those lifetime emissions are classified as your Scope 3. For automotive manufacturers, this category is particularly significant: according to S&P Global Mobility, use-phase emissions currently make up approximately 70-80% of an automaker’s carbon profile. A vehicle’s lifetime fuel consumption typically generates five to ten times the emissions of manufacturing it.

Category 12: End-of-life treatment of sold products

What happens to your products when they are no longer useful, whether they are recycled, incinerated, or landfilled, generates emissions that also sit within your Scope 3 boundary.

Understanding which categories are material for your specific sector is the necessary starting point for any credible Scope 3 strategy. Attempting to address all 15 simultaneously is neither practical nor necessary.

What UK Businesses Are Currently Required to Report

The question of legal obligation is one of the most searched and least clearly answered parts of the Scope 3 conversation. The honest picture is more nuanced than most guides acknowledge.

Streamlined Energy and Carbon Reporting (SECR)

Streamlined Energy and Carbon Reporting (SECR) applies to large UK companies meeting two of three criteria: more than 250 employees, turnover above £36 million, or balance sheet above £18 million. Under SECR, qualifying businesses must report their Scope 1 and Scope 2 emissions in their annual Directors’ Report. 

Scope 3 reporting is encouraged but remains voluntary under this framework. 

It is also worth noting that as of April 2025, the Companies Act size thresholds were updated, meaning SECR no longer aligns exactly with the Companies Act definition of “large” — some businesses reclassified as medium under the new Act thresholds may still fall within SECR scope.

Task Force on Climate-related Financial Disclosures (TCFD)

Task Force on Climate-related Financial Disclosures (TCFD) requirements have applied to large UK listed companies and financial institutions since 2022. TCFD-aligned reporting typically involves some consideration of value chain emissions and climate-related risk, though the specific Scope 3 disclosure expectations vary by framework and sector.

The Corporate Sustainability Reporting Directive (CSRD)

The Corporate Sustainability Reporting Directive (CSRD) is the regulation most likely to extend mandatory Scope 3 reporting to a wider group of UK businesses in the near term, not directly, but through supply chain pressure. The CSRD requires in-scope EU companies to report their gross Scope 3 emissions across all material categories under ESRS E1. For UK manufacturers supplying large EU customers, this creates an indirect obligation: if your customer must disclose their Scope 3, they will need emissions data from you. 

That data request is already arriving in procurement processes across multiple sectors. Note that the EU Omnibus Simplification Package, provisionally agreed in late 2025, has revised CSRD thresholds upward, but the Scope 3 reporting requirement itself remains in place.

Carbon Border Adjustment Mechanism (CBAM)

Carbon Border Adjustment Mechanism (CBAM) is relevant for certain industries. CBAM is a carbon pricing mechanism applied by the EU to imports of specific carbon-intensive goods, currently including steel, aluminium, cement, fertilisers, and electricity. UK manufacturers exporting these products to the EU will need to account for the embedded carbon in their products, which is directly connected to the carbon intensity of their production processes and energy sources.

The practical picture is this: mandatory Scope 3 reporting for most UK businesses remains limited in formal scope. But the supply chain, procurement, and regulatory pressure driving de facto disclosure requirements is growing faster than the formal legislative timeline suggests.

The Link Between Scope 2 and Scope 3 Progress

One of the most underappreciated dynamics in corporate carbon strategy is the connection between how a business sources its energy (Scope 2) and how that flows through into its customers’ Scope 3 exposure.

When your business generates or purchases lower-carbon electricity, it reduces the carbon intensity of everything you produce on that energy. The goods you manufacture become less carbon-intensive in their production. For the companies buying those goods, the embedded carbon in their purchased inputs (their Category 1 Scope 3) falls as a result.

This matters practically for two reasons.

1. First, it means that improving your Scope 2 performance through on-site renewable generation is not only a direct emissions reduction for your business. It also strengthens the carbon story you can present to your own customers, who may be under increasing pressure to account for and reduce their Scope 3. In sectors with sophisticated sustainability procurement processes, this is becoming a genuine commercial differentiator.
2. Second, it means the traditional sequencing argument (“we’ll fix Scope 1 and 2 before we worry about Scope 3”) does not mean Scope 3 progress has to wait. Addressing Scope 2 through cleaner on-site energy generation begins improving your Scope 3 profile for downstream customers at the same time.

The carbon intensity of your production process is determined significantly by the carbon intensity of your energy supply. Changing that supply changes both numbers.

Practical Steps for Reducing Scope 3 Emissions

Scope 3 reduction is a longer game than Scope 1 or 2. The emissions are more difficult to measure, the levers are more distributed, and progress depends partly on decisions made by organisations you don’t control. Acknowledging that openly is not defeatism. It is the starting point for a realistic strategy.

Here are some steps on reducing scope 3 emissions:

• Establish a baseline for your material categories. Before targeting reductions, you need to understand where your Scope 3 emissions actually come from. Focus first on the categories most relevant to your sector (for most industrial businesses, Categories 1, 4, 11, and 12 are the starting point). Use available spend data, logistics records, and supplier information to build an initial estimate. It will be imperfect. That is normal and expected at this stage.
• Get Scope 1 and 2 under control first. Reducing your direct emissions and your purchased energy emissions gives you a stronger baseline, reduces your own contribution to other organisations’ Scope 3, and builds internal credibility for the wider sustainability programme. It is also where the most direct operational control exists.
• Engage key suppliers on emissions data. Supplier engagement is the most commonly cited Scope 3 lever and the most commonly avoided one, because it is genuinely difficult. According to CDP, fewer than half of companies that request environmental data from their suppliers actually receive it. For businesses with large, complex supply chains, starting with the ten or twenty suppliers that account for the majority of Category 1 spend is more productive than attempting a full supply chain programme immediately.
• Incorporate carbon intensity into procurement decisions progressively. Not every procurement decision can or should be made on carbon grounds. But introducing carbon data as a consideration in supplier selection and long-term contract discussions begins to shift the commercial incentives in the right direction. Only 15% of companies disclosing to CDP have set a Scope 3 target, which means early movers have a real opportunity to differentiate on this point in supply chain relationships.
• Build towards verified reporting. As disclosure expectations increase, the difference between estimated and verified Scope 3 data will become more significant. Putting the right data collection infrastructure in place now, tracking energy consumption, logistics records, supplier emissions, and product lifecycle data, reduces the difficulty of meeting future reporting requirements.

How Energy Decisions Affect Your Scope 3 Reporting

The connection between energy procurement and Scope 3 is often treated as indirect or long-term. In practice, it is more immediate than that.

For businesses in energy-intensive sectors, the carbon intensity of production is strongly correlated with the carbon intensity of the energy used in that production. A manufacturing facility running on grid electricity at the current UK carbon intensity is producing goods with a higher embedded carbon per unit than a comparable facility generating a significant portion of its energy from on-site solar.

That difference shows up in supplier emissions disclosures, in product lifecycle assessments, in CBAM calculations for EU-bound goods, and in the Scope 3 Category 1 data of customers asking what carbon is embedded in what they’re buying from you.

A Solar PPA provides access to on-site renewable electricity at a fixed rate below grid cost, without capital expenditure, while simultaneously reducing the carbon intensity of production processes. The emissions reductions are auditable, the generation data is metered, and the impact feeds through into both your own Scope 2 reporting and the Scope 3 reporting of the businesses in your supply chain.

For businesses beginning to assess their Scope 3 exposure and looking at practical, near-term levers, on-site energy generation is one of the most direct and financially defensible starting points available.

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FAQs

Is Scope 3 reporting mandatory in the UK?

Not broadly, at present. SECR requires large UK companies to report Scope 1 and Scope 2 emissions; Scope 3 reporting is encouraged but not currently mandated under that framework. However, businesses supplying large EU companies subject to CSRD requirements will increasingly need to provide Scope 3 emissions data through supply chain disclosure requests. The practical obligation is already arriving in many sectors ahead of formal regulation.

What is the difference between Scope 2 and Scope 3 for energy?

Scope 2 covers the emissions from electricity and energy your business purchases and uses directly. Scope 3 covers emissions from energy and activities outside your direct operations, including the emissions generated in producing the goods and materials you buy, and the energy consumed by your products once they leave your site. Improving your Scope 2 performance by switching to lower-carbon energy directly reduces the carbon intensity of your production, which flows through into your customers’ Scope 3 Category 1 data.

Can on-site solar reduce Scope 3 emissions?

Yes, indirectly but meaningfully. On-site solar reduces your Scope 2 emissions by displacing grid electricity with renewable generation. That lower-carbon production process reduces the embedded carbon in the goods you manufacture. For businesses selling into supply chains where customers must report their own Scope 3 (Category 1: purchased goods and services), lower embedded carbon in your products makes your customers’ Scope 3 reporting more favourable. It is one of the most directly available levers for improving your contribution to downstream Scope 3 exposure.

What is Category 1 Scope 3?

Category 1 (purchased goods and services) covers the emissions generated in producing the raw materials, components, and services that your business buys. For manufacturers and industrial businesses, it is typically the largest single Scope 3 category. It is driven by what you buy, how carbon-intensive those inputs are to produce, and the energy mix of the suppliers making them.