Scope 3 Emissions: The Part of Your Carbon Reduction Plan Most Suppliers Get Wrong

If you've put together a Carbon Reduction Plan (CRP) to win public sector contracts, you've probably worked out your Scope 1 and Scope 2 emissions without too much trouble. Scope 1 is what comes directly out of your business - fuel in your vehicles, gas in your boiler. Scope 2 is the electricity you buy. Both are straightforward to measure because the data is sitting in your invoices.

Scope 3 is a different problem entirely. It covers everything else - and for most businesses, it's where the vast majority of their carbon footprint actually lives.

Why Scope 3 Is Different

The defining feature of Scope 3 is that the emissions happen outside your business. They're caused by things you buy, the way your staff travel to work, the waste you send off-site, and the activities of your supply chain. You don't control those processes. In many cases, you don't even have direct access to the data.

That's what makes it hard. You can't just pull a meter reading or check an energy bill. You have to gather data from suppliers, use spend-based estimates, or apply industry emission factors - and then do it again every year as things change.

Studies consistently show that Scope 3 can account for up to 80% of an organisation's total carbon footprint. For many SMEs bidding for public sector work, that means the bulk of your actual emissions impact isn't being reported accurately - or at all.

What PPN 006 Actually Requires

Procurement Policy Note 006/21 (PPN 006) is the Cabinet Office guidance that requires suppliers bidding for contracts over £5 million per year to submit a Carbon Reduction Plan. The guidance doesn't ask you to report all 15 Scope 3 categories defined by the GHG Protocol. It asks you to identify and report your most material ones.

In practice, the categories most commonly required - and most scrutinised by contracting authorities - are:

• Purchased goods and services: The emissions embedded in everything you buy to run your business, from raw materials to office supplies to outsourced services.
• Capital goods: The carbon footprint of equipment, machinery, or assets you've purchased during the reporting year.
• Business travel: Flights, train journeys, hired vehicles, and hotel stays made by your employees in the course of work.
• Employee commuting: The emissions from your staff travelling between their homes and your workplace, by whatever means they use.
• Waste generated in operations: The carbon impact of waste you send to landfill, recycling, or incineration from your day-to-day activities.

These five categories are where most SMEs have genuine, measurable emissions - and where buyers expect to see credible numbers.

The Mistakes That Get Suppliers Into Trouble

Most of the Scope 3 errors we see fall into one of three patterns. They're easy to make, and they're also easy to spot when a contracting authority knows what to look for.

• Guessing without a methodology: Putting in a round number or a low estimate without showing how you arrived at it. Buyers are increasingly trained to ask for the workings. If you can't explain your figures, the credibility of your whole CRP takes a hit.
• Leaving categories blank: Skipping commuting because it seems minor, or omitting purchased goods because the data is hard to gather. A missing category doesn't look like a gap - it looks like you didn't try.
• Treating it as a one-off: Submitting a CRP once and not updating it. PPN 006 expects annual reporting with year-on-year progress. A static document submitted two years running will raise questions.

None of these mistakes are made out of bad faith. Scope 3 is genuinely complicated, and most SMEs don't have a sustainability manager on staff. But the mistakes are avoidable - and they're costing suppliers contract opportunities.

You Don't Have to Figure This Out Alone

The good news is that Scope 3 reporting doesn't require a consultant or a dedicated team. What it requires is the right structure, the right emission factors, and a consistent methodology you can repeat each year.

CarbonVerified.uk is built specifically for UK SMEs in this position. It walks you through each Scope 3 category, uses recognised emission factors from the UK Government's conversion tables, and produces a Carbon Reduction Plan that meets PPN 006 requirements - including your Scope 3 numbers, explained clearly and auditably.

If your current CRP has gaps in the Scope 3 section, or if you're not sure whether your figures would hold up to scrutiny, it's worth taking a look before your next tender.