A customer's questionnaire asks for Scope 3. Do I need to calculate my own Scope 3 to answer it?

Usually not yet. Your customer wants your Scope 1 and Scope 2 — those become a line item in their Scope 3. Your own Scope 3 (your suppliers, your freight, your staff travel) is a separate, later exercise. Read the questionnaire's actual field labels before assuming it wants more than that.

What if I genuinely don't have last year's electricity bills?

Say so and give your best estimate from what you do have — a recent month's bill annualised, or a landlord's service-charge statement — and label it as an estimate with the method shown. A disclosed estimate with its method is more credible to a procurement reviewer than a late, silent guess, and far better than leaving the field blank.

Can I just copy a competitor's or industry-average number?

No. An industry-average intensity figure (kgCO2e per revenue or per unit) can fill a gap when you truly have nothing, but it must be labelled as an industry proxy, not presented as your measured number. Submitting someone else's actual figure as your own is not a shortcut a procurement team will accept if questioned, and it leaves you unable to answer a single follow-up question about it.

Do I need third-party assurance before I can answer a questionnaire?

Almost never at this stage. Assurance (external verification of your numbers) is what large, often listed, companies phase in over several years under frameworks like IFRS S2. A first customer questionnaire wants a number with its method shown, not an auditor's signature. Paying for assurance before you have a full year of data to assure is money spent on the wrong problem.

What is the difference between location-based and market-based Scope 2, and does my questionnaire care?

Location-based uses your grid's average factor — in Singapore, the EMA figure, identical for every buyer. Market-based reflects contracts you hold, such as renewable energy certificates. Most SME questionnaires ask for location-based only; check the field label, and only report market-based if you actually hold RECs or a green tariff with paperwork behind it.

How often will these questionnaires come, and do I need new numbers every time?

Increasingly often, and usually annually, tied to your customer's own reporting cycle. Keep one methodology note and one spreadsheet of source documents per financial year; when the next questionnaire lands — from the same customer or a new one — you update the figures rather than starting over.

Guide

How to answer a customer's carbon questionnaire: an SME survival guide

What a buyer's Scope 1/2/3 or CDP-style questionnaire actually requires, the minimum defensible answer for a small supplier, and a worked example for a 20-person logistics firm using Singapore factors.

Last updated July 2026

Why this landed on your desk

Nobody at a 20-person business asks for a Scope 3 breakdown for fun. It arrives because your customer has to report their own emissions, and your electricity bill and fuel receipts are now, mechanically, a line item in someone else's disclosure. In Singapore this is not a hypothetical: from FY2025, every SGX-listed issuer reports Scope 1 and 2 under IFRS S2, and Straits Times Index constituents add Scope 3 from FY2026. Their Scope 3 is built from suppliers' Scope 1 and 2 — which means it is built from yours. Boards of listed companies carry personal responsibility for that report under SGX listing rules 711A and 711B, which is exactly why their procurement teams have started forwarding a questionnaire to every vendor on the supplier list, regardless of vendor size. See our SGX deadlines guide for the full timetable, including where unlisted SMEs sit relative to it (nowhere, directly — the pull comes sideways, through customers).

The same pattern shows up outside Singapore too: CDP's supply-chain questionnaire, procurement portals run by multinationals, and bank ESG onboarding forms all ask a smaller supplier some version of the same three questions. None of it requires you to have run a formal reporting programme. It requires you to answer honestly, show your working, and not invent anything.

Decoding the jargon before you touch a spreadsheet

Questionnaires borrow GHG Protocol language without explaining it. Three terms cause almost all the confusion:

Scope 1, 2, 3 — whose fuel got burned. Scope 1 is fuel you burn yourself: company vehicles, gas hobs, diesel gensets, refrigerant leaks. Scope 2 is the electricity you buy — someone else's power station burned the fuel, but you consumed the result. Scope 3 is everything upstream and downstream of that: what you buy, how goods move, staff travel and commuting, and waste. For the full mapping from document to scope, see Scope 1, 2 and 3, explained in 10 minutes.
Location-based vs market-based — two ways to report Scope 2. Location-based uses the average emission factor for the grid you are physically connected to; every business on the same grid gets the same factor regardless of who they buy electricity from. Market-based reflects what you have contractually purchased — renewable energy certificates (RECs), a green tariff, or a power purchase agreement — and can only differ from location-based if you hold that paperwork. If a field just says "Scope 2 emissions" with no qualifier, assume location-based; that is what nearly every SME questionnaire actually wants.
Intensity metrics — emissions per unit of something else: per S$ of revenue, per employee, per tonne shipped, per square metre of floor area. Buyers ask for intensity so they can compare suppliers of very different sizes on the same scale. You need a total figure before you can produce an intensity figure — divide your Scope 1 + Scope 2 tonnes by whatever denominator the questionnaire specifies, and state the denominator you used.

The minimum defensible answer

Most SME questionnaires reward getting three things right over getting fifteen things approximately right.

What you genuinely need for a first answer:

Scope 1 — litres of fuel burned in vehicles or equipment you own or lease and operate, converted with a published combustion factor.
Scope 2, location-based — kWh from your electricity bill or tenant statement, converted with your grid's official factor.
The method behind both numbers — which factor, which source, which data year, and what period the figures cover. This is the single most commonly missing item, and the one procurement reviewers ask about first when a number looks unusual.

What can genuinely wait, unless the questionnaire explicitly asks for it by name:

A full 15-category Scope 3 inventory. Almost no SME questionnaire requires this on a first pass; most ask for Scope 1 and 2 with an optional or high-level Scope 3 estimate.
Refrigerant tracking, if your aircon has not needed a gas top-up — note it as "no recorded top-up this period" rather than guessing a number.
Third-party assurance or verification. That is a later-stage requirement for large, often listed, reporters — not something a first-year supplier response needs.
Market-based Scope 2, unless you actually hold RECs or a green-tariff contract. Reporting a market-based number you cannot document creates a worse problem than reporting none.

If a field asks for something outside this list and you have no data, write "not yet tracked; will include in next year's response" rather than leaving it blank or inventing a figure. Procurement reviewers see this constantly and treat an honest gap as normal; a filled-in field with no supporting method is what invites follow-up questions you cannot answer.

Evidence to keep

Keep one folder per financial year, named for the reporting period, holding:

Electricity bills or tenant/landlord statements covering the full period, with the kWh figure visible.
Fuel-card statements or pump receipts, itemised by litres and fuel type.
Aircon or refrigeration servicing invoices, even if they show no top-up — the absence of a recorded refill is itself evidence.
A one-page methodology note: which emission factors you used, their source and data year, and the reporting boundary (which sites, vehicles, and time period are included).
The completed questionnaire itself, dated, so next year's version starts from a known baseline rather than a blank form.

This is exactly the evidence trail a 3-document-a-day upload already produces if you route your bills through it instead of retyping numbers — the extraction keeps the source file, and every result carries the factor and licence behind it.

Worked example: a 20-person logistics SME

A logistics operator in Tuas runs a small office and a fleet of three delivery vans, and receives a customer's questionnaire asking for Scope 1 and Scope 2, location-based, for the last financial year.

Step 1 — Scope 2, electricity. The office's SP Group bills for the year total 42,000 kWh, all within the 2024 data year. Applying the current EMA factor:

42,000 kWh × 0.4020 kgCO₂e/kWh = 16,884 kgCO₂e ≈ 16.9 tCO₂e

Step 2 — Scope 1, fleet fuel. Fuel-card statements show the three vans used 3,600 litres of diesel across the year. Using the DEFRA 2025 diesel factor:

3,600 litres × 2.686 kgCO₂e/litre = 9,670 kgCO₂e ≈ 9.7 tCO₂e

Step 3 — total and intensity. Combined Scope 1 + 2 comes to approximately 26.6 tCO₂e for the year. If the questionnaire asks for an intensity figure per S$ million of revenue and the firm turned over S$2.4 million, that is 26.6 ÷ 2.4 ≈ 11.1 tCO₂e per S$ million revenue — stated alongside the total, with the revenue figure disclosed so the reviewer can check the arithmetic.

Step 4 — the methodology line. The completed answer states: "Scope 2 calculated as metered kWh × EMA grid emission factor (0.4020 kgCO₂e/kWh, 2024 data year, Singapore Energy Statistics 2025, location-based). Scope 1 calculated as fuel-card litres × DEFRA 2025 diesel combustion factor (2.686 kgCO₂e/litre). Reporting period: FY[year], covering the Tuas office and three company-operated delivery vans. Scope 3 not yet tracked; refrigerant servicing invoice shows no recorded top-up this period." That single paragraph answers the "show your working" question before anyone has to ask it.

If your office electricity comes through a landlord rather than a direct retail contract, the kWh figure above may need an allocation step first — see tenant or landlord: who reports the electricity? before you plug a number into Step 1.

You can reproduce steps 1 and 2 directly with the Singapore business electricity calculator and the fleet fuel calculator, or run both fields on the organization footprint calculator in one pass. For the underlying grid-factor mechanics, see the Singapore grid emission factor guide.

What not to do

Do not guess a number to avoid an empty field. An estimate with its method disclosed is defensible; a bare invented figure is not, and it is the first thing that unravels under a follow-up question.
Do not copy a competitor's or industry number and present it as measured. Use an industry-average intensity only as a clearly labelled proxy for a category you have no data on — never as a stand-in for your own metered electricity or fuel.
Do not pay for third-party assurance before you need it. Assurance verifies numbers you already have; it does not generate them, and no SME questionnaire at this stage requires it. Spend the budget on getting a full year of bills together instead.
Do not silently swap location-based for market-based. If you do not hold RECs or a green-tariff contract, report location-based only — do not quietly use a lower "green" number without the paperwork to back it.
Do not let the questionnaire's Scope 3 field push you into a rushed, undocumented estimate. If Scope 3 is optional or clearly aimed at larger suppliers, say it is not yet tracked rather than filling it with a number you cannot explain a year from now.

Why this keeps happening

This is not a one-off request. As SGX's Scope 1/2/3 timeline tightens and similar rules spread across the region, the number of customers who need your electricity and fuel data will grow every reporting cycle, not shrink. The businesses that answer calmly are the ones with a standing folder of bills, a one-page methodology note, and a habit of updating both once a year — not the ones scrambling to reconstruct twelve months of invoices the week a questionnaire arrives. Building that habit this year is the entire difference between a two-hour task and a two-week one next time.

Sources

GHG Protocol — Corporate Standard and Scope 2 Guidance: ghgprotocol.org
EMA — Singapore Energy Statistics (grid emission factor, Singapore Open Data Licence): ema.gov.sg
UK DESNZ/DEFRA — greenhouse gas conversion factors 2025 (Open Government Licence v3.0): gov.uk
SGX RegCo — sustainability reporting requirements: sgx.com/regulation
CDP — supply chain questionnaire guidance: cdp.net

Frequently asked questions

A customer's questionnaire asks for Scope 3. Do I need to calculate my own Scope 3 to answer it?: Usually not yet. Your customer wants your Scope 1 and Scope 2 — those become a line item in their Scope 3. Your own Scope 3 (your suppliers, your freight, your staff travel) is a separate, later exercise. Read the questionnaire's actual field labels before assuming it wants more than that.
What if I genuinely don't have last year's electricity bills?: Say so and give your best estimate from what you do have — a recent month's bill annualised, or a landlord's service-charge statement — and label it as an estimate with the method shown. A disclosed estimate with its method is more credible to a procurement reviewer than a late, silent guess, and far better than leaving the field blank.
Can I just copy a competitor's or industry-average number?: No. An industry-average intensity figure (kgCO2e per revenue or per unit) can fill a gap when you truly have nothing, but it must be labelled as an industry proxy, not presented as your measured number. Submitting someone else's actual figure as your own is not a shortcut a procurement team will accept if questioned, and it leaves you unable to answer a single follow-up question about it.
Do I need third-party assurance before I can answer a questionnaire?: Almost never at this stage. Assurance (external verification of your numbers) is what large, often listed, companies phase in over several years under frameworks like IFRS S2. A first customer questionnaire wants a number with its method shown, not an auditor's signature. Paying for assurance before you have a full year of data to assure is money spent on the wrong problem.
What is the difference between location-based and market-based Scope 2, and does my questionnaire care?: Location-based uses your grid's average factor — in Singapore, the EMA figure, identical for every buyer. Market-based reflects contracts you hold, such as renewable energy certificates. Most SME questionnaires ask for location-based only; check the field label, and only report market-based if you actually hold RECs or a green tariff with paperwork behind it.
How often will these questionnaires come, and do I need new numbers every time?: Increasingly often, and usually annually, tied to your customer's own reporting cycle. Keep one methodology note and one spreadsheet of source documents per financial year; when the next questionnaire lands — from the same customer or a new one — you update the figures rather than starting over.