Carbon Reporting for US Small Businesses: A Practical Getting-Started Guide
Why US Small Businesses Are Getting Carbon Questionnaires
Carbon reporting for US small businesses is no longer optional. American SMEs are receiving supply chain carbon data requests because of two major drivers in 2026:
1. SEC Climate Disclosure Rule — The US Securities and Exchange Commission's climate disclosure rules require large listed companies to report Scope 1 and 2 emissions, with Scope 3 required where material. This directly triggers supply chain data collection from SME suppliers.
2. California SB 253 and SB 261 — California's Climate Corporate Data Accountability Act requires companies with revenues above $1 billion doing business in California to report all three scopes from 2026, and companies above $500M to report climate-related financial risks. These rules create a cascade of supplier data requests across all 50 states.
If you supply goods or services to any Fortune 500 company, major retailer, or publicly listed US business, expect a carbon data request this year.
US Emission Factors: EPA eGRID and GHGRP
For US carbon reporting, the standard emission factors come from the EPA eGRID database for electricity and the EPA's Emission Factors for Greenhouse Gas Inventories for fuel combustion.
| Source | EPA Factor | Unit |
|---|---|---|
| US average grid electricity | 0.386 | kgCO2e per kWh |
| Natural gas (commercial) | 53.06 | kgCO2e per MMBtu |
| Diesel (distillate fuel) | 73.96 | kgCO2e per MMBtu |
| Gasoline | 70.22 | kgCO2e per MMBtu |
| Propane | 63.07 | kgCO2e per MMBtu |
Note: US electricity factors vary substantially by region. California (CAMX): 0.198 kgCO2e/kWh. Midwest (MROW): 0.549 kgCO2e/kWh. Northeast (NEWE): 0.258 kgCO2e/kWh. Always use your regional eGRID subregion factor for Scope 2.
Worked Example: US Small Business Carbon Calculation
Sample company: A 30-person Chicago-based professional services firm
Scope 1 — Natural gas: 2,400 therms × 5.302 kgCO2e/therm = 12,725 kgCO2e = 12.7 tCO2e
Scope 2 — Midwest electricity (MROW): 85,000 kWh × 0.549 = 46,665 kgCO2e = 46.7 tCO2e
Scope 3 — Business travel (air): 45,000 revenue miles economy = 13.1 tCO2e
Scope 3 — Commuting: 30 employees × 15 miles avg × 250 days × 0.404 kg/mile = 45.5 tCO2e
Total: 118.0 tCO2e | Per employee: 3.9 tCO2e/FTE
What Methodology Do US Buyers Expect?
The GHG Protocol Corporate Standard is the universal answer — it is what Walmart, Amazon, Apple, Google, and every major US enterprise specifies on their supplier questionnaires. The GHG Protocol is methodology-agnostic on emission factors, so using EPA eGRID factors within the GHG Protocol framework is fully compliant.
What US Carbon Questionnaires Actually Ask
US enterprise sustainability questionnaires — whether through EcoVadis, Salesforce Net Zero Cloud, or direct CDP surveys — typically request:
- Scope 1 and 2 totals in metric tonnes CO2e (not short tons)
- Scope 3 breakdown by category where available
- Emissions intensity per employee or per $1M revenue
- Methodology used (GHG Protocol is the correct answer)
- Year of data and whether it has been externally assured
Important: US buyers want metric tonnes (tCO2e), not US short tons. One metric tonne = 1,000 kg. Do not confuse units.
Getting Started: The 3-Step Process for US SMEs
- Collect 12 months of utility bills — electric bills (kWh usage), gas bills (therms or CCF), and fuel purchase records
- Calculate using EPA factors — apply your regional eGRID factor to electricity, and EPA combustion factors to gas and fuel
- Generate a Carbon Passport — DeCarbonOPS produces a shareable verification URL accepted by US, EU, and global procurement portals. Free for your first annual report.
Frequently Asked Questions
Do US small businesses have to report carbon emissions?
Most US SMEs are not directly required to report carbon emissions under federal law. However, the SEC climate disclosure rules require large listed companies to report Scope 1 and 2 (and Scope 3 where material), creating supply chain carbon requests. California SB 253 requires companies with $1B+ revenue doing business in California to report all three scopes from 2026. These rules create a cascade of supplier data requests reaching SMEs across all 50 states.
What emission factors do US businesses use for carbon reporting?
US businesses use EPA eGRID factors for electricity (which vary by regional grid) and EPA Emission Factors for Greenhouse Gas Inventories for fuel combustion. US average electricity: 0.386 kgCO2e per kWh. Regional factors vary significantly: California (CAMX) 0.198, Midwest (MROW) 0.549, Northeast (NEWE) 0.258. For natural gas: 53.06 kgCO2e per MMBtu. Diesel: 73.96 kgCO2e per MMBtu.
What methodology do US enterprise buyers expect on supplier questionnaires?
The GHG Protocol Corporate Standard is the universal answer on US supplier carbon questionnaires. It is specified by Walmart, Amazon, Apple, Google, and every major US enterprise. The GHG Protocol is methodology-agnostic on emission factors, so using EPA eGRID factors within the GHG Protocol framework is fully compliant.
US buyers ask for tonnes — should I report in metric tonnes or short tons?
Always report in metric tonnes CO2e (tCO2e), not US short tons. One metric tonne equals 1,000 kg. One short ton equals 907 kg. Enterprise sustainability systems including CDP, EcoVadis, and Salesforce Net Zero Cloud all use metric tonnes. Reporting in short tons without specifying will make your data incomparable and may trigger a rejection.
How do I respond to a Walmart or Amazon supplier sustainability questionnaire on carbon?
Walmart's Project Gigaton and Amazon's Climate Pledge both ask suppliers for Scope 1, 2, and 3 emissions in tCO2e using GHG Protocol methodology. The fastest way to respond is to generate a DeCarbonOPS Carbon Passport (15–25 minutes), which provides your Scope 1, 2, and 3 totals, emissions intensity, and a verification URL — all the data these platforms require.
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