From utility bills to a Scope 1 and 2 emissions inventory

Corporate climate disclosure has moved from voluntary to scheduled. The good news for the teams who have to produce the numbers is that most of a building or company's Scope 1 and 2 emissions come directly from data that is already on the utility bills arriving every month. The work is not inventing data. It is extracting it cleanly and applying the right factors.

What the scopes actually mean

Scope 1 for most buildings means the natural gas bill, which reads differently from an electricity bill: consumption arrives in cubic metres or gigajoules, and the delivery, transportation and commodity lines each behave differently. How a natural gas bill is structured covers what to take from it and what to ignore.

The GHG Protocol splits emissions into three scopes. Scope 1 is direct combustion you control, for example natural gas burned on site. Scope 2 is the emissions from the electricity, steam, heating or cooling you purchase. Scope 3 is everything else in your value chain. For most buildings and many companies, Scope 1 and 2 are the parts you can build almost entirely from metered energy: gas volumes and electricity consumption, multiplied by the appropriate emission factors.

Why 2026 raised the stakes

California's climate disclosure laws set the pace for large companies. Under SB 253, US entities with revenue over $1 billion that do business in California must report Scope 1 and 2 emissions starting in the 2026 cycle, with Scope 3 following in 2027, using the GHG Protocol. SB 261 adds climate-risk reporting for companies over $500 million in revenue. Deadlines and enforcement have shifted during rulemaking, so confirm the current dates, but the direction is set.

Canadian organizations face the same direction of travel. The Canadian Sustainability Disclosure Standards align with the global ISSB baseline, and OSFI's climate guidance already expects federally regulated financial institutions and their borrowers to disclose emissions. Whether the driver is a US rule, a Canadian standard, an investor or a lender, the underlying requirement is the same.

For real estate specifically, the pressure also comes from investors. The 2026 GRESB real-estate standard rewards portfolios that report actual metered data across their assets and scores estimates lower. In other words, clean bill and meter data is now worth points, not just peace of mind.

Choosing and documenting your emission factors

Activity data is half an inventory. The other half is the factor you multiply it by, and that is where two teams holding identical bills produce different numbers. A factor is specific to three things: the fuel or grid it describes, the geography, and the year. Canadian electricity makes the geography point obvious, since a kilowatt hour in Quebec and a kilowatt hour in Alberta carry very different emissions. A national average misstates both.

• Pick the published factor set you will use and name it, for example Environment and Climate Change Canada's emission factors and reference values, and record the document version each figure came from.
• Use the provincial electricity factor rather than a national average, and keep fuel factors separate from electricity factors.
• Record the vintage. Factors are published by year and revised, so a number with no year attached cannot be reproduced later.
• Expect restatement. When a factor set is updated, a defensible inventory can recalculate prior years on the new basis and show both.

The current Canadian electricity and natural gas factors, with the table each one comes from, are set out in calculating GHG emissions from utility data. How a grid factor is built, and why it moves year to year, is covered in electricity emission factors explained.

Location-based, market-based, or both

Scope 2 has two accepted methods and they rarely agree. The location-based number uses the average intensity of the grid you draw from. The market-based number reflects what you contractually bought, through a supply contract or renewable energy certificates. Under the GHG Protocol Scope 2 Guidance, an organization holding contractual instruments reports both, which is why disclosures often carry two Scope 2 lines that differ substantially. Neither is the honest one and the other the flattering one. They answer different questions, and the comparison is set out in market-based versus location-based Scope 2.

From bill to inventory, step by step

1. Collect every bill and meter across the portfolio, including gas, electricity and any district steam or chilled water.
2. Extract consumption by meter and period, normalized to consistent units, and validate it against the bill totals so a transcription error cannot inflate a number.
3. Apply location-based and, where relevant, market-based emission factors for electricity, and direct factors for on-site fuels.
4. Roll up by building, region and organization, with the underlying bills linked so the number is auditable.

What makes the number defensible

Assurance, a lender's diligence request and an internal restatement all ask the same question in different words: where did this figure come from? An inventory answers it when every number can be walked backwards.

• Every consumption figure traces to a specific bill or meter read, with the period it covers.
• Meter coverage is complete and stated, including which tenant or leased spaces are in or out, and why.
• Periods reconcile to the calendar year rather than to whatever the billing cycle happened to be.
• Each factor is recorded with its source and vintage, so the arithmetic can be reproduced.
• Estimates are labelled as estimates, with the method noted, rather than blended invisibly into measured data.

The difference between a defensible inventory and a shaky one is almost always the data layer. If the activity data is clean and traceable back to the source bill, the rest is arithmetic. If it is hand-keyed from PDFs, every figure is a question waiting to be asked in assurance.