California just made greenhouse gas reporting mandatory for the first time. On February 26, CARB unanimously approved regulations under SB 253, requiring companies with over $1 billion in revenue to publicly report their emissions starting August 10, 2026.
If you manage commercial buildings in California, you probably don’t have to file anything. But your tenants might — and when they do, they’re going to need data from you.
What’s happening
SB 253 requires large companies doing business in California to report Scope 1 and Scope 2 greenhouse gas emissions annually. Scope 2 covers emissions from purchased electricity and natural gas — the energy your buildings consume every day.
The threshold is $1 billion in revenue, which means the companies affected are your major tenants: Fortune 500 corporations, large law firms, tech companies, financial services firms. These are the tenants leasing significant space in your buildings.
Why this lands on your desk
Most building owners fall well below the reporting threshold. But here’s the catch: your tenants can’t report their Scope 2 emissions without your building’s energy data.
If your tenant pays their own electric bill, they have part of the picture. But they still need data on shared systems — the central plant, lobbies, garages, elevators — that run on your meters. And in many buildings, utilities are included in rent or paid entirely by the owner. In those cases, the tenant has nothing without you.
Starting in 2027, the requirements expand further. Tenants will need to report Scope 3 emissions, which includes the energy consumed in leased spaces they don’t own. That means even more detailed requests: whole-building consumption, allocation by square footage, and the emission factors used.
The bottom line: you’re not the filer, but you are the data source.
What tenants will ask for
Expect requests that look something like this — typically from your tenant’s sustainability team or an outside consultant:
- Whole-building electricity consumption (kWh) for the calendar or fiscal year
- Whole-building natural gas consumption (therms) for the same period
- Greenhouse gas emissions calculated using both location-based and market-based methods
- The tenant’s allocated share based on their leased square footage
The ask is straightforward. The challenge is pulling the data quickly and confidently, especially in split-meter buildings where you only see part of the picture.
How Gridium handles this
If you’re a Gridium customer, the data is already in your account.
Consumption data. We track electricity and natural gas consumption by building and by meter from your utility billing data. In split-meter buildings where tenants pay their own electric bills, we have the owner-paid meters covering base building systems — central plant, lobbies, garages, elevators. For whole-building totals, your tenant may need to combine our data with their own meter data, or you can request aggregated consumption from the utility under California’s benchmarking law (AB 802).
Emissions calculations. Our dashboards already calculate both location-based and market-based emissions — the two methods the GHG Protocol requires. Your tenant’s consultant doesn’t need to do the emission factor math. The numbers are there.
Flexible exports. Whether a tenant needs an annual summary, a monthly breakdown, or data in a specific format for their ESG platform, we can pull it.
When a tenant sends that data request, your Gridium energy manager can have the response ready within a day. No scrambling through utility bills, no calling the utility for historical data, no hiring a consultant to run the numbers.
What you don’t need to worry about
A few things that are not your problem:
- Filing the report. That’s on the tenant. You’re providing source data, not submitting anything to CARB.
- Scope 1 emissions. Things like refrigerant leaks and backup generators are the tenant’s responsibility to track for their own operations.
- Getting it perfect in year one. CARB has said that “good faith efforts to comply will be sufficient” during the first year. The data you have is the data that matters.
The bigger picture
Being responsive to tenant data requests isn’t just compliance support. It’s a leasing differentiator. As more companies face mandatory disclosure, the buildings that can produce clean energy data on demand will have an edge over those that can’t.
Green lease clauses requiring energy data sharing are becoming standard in institutional leases. Investor ESG due diligence increasingly asks about portfolio-level emissions. The trend is clear: building energy data is moving from a nice-to-have to a must-have.
Gridium customers already have it.
Have questions about how SB 253 affects your buildings? Reach out to your Gridium energy manager — we’re here to help.
