# “100% clean energy” may describe annual matching—not every hour.

A contract or certificate can balance annual volumes without describing the electricity physically serving a facility at a given moment.

Canonical: https://brightaifuture.com/guides/annual-clean-energy-matching
Format: guide
Source publication: Not established
Bright publication: 2026-09-19
Substantive update: None recorded
Evidence and review: Primary-source review completed 2026-09-19; Bright did not reproduce the cited research.

## Four words change the claim

Ask whether matching is annual or hourly, and global or regional. Annual global procurement can support clean generation while the facility still draws from a local grid with fossil generation in some hours. Hourly regional matching is a tighter claim, but it still needs metered load, generation and accounting rules.

## Procurement is not physical isolation

A power-purchase agreement or energy attribute certificate is a financial and accounting instrument. It should not be described as a dedicated physical supply unless the interconnection and metering establish that relationship. The useful comparison is not “clean or dirty” but which temporal and geographic claim the evidence supports.

## Limitations

Carbon accounting methods differ.

Hourly matching does not by itself resolve transmission constraints or marginal emissions.

Bright did not calculate emissions for any facility.

## Provenance and history

{
  "provenance": {
    "publisher": "Bright",
    "role": "Source-backed evergreen explanation; not a new scientific result"
  }
}

## Original sources

- [DOE report on AI and energy](https://www.energy.gov/sites/default/files/2024-04/AI%20EO%20Report%20Section%205.2g%28i%29_043024.pdf)
- [DOE Grid Talk: annual and 24/7 matching](https://www.energy.gov/grid-talk/articles/grid-talk-google-hopes-hasten-clean-energy-revolution)

## Continue exploring

- [Mäntsälä’s operating heat-reuse network](https://brightaifuture.com/discoveries/mantsala-data-center-heat)