Software Carbon Intensity

A SoftwareCarbonIntensity property references a published Software Carbon Intensity (SCI) score or methodology document for an API or service. SCI is an ISO-ratified standard from the Green Software Foundation quantifying carbon intensity using the formula SCI = ((E * I) + M) per R — where E is energy consumed, I is the marginal carbon intensity of electricity, M is embodied carbon, and R is a functional unit such as per API call or per user. Publishing an SCI score makes carbon efficiency measurable and comparable across API providers.

Also known as: SCI, SCI Score

Example

- type: SoftwareCarbonIntensity
  url: https://developers.example.com/sustainability/sci

Standards

Green Software Foundation Software Carbon Intensity (SCI) Specification
Green Software Foundation SCI Specification source
ISO/IEC ISO/IEC 21031:2024 — Software Carbon Intensity (SCI) specification
Green Software Foundation Green Software Foundation Principles of Green Software Engineering
GHG Protocol / WRI / WBCSD GHG Protocol Product Life Cycle Standard

Media Types

application/json — Machine-readable SCI score and component breakdown.
application/yaml — Impact Framework manifests describing SCI pipelines.
text/markdown — Methodology and reasoning published alongside the score.

Governance Rules

sci-formula-disclosed (SCI Specification) — The SCI score must be derived from ((E * I) + M) / R, not arbitrary aggregation.
sci-marginal-not-average (SCI Specification) — I should reflect marginal carbon intensity where data is available, not annual averages.
sci-embodied-amortized (SCI Specification) — M (embodied carbon) is amortized across the hardware's useful life and reservation share.

Risk & Compliance

Compliance:

CSRD / ESRS E1 — product carbon footprint disclosures
Customer Scope 3 Category 1 (purchased goods and services) reporting on SaaS usage

Security: An SCI score without disclosed inputs is unverifiable; cite electricity-mix data provider, hardware embodied-carbon dataset, and the measurement boundary so the number is reproducible and defensible.

Tools

Green Software Foundation Impact Framework — SCI calculation (MIT)
Impact Framework source — SCI calculation (MIT)
Cloud Carbon Footprint — Cloud energy and emissions estimator (Apache-2.0)
Kepler — Kubernetes energy metering (Apache-2.0)
Scaphandre — Power-consumption metrology (Apache-2.0)
Electricity Maps API — Marginal carbon-intensity data feed

Suggested Metrics

sci_score — ((E * I) + M) / R — the core SCI number.
energy_per_request_wh — E component normalized to a single API request.
carbon_intensity_g_per_kwh — I — marginal grid intensity for the region serving the workload.
embodied_gco2e_amortized — M — amortized share of hardware embodied emissions attributable to the workload.
requests_per_score_window — R — functional-unit count over the measurement window.

Example Implementations

Green Software Foundation — Specification, formula derivation, and reference case studies.
GitHub — Green Software Foundation work and tooling discussions hosted publicly on GitHub.

Related Properties

Sci report
Ghg protocol report
Sustainability