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Carbon

See which app is drawing the most power right now, and what that costs in carbon

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About Carbon

Carbon is built to make energy use visible per app. It reads per-process CPU time through proc_pidinfo, maps it to estimated watts against a TDP chosen by your chip's tier, adds estimates for GPU and display, and converts the total to emissions using a built-in table of national carbon intensities. The interface is a per-app breakdown sorted by draw, a weekly chart through Swift Charts, and suggestions written to be acted on when an app draws more than a few watts. History lives in SQLite, totaled as kWh and CO2 equivalent. Every figure is an estimate, and the app is built to say so.

Who it's for

Environmentally conscious Mac users who want to understand and reduce their energy footprint.

What it does

  • Per-app energy estimation in real-time watts
  • Chip tier detection to pick a TDP
  • GPU and display power estimates via IOKit
  • Carbon intensity (gCO2/kWh) for 47 countries
  • A weekly energy chart via Swift Charts
  • Suggestions for cutting energy waste
  • Flags any app drawing more than 5 W

Behind the build

Carbon estimates each app's watts from CPU time: every 5 seconds it reads proc_pidinfo, converts the Mach ticks with mach_timebase_info, and scales each app's CPU share by a tier-based TDP for the chip.

GPU power comes from IOAccelerator's PerformanceStatistics utilization, split heuristically across GPU-heavy apps, and carbon intensity from a built-in table of national averages for 47 countries. The model is rougher than it has to be: since macOS 13 the kernel keeps its own per-process CPU energy estimate, ri_energy_nj in proc_pid_rusage, and on an M5 Max the energy per CPU-second varied five to seven times between apps where Carbon assumes one rate for all.

The full write-upPer-app power on Apple silicon: Mach ticks and ri_energy_nj

Information

Runs on
macOS · Menu bar
Status
Source only
Requires
macOS 14+
Source
Public on GitHub
Telemetry
None
Built with
Swift & SwiftUI
Stack
SwiftUIMach APIsIOKitSQLiteSwift Charts

Works well with

  • BatteryBuddy

    BatteryBuddy tracks battery health, Carbon tracks energy consumption

  • Afterburn

    Afterburn optimizes CPU usage, Carbon shows the energy savings

Carbon is source only, for now.

The code is public, but there's no packaged release yet. Build it from the repository today, or leave an email and hear when there's one you can double-click.

Tell me when it shipsView source

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