retrieve the predicted marginal operating emissions rate (MOER) forecast for a grid region using the WattTime API v3 /forecast endpoint
domain: api.watttime.org · 6 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Register for a WattTime account and obtain OAuth2 bearer token credentials
Call /v3/my-access to confirm which regions and MOER model versions your account tier can access
Call /v3/forecast with a region abbreviation and signal_type=co2_moer to get the current forecast window
For a specific past forecast vintage, call /v3/forecast/historical with a start/end date range instead
Parse the returned point_time and value fields to schedule flexible loads during low-MOER periods
Track WattTime's periodic model version updates, since forecast values can shift when a new model version becomes default
Known gotchas
Free/lower-tier accounts have limited region and forecast-horizon access compared to paid tiers — confirm entitlements via /v3/my-access before assuming full coverage
Forecast values are model-version-dependent; comparing forecasts pulled before/after a model version update can show discontinuities unrelated to actual grid changes
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