An open, harmonised dataset of 4,551 power plants worldwide that each carry an asset-level annual CO2 figure with explicit provenance - regulator-measured for the US (EPA GHGRP, 616 plants) and the EU (EU ETS, 47 plants), and modelled/inferred from Climate TRACE (3,888 plants, satellite observation plus inventory inversion) elsewhere, i.e. about 14% measured and 86% modelled - merged onto the WRI Global Power Plant Database backbone. Each record adds a normalised owner (95%), commissioning year (84%), derived emission intensities (per MW of capacity and per GWh of generation), national grid carbon intensity for context (99%), and an offline Koppen-Geiger climate class for every plant (100%). Coverage spans 29 of the world's largest power-emitting countries; total about 8.7 Gt CO2/yr. Read the co2_source field before interpreting CO2: most values are modelled estimates carrying real per-asset uncertainty, so relative rankings are robust while absolute values are model-grade. Accompanying files include ownership-concentration.csv, climate-zone-emissions.csv, a data dictionary, datapackage.json (Frictionless) and a data descriptor. All inputs are CC BY 4.0 or public domain; the release is CC BY 4.0.