In terms of sourcing high-quality open data, Climate TRACE offers very detailed open data about emissions from millions of asset locations across the world. Go to Data Downloads - Climate TRACE | Climate TRACE to find out about the data downloads and API.
Global Energy Monitor also offers fantastic open data on the energy system and energy companies - including the Global Energy Ownership Tracker.
Global Energy Monitor are a Climate TRACE partner so this ownership data is reused on the Climate TRACE platform. Here is a recent blog post explaining how to make use of this ownership data for emitting assets.
Global Energy Monitor are a member of the Global Open Data Integration Network which I help to convene. This calls on organisations to use the Legal Entity Identifier in more global datasets to uniquely identify companies to improve interoperability and allow linking between datasets more easily.