CH column metadata: default.operational_data.energy

# `default.operational_data.energy` Energy value. Units depend on `energy_magnitude` and `source_interval`. See CLAUDE.md §'Energy Units' table for the conversion rules — never sum across rows with different (energy_magnitude, source_interval) without normalizing first. - **unit**: varies (MWh or MW; per row metadata) - **common_pitfalls**: - BS rows: energy_magnitude='MW' (power, not energy). Multiply by 0.25 or 1.0 to get MWh depending on source_interval. - STARTUP_GAS_*: energy=0 always; cost in `price` column