Time-Varying Grid CO2 Emission Factors Derived from TSO-Level Generation Mix in Japan

Description This dataset provides hourly (1-hour resolution) grid carbon intensity values for fiscal year 2024 (April 2024–March 2025), calculated based on the electricity generation mix within the service areas of the nine Japanese transmission system operators (TSOs):- Hokkaido Electric Power Network- Tohoku Electric Power Network- TEPCO Power Grid- Chubu Electric Power Grid- Hokuriku Electric Power Transmission & Distribution- Kansai Transmission & Distribution- Chugoku Electric Power Transmission & Distribution- Shikoku Electric Power Transmission & Distribution- Kyushu Electric Power Transmission & DistributionThe grid carbon intensity presented in this dataset represents CO₂ emission factors (kgCO₂/kWh) that vary over time in response to changes in the observed generation mix under prevailing operating conditions. The dataset is constructed using publicly available TSO-level hourly electricity generation data for FY2024, together with fuel-specific CO₂ emission coefficients. For each TSO service area, electricity generation by fuel type is aggregated at an hourly resolution, and grid carbon intensity is calculated as the weighted average of fuel-specific emission factors. The resulting time series captures short-term variations in grid emissions arising from renewable generation variability, thermal dispatch adjustments, and operational constraints. The data are provided as separate CSV files for each TSO, with timestamps formatted in ISO 8601 and explicit time zone offsets. This dataset is intended to support urban- and regional-scale energy and emissions analyses, including demand-sensitive carbon accounting and spatio-temporal comparison of grid emission characteristics. In addition to the primary grid carbon intensity data, the dataset also includes auxiliary time series data, provided for transparency and reference, consisting of TSO-level electricity demand, fuel-wise electricity generation, and fuel-wise CO₂ emission equivalents derived from lifecycle-based emission factors.