Introduction This beta dataset provides carbon intensity insights by Grid Supply Points (GSP) across UK Power Networks’ licence areas. It shows blended carbon intensity values for each half-hour period, helping users understand how the carbon intensity of energy varies over time and across different parts of our network. Methodological Approach Plant Information (PI) tags and values associated with generators are matched to the relevant GSP, across Eastern Power Networks (EPN) and South Eastern Power Networks (SPN), via the Embedded Capacity Register (ECR), (over 1MW only). Generator fuel types are classified using the ECR's Energy Source and Energy Conversion Technology fields, with fallback logic applied where ECR data is missing (e.g., inferring fuel type from customer name). Fuel types are then mapped to published carbon intensity factors (gCO₂/kWh) provided courtesy of NESO (National Energy System Operator). For the purposes of this beta methodology, Batteries/BESS are assigned a carbon intensity factor of 0gCO₂e/kWh. This is a simplifying assumption and may be reviewed in future iterations, as battery discharge may reflect electricity previously imported from or generated elsewhere on the system. Using the PI values, carbon intensity at the DNO (Distribution Network Operator) level (without transmission network data) is calculated using a modified equation of the original methodology provided by NESO: DCt = Σ G g=1 Eg,t × Cg Eg,t Where: DCt is the DNO-level carbon intensity, in grams of CO₂ per kilowatt hour (gCO₂e/kWh), G is total number of generators, g is the individual generator, Eg,t is the energy export of the distribution-connected generator onto the distribution network at time t in kilowatt hours (kWh) and Cg is the generator’s corresponding carbon intensity factor in gCO₂e/kWh. We divide by the sum of Eg,t because the calculation produces a GSP-level generation-weighted carbon intensity. This calculation is performed separately for each GSP and half-hour period. Each generator’s contribution is weighted according to its exported energy during the half-hour period. Transmission import/export is accounted for separately in Equation 2. Network losses and sensitivity factors are not applied in this beta methodology. PI values are recorded from the PI server in MW. Our data is half-hourly, and thus, these values are converted to kW by multiplying by 1000 and then multiplying by 0.5 for kWh. Where multiple PI readings exist within a half-hour period, the average MW value is calculated first, then converted to kWh. Super Grid Transformer (SGT) header data is then added to the dataset. The SGT active energy value represents the net energy flow at the transmission-distribution boundary: positive values indicate energy flowing from transmission into the distribution network (import), while negative values indicate energy flowing from distribution back to transmission (export). The blended carbon intensity formula extends the original NESO formula to incorporate the transmission contribution:  BDCt = ((Eg,t × DCt) + (ESGT,t × Ct)) (Eg,t + ESGT,t) Where:Blended DNO carbon intensity, BDCt, at time t is calculated using the generation-weighted average carbon intensity of DNO generation, DCt, the SGT import/export energy, Esgt,t, and the NESO regional carbon intensity forecast, Ct. The SGT value represents the net energy flow at the transmission-distribution boundary during the half-hour period. Where SGT active power is recorded in kW, it is converted to kWh by multiplying by 0.5 hours. This formula is applied with the following assumptions: If sgt_energy_kwh is positive, the interval is treated as data available, and blended carbon intensity is calculated as a weighted average of local DNO generation intensity and the NESO regional carbon intensity forecast, weighted by their respective power contributions. This reflects the transmission network supplementing local generation to meet demand. If sgt_energy_kwh is negative but dno_generation_kwh + sgt_energy_kwh > 0, the interval is treated as data available, and the blended carbon intensity is set to the local weighted average carbon intensity only. The NESO forecast is disregarded because the DNO network is a net exporter - local generation exceeds demand and the surplus is flowing back to the transmission network, so no transmission network-sourced power is entering the distribution network. If sgt_energy_kwh is negative and dno_generation_kwh + sgt_energy_kwh <= 0, the interval is treated as no data available, and the blended carbon intensity is set to null. This occurs when the volume of power being exported to transmission network exceeds total visible DNO generation, suggesting either unmetered generation, data quality issues, or load flow conditions that cannot be reliably attributed to a carbon intensity value; and If sgt_energy_kwh is null, the interval is treated as no data available with no transmission network data available. Without SGT data, the transmission network contribution to demand cannot be quantified and a reliable blended carbon intensity cannot be calculated.Limitations and ConsiderationsDNO generation visibility is limited to generators registered in the ECR and matched via PI tags. Unregistered or unmetered embedded generation is not captured.The NESO regional carbon intensity forecast is used as a proxy for the carbon intensity of power imported from the transmission network. This is a regional average and may not precisely reflect the marginal generation mix at the specific GSP.Quality Control StatementQuality control measures include:Automated review to check PI tag status; andMonthly upload of new ECRAssurance StatementThe Open Data Team, DSO Data Science Team, and the DSO Regional Development Team worked together to ensure data accuracy and consistency.OtherDownload dataset information: Metadata (JSON)Definitions of key terms related to this dataset can be found in the Open Data Portal Glossary: https://ukpowernetworks.opendatasoft.com/pages/glossary/To view this data please register and login.