Optimal annual decarbonisation pathways to 2050 considering capacity and operational dispatch requirements, and current policy momentum effectsETI commissioned Baringa to undertake detailed analysis of what the cost optimal power sector capacity mix could look like around the 2030 point on the pathway to 2050, which allows for feasible operation (in line with GB’s reliability standard for a loss of load expectation of 3 hours per year) and which is consistent with a trajectory that enables the UK to meet its longer term, economy-wide emissions target.The analysis was undertaken in PLEXOS using the LT Plan (Long-Term) functionality that is available. A model was developed that minimises the total costs (capital, fixed operating and variable operating costs) of generation while ensuring the security of supply and meeting the carbon targets. For existing capacity we have used our detailed in-house generation database that includes all power plants that participate in the wholesale markets along with their operational characteristics.The plant retirement decisions are an exogenous input to the model.The costs of new entry capacity were mainly advised from the ESME database while the operating characteristics were a combination of ETI data supplemented by additional Baringa information where relevant (e.g. ramp rates or start costs for more detailed operational analysis which are not present in the ESME database). Fossil fuel prices were based on near term forward prices and International Energy Agency’s (IEA) long-term projections as the most recent available set of assumptions. A carbon intensity target was set at 90gCO2/kWh for 2030 and to net zero carbon emissions for 2050 (linear interpolation in between)We simulated the GB power market for the horizon of 2022 to 2050 using the inputs described above.The simulation was run on annual basis with a reduced chronology (6 sample days per year with hourly dispatch and representation of interconnected market prices from Baringa’s pan-European power model). In the period 2022-2030, all coal and some older gas plants are decommissioned.The carbon intensity target remains high during that period and many technologies such as CCS and Nuclear remain expensive. As a result most of new capacity deployment comes from CCGT.Most of the peaking capacity requirements for that period are met by OCGTs. In the period 2030-2050, carbon intensity target drops significantly and therefore there is need for more low ca...