Reliability of net-zero energy systems for South Wales

Wales is committed to meeting the Net-zero emissions target by 2050. To meet this challenge unprecedented changes in the energy system are required in South Wales. There are various pathways to achieve net-zero emissions in South Wales. These pathways are usually compared based on their costs. However, energy supply reliability assessment is required to determine the security of these scenario pathways. A probabilistic dynamic reliability assessment framework is proposed, which combines the Improved Universal Generating Function and the Improved Fisher optimal algorithm. This technique reduces the computational burden of reliability assessment by 95% with a similar accuracy compared with Monte Carlo Simulations. The impacts and sensitivities of energy sources and technologies on supply reliability in High Electrification and High Hydrogen scenarios are measured. As the penetration level of local renewables increases five-fold in 2050 compared with 2020, Loss of Load Expectation increases from 3 to 10–12 h/year in High Electrification and High Hydrogen scenarios. In summer, the reliability of energy supply is more sensitive to changes in the assumptions on failure probabilities of energy conversion devices, whereas the system's reliability in winter is mainly impacted by the availability of imported energy to South Wales.