The relationship of constraints cost and load factor: A evaluation for the improved ICRP method

In the UK, Ofgem, launched Project TransmiT to make an independent review on the charging arrangements of electricity transmission networks. One main proposal is the improved ICRP method for TNUoS charges. Improved ICRP method takes historical annual load factor to represent the year round performance of system users. However, it is widely suspected whether load factor can effectively reflect the TNUoS charge that one should pay. In this paper, the relationship between annual constraints cost and generator load factor is explored to evaluate the improved ICRP method. A reduced GB power system is employed for system simulation. The results clearly show that both constraints cost and load factor are shaped by many factors and the relationship between them is not linear. So, it is inappropriate to use load factor for TNUoS charging. Furthermore, a similar method with National Grid's Constraints Analysis Tool is used to verify the findings.