Simulation of operational reliability of thermal power plants during a power crisis: Are we underestimating power shortage risk?

The unscheduled outage of thermal power plants following the Great East Japan Earthquake in 2011 greatly degraded the reliability of the power supply. As thermal power plants were a major part of the supply capacity after the disaster, especially under peak load conditions, consumers located both within and outside the severely damaged area had to reduce power usage to meet power consumption targets and avoid major blackouts. Therefore, experts and decision makers should use the records available from such accidents to determine appropriate margins of supply capacity and demand constraint policy during a crisis. Here, we constructed a probability model describing the likelihood of accident occurrence for thermal power plants based on the actual accident and recovery data obtained after the Great East Japan Earthquake. The lognormal and Weibull hazard models fit the observed data well, where the accidents tended to occur for many times at the same power generation unit under heavy-duty conditions. We then applied the developed probability model to Japanese thermal power plants in a bootstrap framework to understand the potential risk of power shortages during such events and to derive policy implications.