Abstract: Extreme weather events become more frequent because of climate change, posing a threat to the security and stability of the electricity system. Current researches about strategic reserve generation units mainly focus on policy evaluations or modelling simulations from the perspective of unit costs and power sale income, which do not adequately account for the economic and social effects they can bring. In order to comprehensively analyze the economics of strategic reserve generation units, a cost-benefit analysis model was established from the perspective of the whole society, considering the benefits including the guarantees for the economic production, health benefits for residents and labor force level, and the costs of strategic reserve generation unit investment and operation, and Sichuan power restriction event was taken as a case study for analysis. Results show that the benefit for 1 kW·h electricity that can be brought by the strategic reserve generation units is 4.77 yuan/(kW·h) and the required costs for 1 kW·h electricity generated by building new strategic backup units and using units that are close to retirement were about 1.91 yuan/(kW·h) and 0.47 yuan/(kW·h), respectively. Thus it is economically feasible to build and operate the strategic reserve generation units from the whole society perspective. At the same time, the operating hours are the most critical factor affecting the cost of strategic reserve generation units, and if the operating hours are less than 89 hours in a year, the unit's cost of electricity will be higher than its social benefits.