Abstract: As a result of the establishment and implementation of national “dual-carbon” targets, new energy consumption problems continue to intensify. Reasonable construction of pumped storage power stations can provide strong support for the safe and stable operation of the power system. However, due to significant difficulties such as construction expensively, significant impact on regional electrical power development and lack of relevant studies, it is urgent to necessitate the conduct of demand sizing and economic measurement for pumped storage, thus filling the theoretical gaps in China and providing technical support. Therefore, the actual planning scheme and development status quo of the Hunan power grid are used as the basis; the techno-economic and technical characteristics of thermal power, gas power, external power, and pumped storage within the provincial power system are comprehensively considered; a complete set of calculation methods linking pumped storage grid demand and new energy consumption is proposed; and corresponding power development programs are formulated to ensure power supply reliability and enhance new energy integration. By comparing the economic benefits and coal-saving benefits, a reasonable scale of pumped storage demand in the target year is derived, and corresponding suggestions are made for the medium- and long-term power supply preservation of provincial power grids.