Generation Expansion Planning Considering the Rehabilitation of Aging Generating Units

Aging generating units can gradually lose their efficiency, reliability, and economic viability, and violate certified levels of carbon emission in power system operations. Retirement is traditionally considered a viable option for managing aging units within the generation expansion planning (GEP) studies; while, the rehabilitation of such units can also be economically beneficial to power system and even outperform other options considering certain planning and operation criteria. Rehabilitation procedure depends on many physical factors including generating unit types and locations, as well as financial, regulatory, and transmission network constraints. This paper presents an optimization model for GEP considering retirement and rehabilitation options for generating unit planning and operation. The proposed GEP problem uses the Conditional Value-at-Risk (CVaR) as a risk index for considering rehabilitation cost and load forecast uncertainties. In order to evaluate performance of the proposed method, the IEEE 24-bus and 118-bus systems are examined in various operating conditions and the results are analyzed.