Integrating base-load cycling capacity margin in generation capacity planning of power systems with high share of renewables

Abstract

The coordination between the renewable energy integration scale and the cycling capacity adequacy of power systems has been largely ignored at the capacity planning stage. In this paper, a generation capacity planning model (GCPM) for power systems with significant renewable energy is proposed taking into account the base-load cycling capacity margin (BCCM). In this model, the daily feasible ranges of system minimum output in the target year are given. For a day in the target year, if the sum of minimum load and BCCM does not reach the feasible range, then the BCCM constraint of that day is introduced into the GCPM to re-optimize the generation capacity mix. This treatment is conducted for each day to make sure the daily BCCM constraints can be satisfied in the capacity planning stage. Moreover, the impact of the CO₂ emission cost on the optimal generation capacity mix is also addressed. The model is solved by combination of the screening curves method and Lagrange relaxation method. Numerical simulations are presented to verify the reasonableness and effectiveness of the proposed model. As compared with the traditional GCPM without BCCM constraints, the capacity shift from base-load plants to mid- and peak-load plants increases significantly with the increase of renewables after considering the BCCM constraints. It confirms that the BCCM constraints are non-negligible in GCPM, especially for power system with high share of renewable energy.