Expansion planning studies of generation sector in highly renewable energy systems considering flexibility requirements

This is the authors' abstract. We don't add key points for this paper.

• Assessing the bond between the power system flexibility status and the level of power system CO 2 emissions. • Investigating the CO 2 emission constraints effects on the power system optimal generation mix. • Putting forward a GEP model that maintains the power system flexibility while lowering CO 2 emissions from thermal units. • Suggesting a low carbon power system RERs expansion plan. This work focuses on the development of a decarbonization-based generation expansion planning (GEP) model taking into account short-term operational constraints. In this planning model, two different criteria are developed to properly evaluate the relationship between the CO 2 emissions in generation sector of renewable-based power systems and the flexibility requirements. Mixed integer linear programming method is deployed to run the decarbonization-based GEP model proposed in this work. Also, to develop the decarbonized power system, CO 2 emissions cost is incorporated into the objective function of the model, and flexibility sufficiency of the power system is ensured using integration of short-term operational requirements in the model. Results show that applying the CO 2 emissions cost in the objective function of expansion planning studies lead to changes in generation mix and significantly increases the penetration of renewables in the power system. Also, the implementation of stringent approaches, such as the immediate prohibition of flexible generation units expansion, does not lead to effective results in reducing CO 2 emissions throughout the planning horizon. Finally, banning the development of flexible generation units, significantly increases the risk of lack of flexibility in the power system.