Necessity of Joint Resource and Transmission Expansion Planning in Presence of System and Policy Uncertainties

A clear gap exists between the way that power system expansion planning is modeled in academic research papers and the real-world practice of system planners. To address this gap, we perform two comparative numerical case studies on a large-scale ERCOT-like test system. In the first study, we quantify the economic benefit of optimization-based TEP over the approach of project-by-project screening of expansion plans that is more popular in industry. The second study compares the solutions of resource-only expansion planning with those of joint resource and transmission expansion planning considering four future scenarios representing uncertainties that exist in emission reduction policies and forecasted demand. Numerical case studies illustrate the significant economic and technical benefits of co-optimization in resource and transmission expansion planning.