In 2022 wind and solar generation supplied 28% of the energy of Chile's National Electricity System, and the 2023-2027 Long-Term Energy Planning exercise projects close to 60 GW of solar and wind capacity —some 50 GW more than at the end of May 2022— for a generation mix consistent with carbon neutrality by 2050. This document is the summary of the study by SPEC and ISCI: what today prevents the existing transmission system from being used well and the future one from being planned well. It organizes its findings into four modules: operation, technologies, planning and regulation.
Current operation
Chile calculates marginal cost at more than a thousand nodes, but operates the system zonally: the Coordinator defines eight zones and controls transfers through manual instructions. On the Nueva Pan de Azúcar–Polpaico 500 kV line, 84% of the decoupling events logged in 2022 occurred with flows below 2,000 MW, under the thermal limit. On 27 January 2022, at hour 15, wind and solar curtailment exceeded 400 MW while the line had some 200 MW of remaining capacity.
Making coal flexible
Hourly unit commitment simulations for 2023, with a median hydrology of 23 TWh, put base-case wind and solar curtailment at 11.94% of annual wind and solar energy, around 5,000 GWh. Recognizing warm and hot starts brings it down to 9.67% and 9.54%; with the minimum inertia constraint —6,000 MVA from Maitencillo northward— only to 10.53% and 10.51%. The theoretical unconstrained case stops at 8.01%: there is a structural floor, because in solar hours renewable availability already exceeds demand.
Planning and regulation
The study proposes moving from candidate-by-candidate assessment to portfolio optimization, with a multi-value approach. MISO's Tranche 1 portfolio illustrates this: on production cost savings alone (USD 16.4 billion) its benefit/cost ratio was 1.05, not enough; with the remaining benefits it rises to USD 53.3 billion and to 3.4. The regulatory review concludes that the framework —the Electricity Law, the Transmission Planning Regulation and four other bodies of rules— does not specify modeling requirements or the treatment of input data. The proposed tariff reform has three axes: financial transmission rights (FTRs), a free investment regime alongside the mandated one, and beneficiary-based tariffs.