In 2022 wind and solar supplied 28% of the energy generated in the Chilean National Electric System (SEN), and the Long-Term Energy Planning 2023-2027 projects close to 60 GW of solar and wind capacity for a generation mix consistent with carbon neutrality by 2050. This report answers the question that leap leaves open: what stops us today from making good use of existing transmission, and what has to change to plan the transmission still to come.
This is the final report of the study, prepared by SPEC and the Instituto Sistemas Complejos de Ingeniería for Generadoras de Chile and Transmisoras: 141 pages across four modules —short, medium and medium-to-long term, plus regulation— with the modelling detail, the simulations on the SEN and three technical annexes.
Operation today
- Transfer control is manual. Inter-zonal dispatch and marginal cost during congestion follow the National Electrical Coordinator's Operational Instructions Registry, and the Coordinator issues instructions on a simplified version of the system. On the Nueva Pan de Azúcar – Polpaico corridor in 2022 there were many hours of use close to the 2,000 MVA capacity of the Polpaico substation, but also events with lower transfers and marginal cost decoupling that was not duly justified, which hits those subject to curtailment.
- Coal inflexibility lies in its start-up and shutdown costs, modelled as cold starts; the Australian benchmark shows significantly lower values for warm or hot starts. Even so, making them flexible achieves little: the curtailment projected as solar advances implies an oversupply of energy in solar hours above demand, particularly in the second half of the year.
Planning and its regulation
Current methodology assesses projects candidate by candidate. The report concludes that the process must move to advanced optimization models —already used by planning authorities in the United Kingdom, Australia, France and China— and adopt a multi-value approach to benefits, illustrated with an application to the Chilean system.
The review of the General Law of Electric Services and of the transmission planning regulation finds a pervasive lack of methodological detail on modelling and input data. To harmonize both sectors, the proposal has three lines: financial network contracts, modernization of the regime for merchant transmission investment, and remuneration of expansions through tariffs charged to beneficiaries.