The Chilean Transmission Companies Association commissioned ISCI and SPEC to identify what transmission and storage infrastructure the national grid needs to support decarbonization, as renewables enter at scale and coal plants leave the system.
What sets this study apart from a standard planning exercise is that it calibrates the model to reproduce the constraints and costs the system faces today, and only then projects forward. The result is not a list of desirable works but one that starts from actual operation.
The deficit already exists
The central finding is that the gap is not a future one. Chile's grid already carries a transmission capacity deficit of around 3,000 MW, spread across the system, and it would persist to 2030. It breaks down into 2,000 MW of additional capacity and 1,000 MW of a flow control system between the North and Centre zones. Closing it would cost on the order of USD 900 million.
Looking further out, the study anticipates the need for a new HVDC link by 2036.
Batteries in the north do not replace the line
This is the least intuitive result. Deploying storage for arbitrage and ancillary services does reduce the need for transmission temporarily, but over the long run more battery capacity encourages new solar investment in the north, which loads the network again. The net effect is that more BESS in the north does not — or only marginally does — reduce the need for transmission works.
Planning under uncertainty
The report compares a stochastic approach, which explicitly internalises long-term uncertainty in the investment decision, against the classical deterministic one. It concludes that stochastic planning yields more robust and adaptive plans, and discusses how to set headroom margins to face that uncertainty efficiently.