Supply-side capacity in the NEM over the next 24 years (v2)

The 2026 Integrated System Plan projects electricity supply across the National Electricity Market to 2050 under three scenarios. The work categorises generation into bulk energy (variable renewables), firming (including Snowy 2.0 and Borumba pumped hydro), and shaping services. The optimal development pathway was tested across Slower Growth, Step Change, and Accelerated Transition futures, as well as a sensitivity case modelling constrained delivery of generation and transmission infrastructure. The analysis extends the ISP's generation development outlook across 24 years under different assumptions about economic growth, climate policy stringency, and the pace of infrastructure build.

Where this fits

This frames the cost and reliability question at the core of the energy transition. The ISP assumes delivery of firming capacity (pumped hydro) alongside variable renewables to meet demand and net-zero targets. But the constrained-delivery sensitivity, testing what happens when infrastructure build slows, directly probes the grid's vulnerability to the supply-chain, permitting, and transmission delays already evident in Australia. It also reveals the plan's dependence on two large firming projects rather than firm, dispatchable generation that carries no delivery risk and no weather dependence.

What it means

If Snowy 2.0 and Borumba slip, the NEM's pathway to 2050 fractures. Pumped hydro depends on capital intensity, long lead times, and complex environmental approvals. A nuclear alternative, banned by law but lowest-emission and firm, would decouple the decarbonisation task from the bet on two projects. Australia's grid plan is credible only if these firming assets arrive on schedule. The ISP does not test that assumption hard enough.