The Northwest Power and Conservation Council recently released a report titled “Pacific Northwest Adequacy Assessment for 2029” (Adequacy Assessment). The Adequacy Assessment provides five reliability metrics, and under the Base Case scenario the system “passes” each one. With a different set of demand assumptions, the system “fails” on all five metrics. There is a lot to unpack in the report. Based on Energy GPS’ modeling of the PNW system, coupled with our analysis of this report, the odds appear to be in favor of sufficient reliability in 2029.

Figure 1 | Pacific Northwest Power Supply Adequacy Assessment for 2029

Before digging into some of the details of the Adequacy Assessment, it is first useful to put this report into context. The 1980 Pacific Northwest Electric Power Planning and Conservation Act authorized the states of Idaho, Montana, Oregon, and Washington to form the Northwest Power and Conservation Council (Council). In the intervening years, the Council has developed top notch grid modeling capabilities. Effectively and accurately modeling the hydro system poses a unique challenge, and Council staff has been working for the better part of a decade to both better represent the hydro system in its stochastic models and to develop an array of metrics which convey reliability risks in a clear and understandable way. One of the fundamental challenges with hydro modeling stems from the fact that hydro is the original intermittent resource – the volume of water is uncertain and can change by year, season, and month. Broadly speaking, the PNW hydro system, coupled with other thermal and renewable resources, has sufficient nameplate capacity to meet demand during the times of greatest need, but in low water years there is insufficient energy to do so.........