How 85% is the new 35% for power systems planning
It seemed like yesterday when even considering an 85% renewable power system was considered too ambitious, too forward-looking, or downright impossible. Sure CAISO just hit 99.9% renewable for a short period, but reaching 85% over an entire year is a different story. When I first started analyzing renewable integration our "high renewables" scenario evaluated a 30% wind and solar grid.
Things have certainly changed. Battery storage may be the key enabler, but there's a lot of other things that have happened as well. The technology has improved and our inverters are more sophisticated. Utilities and ISOs have learned to leverage inter-regional balancing and interchanges.
Our recent study, Reliably Reaching California's Clean Electricity Targets: Stress Testing Accelerated 2030 Clean Portfolios, leaned into these trends and evaluated a suite of portfolios that accelerated the state's renewable transition.
We developed three portfolios reflecting different renewabl e build outs and electrification levels that meet an 85% clean electricity target by 2030. These portfolios were tested in an operational model (PLEXOS) that steps through every hour of the year to see if the future clean system can serve load across a range of conditions. The study incorporated many years of weather data and exercised the system through various stress conditions (such as retiring some in-state gas, low hydro availability, west-wide coal retirements, and mimicking the August 2020 heatwave conditions).
Our analysis finds that it is possible to reliably meet an 85% clean electricity target across these conditions.