California Grid Staggers under Heatwave Loads

Over the past few days California's 500,000 Pacific Gas and Electric Company users were warned via social media of rotating outages from Tuesday as the state experiences record-breaking hot weather. Outages are a significant inconvenience to those affected, but the grid operator prefers to manage emergencies in a controlled manner rather than let it cause more serious, longer lasting disruption, according to information the system operator released.

California Independent System Operators (CAISO), which runs the state's electrical grid, posted an Energy Emergency Alert 3 from 5:17 to 8 p.m on Tuesday. PG&E said CAISO asked the utility to tell customers rotating outages lasting one to two hours were possible, but in the event careful load management just avoided having to resort to this measure.

State officials forecasted that the power load might be over 51,000MW, the highest demand that state energy sector has ever reached. Wildfires are adding to the seriousness of the situation. Over the past week, firefighters faced 14 large fires and numerous smaller outbreaks, resulting in four fatalities. They often happen in California in summer but recent years have been particularly difficult as the state faces a historic drought and the climate crisis makes the area hotter and drier.

At the CAISO’s request on Monday, four temporary emergency power generators deployed by the department of water resources in Roseville and Yuba City were activated for the first time since they were installed last year, providing up to 120 megawatts, sufficient electricity for 120,000 homes.

The state has faced energy supply issues for over a decade, despite its wealth. California’s power grid could fail with rolling blackouts if user demand overcomes supply. In recent months there have been several emergency alerts. The use of air conditioning in homes, businesses and offices is a significant factor, and the addition of EVs as transport adds more complications for utilities calculating power supplies. PG&E had warned 525,000 homes that they could be without power due to the overloading of the grid. Although the state has some excellent hydropower resources, the drought has dried up many reservoirs, reducing this source of electricity.

Since 2015, 58% of the state’s thermal power natural gas units, which add up to 6.5 GW, have been retired, while solar capacity has increased by 8.8 GW. The state has also added 2.3 GW of battery storage capacity. Overall though, the amount of dispatchable power is lower in 2022 than in the previous year. With the hydropower shortages due to drought, this is causing considerable problems for the grid operators.

The local authorities have been working on this problem since the August 2020 brownouts. CAISO, the California Energy Commission (CEC), and the California Public Utilities Commission (CPUC) have created resilience plans to deal with extreme weather hazards and fire risks. The analysis for the key summer months of July to September projects that contingency resources are needed of 1 GW in August and 3.5 GW in September.

The state needs to rapidly increase its generation to cover this emergency requirement. In June, the legislature passed a bill that could extend the operating lives of existing generating facilities currently scheduled for retirement. This will create an operational reserve with up to 5 GW of power capacity. The California governor, Gavin Newsom, signed legislation on Friday that could allow the state’s last remaining nuclear plant to remain open beyond its planned 2025 closure, which will allow PG&E the option to keep the Diablo Canyon plant open until at least 2030.