Cali Went Too Sunny

California’s Senate Bill 100 requires renewable energy and zero-carbon resources to supply 100% of the state’s electric retail sales by 2045. It is now common to find homes topped with solar panels across the Golden State. However, solar production now sometimes exceeds the demand, particularly on sunny spring days when air conditioning use is low. To avoid grid overload, when excessive electricity supply occurs, solar farms have to be temporarily shut down, or the neighboring states have to take the energy- through the Western Interconnected System. The excessive electricity was often exported to Arizona and Nevada. 

Photo credit: Glen Richard 

Lately, the renewable energy wasted has skyrocketed from oversupplying what the grid can carry. The state plans to install additional storage/ batteries to hold the electricity until later in the afternoon. Furthermore, the state has changed its net-metering system: rather than paying rooftop solar owners $0.20 to $0.30 per kilowatt-hour for exported electricity, they are now compensated based on the grid’s demand- meaning that it can dip close to zero when supply exceeds demand. 

The Western Interconnected System also includes British Columbia and Alberta, along with 14 U.S. states. California, Oregon, and Washington are BC’s biggest trading partners- while selling to California the most and buying from Washington the most. Trading electricity enables purchasers to choose from the lowest-cost supplier and to spread the risk in case any generation sites go down. Participating in the Western Interconnected System also enables BC to meet peak electricity demand during cold days without needing to build excessive electricity generation plants. 

Most of BC’s electricity is hydro-generated, but drought conditions have reduced the inflow to hydro dams. In 2023, BC Hydro imported nearly double the electricity compared to the previous year to offset lower hydro production. With 2024 likely being a low water year, BC Hydro is planning to import additional power through Powerex.