According to California Independent System Operator (CAISO) figures, energy usage is down for week 14. Overall, weekday power usage was down roughly 4% as compared to the same time last year.

To balance the state’s energy demand, natural gas power is up nearly 1,400 megawatt hours (MWh). Meanwhile, renewables, batteries, nuclear, and coal power were virtually even as compared to the same time last year. Imports were down 130 MWh as compared to last year, and large hydropower was down more than 2,050 MWh.

Should the drop in large hydropower continue, California can expect a rise in energy costs according to a study by the University of North Carolina and North Carolina State University. The study looked at the impact of the 2012-2016 drought on California’s energy market. Traditionally, large hydropower accounts for 13% of the power supply. During the drought, large hydropower plummeted to 6% of the overall power supply. The researchers believe that the change forced the three investor-owned utilities to purchase additional power at a cost of $1.8 billion.