California energy sources, use (IMAGE) DOE/Pacific Northwest National Laboratory Caption California uses energy from other sources, such as natural gas generators (their largest source of energy right now), lithium-ion batteries, and other states’ energy surplus, to augment what is lost. However, as more energy storage assets are dedicated to this service, the duration requirements increase as the remaining peak becomes flatter and longer. ( Credit Animation by Stephanie King | Pacific Northwest National Laboratory Usage Restrictions PNNL credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.