According to the same source:<p>&gt; In 2014, less than 5% of California&#x27;s total energy demand was served by coal and petroleum coke-fired plants, nearly all of it from plants outside the state<p>Which is followed by what you quoted:<p>&gt; At times...<p>So, according to that source, out of state coal consumption can range from 5% to 50%. It doesn&#x27;t say exactly <i>when</i> the 50% figure was hit, or why.