> In 2014, less than 5% of California's total energy demand was served by coal and petroleum coke-fired plants, nearly all of it from plants outside the state
Which is followed by what you quoted:
> At times...
So, according to that source, out of state coal consumption can range from 5% to 50%. It doesn't say exactly when the 50% figure was hit, or why.
Peak use vs. average use. A dramatic spike in usage means you need to get power from somewhere (or put up with brownouts), and on occasion that means 50% comes from coal even if it's only for 30 minutes a few times a month.
Stocks versus flows. You integrate power over time to get energy. 5% of the energy comes from coal but up to 50% of the power. That means that much of the time the use of coal power has to be less than 5%. Probably but not necessarily much less.
Power is the rate at which energy is flowing. You can get the same amount of energy by either a large amount of power for a short time or a small amount of power for a short time. A way you could have up to 50% coal power but only 5% coal energy is if you use 0% coal for power 90% of the time but 10% of the time use 50% coal power.
> So, according to that source, out of state coal consumption can range from 5% to 50%. It doesn't say exactly when the 50% figure was hit, or why.
The quote is from the Southern California Public Power Agency (SCPPA). Their members include LADWP, Anaheim, and other municipal power agencies. The 50% of which he speaks is, like others have noted, for demand (not energy), but only for SCPPA, not all of California. The < 5% is for all of California.
> In 2014, less than 5% of California's total energy demand was served by coal and petroleum coke-fired plants, nearly all of it from plants outside the state
Which is followed by what you quoted:
> At times...
So, according to that source, out of state coal consumption can range from 5% to 50%. It doesn't say exactly when the 50% figure was hit, or why.