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California grid emissions go "negative".

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On a low demand Sunday - CAISO is seeing a large (2000+MW) amount of exports. This is due to excess solar which is being taken by neighboring states.  Because of this overall CO2 emissions dipped below zero.  It will be interesting to see if this turns into a trend and if it continues for longer stretches of time in the future.

Obviously these are not true negative emissions for the Western grid as a whole. They are just negative for CAISO accounting. However, the more solar from CA that neighboring states use the quicker the remaining coal plants in West will close.


Joe Deely's picture

Thank Joe for the Post!

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Bob Meinetz's picture
Bob Meinetz on Apr 22, 2019 1:57 am GMT

Joe, your Black Swan moment is duly acknowledged - but twenty minutes later, they're already positive (672 mTCO2/hr). What do you think emissions will be at 7PM, or the total for the day?

onedit: At 7PM emissions are 3,303 mTCO2/hr, will probably reach 5,000+ by 8:30 PM (emissions set an April high on Thursday: 9656 mTCO2/hr. I guess the sun went down).


Joe Deely's picture
Joe Deely on Apr 22, 2019 4:22 am GMT

Just to be clear Bob that "moment" lasted for 65 minutes from 1:55pm till 3pm.  Emissions were "negative" for all those times slots. Average for that hour was -45 mTCO2/hr.

Total for yesterday was about 70,000 mTCO2. I'm guessing it will be less than 60,000 mTCO2 today.

My question is - why is NG generation still above 1,000 MW when exports are greater than 2,000MW? - see below.

Why can't CAISO get NG generation closer to zero? Contracts for those NG plants? or are they scared to go lower?

I want to see NG near zero and imports below zero. May have to wait for more storage on CAISO before we see that.

Bob Meinetz's picture
Bob Meinetz on Apr 22, 2019 4:16 am GMT

Joe - can't see your image if you uploaded one (?)

I don't know why NG generation isn't closer to zero. A hypothesis would be: hour-ahead contracts had a safety margin built-in to both ensure sufficient electricity for the CAISO grid, and account for variability.

I agree - more storage would help compensate for last-minute variability, and avoid importing some electricity. But with 30% of CA electricity coming from out-of-state, including most hydro, generating all electricity in-state probably isn't the cleanest or most cost-effective option either.

Matt Chester's picture
Matt Chester on Apr 22, 2019 9:24 am GMT

Obviously this is just a start, as you note, but I do believe these instances will start becoming more common. Signs of things to come, perhaps?

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