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sexy_wash_bucket t1_j1kv38x wrote

Oh baby I got this. Energy lawyer here. This is caused by two different situations.

First is capacity issues. PJM electricity is sold on the “day-ahead” market, meaning that one day in advance, providers “bid” on prices for dispatch, and each bidder is dispatched in reverse order from least expensive to most expensive. But if the day-ahead market bids can’t accommodate the needed estimated capacity, PJM knows there could be outages.

The second issue is the actual transmission lines. Transmission lines have a “thermal constraint”: a maximum amount of power that can flow through without the current going haywire and electrocuting squirrels. On busy electricity days, more and more electricity demand through those lines gets them very close to their thermal limits, so utilities have to cut back or risk frying their lines. In a big city like Philly, constraints can be met much faster.

But (you say), shouldn’t they have backstops in place to prevent these issues? This seems foreseeable, no? Oh yeah. When one or both of these issues presents itself, PJM has to resort to “demand response” tactics: ways to change demand so it can be closer to actual supply. The most common demand response strategy is interrupted service. The gist there is that your contract with the utility allows the utility to shut off your power for a pre-allotted amount of time and rebate you for the time without power. Another is rolling blackouts, which will certainly not be employed in this situation because I wouldn’t think people want their homes to be 30 degrees with no warning. If interrupted service users can’t even account for the overblown demand, PJM’s got big problems.

This text shows just how much energy is pumping through our grid right now (and how worried PJM is about outages and blackouts).


farmstink t1_j1ly5mt wrote

Thank you for sharing this insight, sexy_wash_bucket


tardisintheparty t1_j1m1cme wrote

I just took my energy law final three days ago. This is triggering lol one of my short answers was about the day-ahead market and the other was about transmission constraints and demand response!


YogiNurse t1_j1nogj2 wrote

Energy law seems so….specific


tardisintheparty t1_j1q8az7 wrote

Very, VERY specific. super niche. took it cause i heard it was an easy A (it was not lol)


fergy80 t1_j1lbgo5 wrote

For the first issue, couldn't they have seen this coming and purchased more power? If I'm understanding correctly, it seems like they screwed up even though they knew the storm was coming. And now they're asking us to make sacrifices for their lack of planning.


sexy_wash_bucket t1_j1lbnui wrote

Sort of. The day-ahead market is heavily regulated on a federal level by FEEC, so every provider is required to bid in the market for all of their capacity. PJM can’t do anything to increase bids besides wait for a new plant to be built. But they can anticipate when bids won’t cover projected capacity demand.

Although (into the nitty gritty here), there’s also smaller scale one-state plants that actually fall outside of FERC jurisdiction that can add to capacity, but PJM has less control over them and PJM also factors them into capacity projections.


funkyted t1_j1lmj0w wrote

PJM has the most robust capacity market in the country. It’s concerning for the future that this weekend is a problem.


felldestroyed t1_j1lzzbi wrote

So the press release this morning was citing the power plants (which I assume are natural gas) not being able to run. How would this factor into what you're saying? Is it something like what happened in Texas with natural gas plants not be winterized enough to take days of negative temps?


sexy_wash_bucket t1_j1md45k wrote

Yup. Power plants can run into a lot of issues when it’s too cold. PJM’s are much more resilient than Texas’s, but that is a very low bar. If NG plants aren’t running, electricity needs to be dispatched instead for heating purposes instead of NG. That adds to capacity needs, which makes it even harder for PJM to meet demand.


fritolazee t1_j1mnk24 wrote

Thanks for dropping knowledge! What does an energy lawyer do on a daily basis?


flyingasshat t1_j1ngl5d wrote

That a 1000 MW generating station in NJ went offline


AbsentEmpire t1_j1ma51i wrote

Well considering how cold it is outside I'm sure the thermal line limit isn't the issue.


sexy_wash_bucket t1_j1me0xh wrote

Colder ambient temperatures increase resistance in transmission lines, so it has somewhat of an equalizing effect.


blodreina_kumWonkru t1_j1mi4ib wrote

This is super interesting but weird. I get the 2nd issue, but I can't wrap my head around the 1st. Why do providers bid on electricity? We really treat power the same way do anything else that's bought/sold/re-sold? I feel silly asking this question, but for some reason that just seems bonkers to me that this would be the case to the point where providers could "run out" of energy to provide to people.


sexy_wash_bucket t1_j1mmgru wrote

Lots of boring judicial history there but the main gist is that we (the U.S.) created RTOs (like PJM) to ensure that every bit of electricity in a region was being managed by one overall regulator to maximize synergies. Every provider is required to bid (basically) 100% of their capacity on the day-ahead market, every day. If we didn’t force energy bids like this, providers could e.g. withhold energy until peak demand times to maximize profits, essentially giving an F U to people at non peak times and leaving them susceptible to blackouts. The bidding system is just the method that FERC employs to find a fair price to pay providers despite there being so many - but in reality, it’s just the chosen strategy to ensure all electricity being produced enters the market.