Lot of industry, especialy heavy industry, chemical plants are running 24/7.
For expensive night prices see electricity prices in Europe, expensive natural gas, coal power production with carbom tax.
https://app.electricitymaps.com/map/zone/DE/live/fifteen_min...
Right...so they also run during the day (that's what 24/7 means), when everyone else is using electricity. At night they're the only users. Which means less demand at night compared to the day.
> see electricity prices in Europe
This article is about Pennsylvania. That isn't in Europe.
You are right, PJM grid is coal, nuclear and gas dominated.
https://app.electricitymaps.com/map/zone/US-MIDA-PJM/live/fi...