It's funny how capitalist apologists in this thread attack the format of a tweet and people not reading the actual article, when they clearly haven't read the original article.
Negative prices are only mentioned in passing, as a very rare phenomenon, while most of it is dedicated to value deflation of energy (mentioned 4 times), aka private sector investors not earning enough profits to justify expanding the grid. Basically a cautionary tale of leaving such a critical component of society up to a privatized market.