I think the article is misleading. The spot price is about supply and demand over an extremely short time period and has dipped below zero because at the moment

I think the article is misleading. The spot price is about supply and demand over an extremely short time period and has dipped below zero because at the moment gas storage in europe is very full, so if you've got a load of natural gas to sell no one is buying because there's nowhere to put it. This is probably related to unseasonably warm temperatures in Europe at the moment, so people are using less gas than expected to heat their homes. The high prices you pay as a homeowner are to do with high expected demand over to winter relative to the available supply, because the supply has been seriously reduced due to the war in Ukraine.