“Spanish consultancy AleaSoft Energy Forecasting recorded negative hourly electricity prices for all but one European energy market it analyzed during the first week of April, including in the Spanish and Portuguese markets for the first time. It also registered an all-time production record for photovoltaic energy in Portugal and the second highest value ever recorded in Italy”
The article you mentioned specifically mentions inland evaporative pool to turn those brine for road salts or other uses. But the problem is just that no one is doing it.