The system in the article works alongside gas and wood chips heating, so there are other options in place if the sand battery cannot be "charged".
FTA:
> The project will cut fossil-based emissions in the Vääksy district heating network by around 60% each year, by reducing natural gas use bu 80% and also decreasing wood chip consumption.
Not really, we're currently borderline. If OL3 goes down, and it's simultaneously cold over the nordics + northern germany and the baltics, and no wind, our industry will have to shutdown.
FTA:
> The project will cut fossil-based emissions in the Vääksy district heating network by around 60% each year, by reducing natural gas use bu 80% and also decreasing wood chip consumption.