Hey there,

I am the tech team lead at Mobility House (the company behind taking the batteries and doing the real time control in that setup) for that particular project. https://www.mobilityhouse.com/int_en/magazine/press-releases...

It's actually a really cool setup that allows us to take in excess solar (that isn't used onsite) to charge the batteries, the batteries actually act as backup power for the event days (that AFC Ajax plays). When not needed they provide frequency containment (grid stabilization to prevent brownouts+blackouts) for the European electrical grid at large (on days where it is financially viable to do so).

If you have any questions I would be more than happy to discuss more :)