Your project exceeded quota for free storage for projects : we've started to get an error while querying 

error={"location":"free.stor
age","message":"Quota exceeded: Your project exceeded quota for free storage for projects. For more information, see https://cloud.google.com/bigquery/troubleshooting-errors","reason":"quotaExceeded"})

But I can't find any info about "quota fo free storage"

What exactly the quota is about?
