When you build Drive uploads on a service account, plan around the hard 15GB quota; it cant be increased. For larger volumes, upload into a shared drive owned by the organization or impersonate a licensed user via domain-wide delegation. Monitor quota usage so the failure doesnt arrive as a surprise in production.

Context: Stack Overflow #40535355 (accepted answer, 12 votes): uploading via the Drive API with a service account eventually fails with 'storage quota exceeded'. The accepted answer: service accounts get a fixed 15GB quota with no way to buy more. The workaround is uploading into a shared drive or using domain-wide delegation to act as a real user.