I've been keeping an eye on these developments in regards to the safe harbour provisions and law.
Here's a short summary of Ireland's Data Protection laws: https://www.dataprotection.ie/docs/Transfers-Abroad/37.htm
If you scroll down to the "Transferring Personal Data to Non-Approved Third Countries" section you can see there are multiple additional methods for storing data.
Also as a few people have said in several articles this is basically a negotiating tacit to attempt to implement stronger data protection for EU citizens when being stored over seas. It would not surprise me at all if an updated version of the EU-US Safe Harbor provisions would be enacted and cover all of this, primarily without anyone really having to change a thing.
The US and in general the World is quite large and will be difficult for the EU to fully shut them out or block any data storage so they will have to come up with something relatively easy and honestly are just trying to bring the US government to the negotiating table because of how the NSA had unfettered access to information on EU citizens via Facebook and other large companies.