By choosing Antwerp or Rotterdam they don't have to pump any money anywhere SH. By handing out grants they are simply reacting to decisions made elsewhere. It also makes environmental sense because bigger ships (and therefore fewer) can be used - both Antwerp and Rotterdam can take ships of up to 16 metres draught and 15,000 TEU + capacity, currently only Le Havre can manage these.
The trade from Ireland is likely to small relatively small regular amounts not requiring large vessels. This rather smacks at being a political decision.
