This is a great threory. Though the claims of reducing emissions are true, there are still considerations to be made in changes that will be experienced to the environment which have the potential to be an even more direct and damaging impact.
One consideration will be the effect of the local currents with in that area. Depending on the changes in temperature and the eifficency of this unit, it could greatly affect the local currents having a massive effect on the local marine environment.
I understand, this may be a little extreme, but I feel it must be discussed and considered.