Can someone tell me what is these data centres

They do use wind turbines, in so far as they are taking the electrify from the national grid which is in turn fed from the turbines (Electricity | Energy Statistics In Ireland | SEAI), they can't just pop a load of turbines onto the top of their buildings to generate their own heat for a number of reasons, first off being as you point out turbines are often near the coast where they don't impact anyone, take a drive past a few wind farms at some stage and imagine those being located near data centres which are normally next to urban areas. The other issue with them generating their own power is the quality of the feed, wind turbines are like dynamos on a bike, the faster you go the brighter the light and vice versa, this isn't suitable for a data centre which needs a consistent, clean power source, even the standard power supply isn't clean enough for a lot of the data centre so it'll go through a UPS first.

Outside of the actual data, the largest output from a data centre is heat, anyone using any kind of technology knows that they give off heat, now imagine thousands and thousands of servers, data centres are very smart in re-using this heat, often it is brought back into the building to keep it at a standard temperature or turned back into electricity in some kind of heat recovery system, but a lot of time the heat is just "lost", there are plans to feed this heat back to local residential buildings which in turn will reduce the need for energy from those premises but that means that the data centres need to be close to residential areas and there is a bit of a housing issue at the moment so it's not always feasible to build the data centres close to where people live.

In my opinion we're going to be in a constant power battle and as we look to move more and more things to electricity the more and more electricity we will need, for the past decade or so there has been a massive shift to electricity, most houses are being build with electrical based heating solutions, we're being pushed to electric cars, etc. etc., that power has to come from somewhere, data centres are the "low hanging fruit" at the moment but there will be more and more drains on the system as well as more and more power is needed on a 24/7 basis, the future is the house with 2 electrical cars, an electrical heating solution as well as loads of smart devices to make your life easier (any ad break shows this) but I don't know what is going to power it, for example in my house having 2 cars charged over night, 2 electrical showers in the morning as well as all the other "stuff" will mean I'll be using more power than a small factory of 20 years ago all while the cost of power goes up.

Chances are the roof of the data centre is used to get rid of a lot of heat so the whole place would need to be re-done to accommodate solar, other factors would be shading, facing south(ish), etc. etc., then the fact that we have vast periods without sun light which means the solar energy will need to be "stored" for night time use which would take up a lot of space in an already full area so it makes sense that they'll need a new location.

Again, in my opinion, the requirements for data centres are simple, companies (Facebook, Google, Apple, Microsoft, Amazon) need data centres to run their operations, for example as companies move to Office 365 this means that there's no need for companies to have their own Exchange server so they "rent" part of 1 that's located in a Microsoft data centre, in a roundabout way this will have a positive impact as a large number of servers can be turned off but all that will be seen is the power used by the Microsoft data centre, as these companies are already in Ireland it's in our interest to give them what they want, after all if they are to setup their data centres in another country what's to stop them taking a load of jobs with them?