yes but some of this 2% require massive amount of potable wáter as cooling and this (zero-carbon initiative) only account of direct electricity use not indirect use
yes you need ,sorry for being late too the the part, you don't use salt water and contaminated water source because they damage the machine faster , the only example in function was a showcase from Microsoft few years back when the put few servers running, but it was most expensive than consume the clean water from the same source we do so mostly a stunt, maybe a preview.
You don’t, but I’m assuming that many companies which either sell or does water cooling may still use municipal treated water because doing it differently requires quite a lot of corporation.
What we try to do here in Denmark, which is a small country and why we do this, is that we try to use the water cooling for both cooling and heating. I’m not completely sure if the correct English term is district heating, but it’s where you cook the data centres with water that is then cooled down in a long circuit where it’s used to heat nearby homes. It’s basically what we do with excess heat from fossil fuel plants and garbage burners as well (we also use the heat to generate electricity in some cities). I believe some of the data centres build by companies like Facebook and Microsoft are working on this with the local cities, but it’s mainly done because of regulation and political demands and not so much because the companies themselves want to do it by default.