Hydro Energy

By far the largest source of renewable energy, hydro-electric power produces about 15% of the world's electricity, compared with 3% for other renewables, with still lots of room for growth. New Energy Finance, a research firm, reckons that less than one-third of the world's potential capacity has been developed.

Thousands of data centers, filled with thousands of powerful computers, consume lots and lots of energy, rivaling aluminum smelters in the energy they consume. Often just as much power is needed for cooling them as for computing. Building them close to a dam solves both issues in an optimal way.

Advantages

Energy can be produced reliably and constantly.
Can also store energy (by pumping water back up) to meet peaks in demand.

Drawbacks

Dams are expensive to build
Dams can impact dramatically human settlements, historical sites and fishes
Dams deteriorate, and if they break it can have a devastating impact downstream.