Water, water, everywhere and not a drop to drink. Humans need freshwater and getting enough of it is an ever-present challenge. 

Yet the earth is covered in water! Over half of the planet is ocean! The problem of course is that you cannot drink it because it is too salty. 

Desalination is the process of removing salts from salty sea and brackish water to produce freshwater. The goal is simple, but the technologies are complicated and energy intensive. And we often power these processes with oil. 

Ideally, we do not want to burn any more fossil fuels to get this water. And that is why people sometimes want to use nuclear energy to power the whole process.