In a large data center, operational expenses (such as power bills) can often be enormous and even a greater burden than the initial cost of building the data center and buying the physical equipment itself. To reduce expenses therefore, companies will strive to reduce both the energy consumption of the physical server equipment itself as well as the consumption of energy required to house and cool this equipment.
Traditional cooling infrastructure such as air conditioning systems use a lot of energy. Therefore companies are looking to reduce the PUE of their data centers in many different ways – such as using closed loop liquid cooling systems (instead of fan cooling) on the servers themselves, which are more efficient at cooling the server and therefore allow the servers to be operated at higher ambient temperatures (requiring less or no additional air conditioning), or even using liquid immersion cooling where the entire server rack is immersed in a non-conductive fluid for cooling.
Other companies can reduce their PUE by locating their data center in a colder climate – such as northern Europe, Russia or Alaska, requiring less additional energy to reach a lower ambient temperature, and Microsoft is even experimenting with locating data centers under the ocean.