How smart batteries create efficient data centers

The electric grid experiences the same daily peak demand issues as our freeways, seeing pronounced surges during the critical parts of the day. This makes providing power more expensive because extra power plants have to be built to meet this peak demand.

Servers that provide the world's Internet content are also their busiest during this peak power period. And with the Internet consuming two percent of the world's energy and predicted to surpass the airline industry by 2020, the problem is only getting worse.

Furthermore, companies that have large IT deployments are being challenged by rapid expansion and rising energy costs.

For companies like Akamai that host their IT infrastructure in third-party collocation data centers, energy is typically priced based on the total supplied power in kilowatts (KW) charged at a fixed rate in $/KW, for example 50KW at $200/KW per month, similar to a fixed number of minutes for a mobile phone plan. While the supplied power is fixed, the power drawn by the servers vary with server activity which peaks and lulls daily. Energy costs could be reduced if the server peak-power demand, and hence the supplied power, can be lowered.

One of the innovative ways Akamai is looking at mitigating this challenge and reducing network operational costs is to reduce the grid-based power supplied to its servers during peak demand by supplementing with batteries and recharging the batteries at night when most energy consumers are asleep and power production is cheap and plentiful.

A recently published research paper by Ramesh Sitaraman, Akamai Fellow and UMass professor, written in collaboration with researchers at Penn State and BBN, evaluates using smart batteries in an Internet-scale distributed network such as the Akamai Network. The smart batteries that are placed inside a server or within a server rack detect when a server's power draw crosses a threshold level, as it becomes busier, and then supply battery power until the server power draw drops below the threshold. The batteries would recharge at night or whenever energy and server demand are low.

Next page: Counting the energy savings