Guide to a Greener Data Center

Data centers are responsible for about 2% of global energy consumption each year, which is roughly the same as the airline industry.  Fortunately, there are many ways to decrease the energy usage of data centers without breaking the bank. Below are tips on how to reduce the energy consumption of data centers and server closets.

Although data centers greatly decrease the cost of running and cooling servers, nearly 40% of servers are not stored in data centers. Taking inventory of all of your institution's servers and their locations can help ensure that your servers are stored in the most efficient location possible. If your business does not have the capital to build your own data center or retrofit a specified room for secure and efficient server storage, consider leasing space from a nearby group data center or a cloud-based data storage service.

According to a study reported by Energy Star, 15-30% of data center electricity consumption is used to power idle or unused servers. You can use an inventory of the servers in your data center to schedule regular checks on server usage and CPU consumption. Look for and consolidate servers that store repetitive information. If any of the servers are no longer used, consider using those servers to store other information.  If some servers are used rarely, host the information in a more efficient server cluster, which reduces the number of backup servers needed.  Virtualize and use more efficient cloud services when possible.  Develop a plan to continue to check in and take inventory on server usage regularly.

Energy Star certified servers run more efficiently, use less energy, and cost less on each electricity bill.  Even though a sustainable server may cost more upfront than an uncertified server, many green certification standards, such as Energy Star, require that the monthly energy savings equal or exceed the cost difference within a reasonable amount of time.

Data center design has become much more efficient in recent years due largely in part to advances in cooling technology.  The hot isolation (also known as the hot aisle/ cold aisle) layout can make data centers much more efficient.  Turn adjacent pairs of server rows towards each other so that the hot sides face each other, which prevents the the hot air from mixing with the cold air, reducing the amount of cool air needed.  You can also decrease how much the hot and cold air mixes by using flexible strip curtains and/or rigid barriers.  If you have more money to devote towards data center design, you can also retrofit your air conditioner with variable speed fan drives, install an air-side and/or water-side economizer, and/or replace your old air conditioning system with a more efficient one.  There are numerous other ways to improve the cooling efficiency of a data center, but this short list is a good place to start.

Although it is not always feasible, if a company has the capital to invest in sustainable practices such as renewable energy, it can lead to incredible savings in the long run.  In 2017, Apple's data centers required around 1106 million kWh of electricity, which, based on the average price of a kWh of energy in the U.S. ($0.12), could have cost them nearly 133 million dollars just to power their data centers.  However, 99.7% of their data centers' electricity was generated or offset by renewable sources. Apple and Google both have initiatives to redesign their production strategy to reuse as few materials as possible in their manufacturing processes.

Power Usage Effectiveness (PUE) is a common measure of data center efficiency that is calculated by dividing the total power used by a data center by the power specifically consumed by the servers.  A lower PUE means that the data center is more efficient and is using less energy to power non-computing infrastructure, such as the air conditioning. Once you know your PUE, you can estimate potential savings and use these tips to determine the most efficient way to improve it. Google used its DeepMind AI to program a neural network that developed a formula to minimize the PUE.

Newer servers can be stored at much higher temperatures. Experts now recommend keeping your data center's temperatures between 65°F and 80°F. To prevent over-cooling your data centers check the maximum temperatures at which your servers can be stored and readjust the air conditioning to match the maximum temperature. Data centers can save 4-5% in energy costs for every 1°F increase in server inlet temperature.