We recently heard how  European data center energy is not growing as fast as has been feared. Now we have encouraging news from the US. A report from the Lawrence Berkeley National Laboratory has found that growth in US data center energy is slowing right down.

In the whole of the four-year period up till 2014, the energy used by US data centers only grew by a total of four percent - that‘s one percent per year - according to the report, United States Data Center Energy Usage, which was put together by researchers at LBNL led by Arman Shehabi, along with Jonathan Koomey from Stanford, funded by the Federal Energy Management Program of the Department of Energy.

Projected total US data center energy usage
Projected total US data center energy usage – Lawrence Berkeley National Laboratory

Well, that’s a surprise!

To give the context, this will be a surprise to people who have extrapolated from earlier reports - in particular a report that came out in 2011, headed by Koomey, which estimated that around two percent of the electricity produced in the US was consumed by data centers.

Data centers have been growing exponentially since then, because that’s when services like Youtube and Facebook really tarted to take off, along with the corporate cloud. So people have argued that the energy used by data centers must also be exploding. Back-of-envelope calculations have suggested that we can’t generate enough power for the data centers used in future years.

It turns out the situation is much less dramatic - and Koomey’s 2011 report should have given the clue. This found that the rate of increase of power usage by data centers was slowing, and that process is confirmed in this report.

In the first five years of this century, up till 2005, the energy used by US data centers expanded by 90 percent. In the next five years up till 2010, that slowed down, only putting on a further 26 percent growth.

Combine the possibilities, and data center energy usage in the US could actually go down by 45 percent by 2020

Now, it seems the growth rate has slowed still further, even though the number of data centers has grown. The number of servers has been growing more slowly, as organizations virtualize and consolidate, and buy more powerful machines. The power demands of each server have dropped.

That, and the recession, ushered in a lower growth in power usage through the whole of the 2010s, according to the new report - even despite a huge growth in data consumed.

Now, this could continue for the rest of the decade, but the new report introduces some possible variations that change things again.

Just to show the way in which increased efficiency is helping, the report includes a projection of energy use if efficiency remained at 2010 levels. That would require a total of 600 billion extra kWh across the decade. But of course we are becoming more efficient, so that’s not going to happe.

There is more to be done

More interestingly, the report notes that there is is still a lot more to done. Not everyone is making best use of management technologies, and not every one applies best practices. If they were more widely used, power usage could actually go down.

And then there’s the “hyperscale shift” where the cloud aggressively replaces enterprise data centers.

Combine these possibilities, and data center energy usage in the US could actually go down by 33 billion kWh per year by 2020, which the authors say is a saving of 45 percent compared with current efficiency trends.

There’s lots more detail in the body of the report, but for now, the headline is enough to give us pause - and it’s a good data point to have ready next time you hear apocalyptic predictions about data center energy usage.

At DCD Webscale in San Jose 19-20 July, Arman Shehabit of LBNL will be delivering a keynote on this report, followed by a discussion on data center energy use

A version of this article appeared on Green Data Centere News