Is watching Netflix bad for the environment? Scientists take a deeper look at data centers

If you’re concerned about climate change, should you feel guilty about hanging out online? Maybe not.

It’s been widely reported that data centers, the nondescript buildings that house the servers that keep our phones and computers buzzing with cool stuff, could gobble up enormous amounts of electricity over the coming decade. 

But you don’t need to put down your smartphone just yet. A study released Friday in the journal Science finds that though data center demand has grown 550% in the last eight years, the energy needed to power those data centers only grew 6%.

The report gives the most definitive number for global data center energy consumption available, said George Kamiya, emerging technologies analyst at the International Energy Agency in Paris.

"Every few months it seems there’s another claim about the carbon intensity of Google searching or video streaming and often they’re outdated and ignore the rapidly changing technology that runs the internet," said Eric Masanet, the paper’s lead author and a professor of engineering at Northwestern University in Evanston, Illinois.

The researchers only looked at energy used to power the movement and storage of information online, not the electricity needed to power the phones, tablets and computers we consume that data on. 

Masanet and his colleagues did a similar comprehensive analysis of data center efficiency trends in the United States that was published in 2018. The Science paper expands the analysis to the global level. 

Masanet, who specializes in energy modeling, said data centers have seen 20% energy improvement per year, an efficiency gain that no other industry has even come close to.

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Much of those gains have come from the move to more efficient servers and other IT equipment and the global shift to both hyperscale data center and cloud computing.

It might seem that an enormous server farm would take up more energy than small local ones, but it’s actually not the case because they're so much more efficient than the traditional server rooms many companies stuck in a closet.

Today, the best estimates are that data centers represent about 1% of global electricity use. That’s the equivalent of about 200 terawatt-hours, the annual electricity use of 20 million U.S. homes, said Masanet. 

“It’s not insignificant but we don’t need to hit the panic button just now,” he said.

A tsunami of data use coming

As use of the internet has grown, concerns about how much electricity it’s using have grown with it. A large study published in 2011 found data centers probably used about 1.3% of the world’s electricity between 2005 and 2010.

Many studies since then were more simplistic and less authoritative, tending to overestimate future energy use. One claimed that information and telecommunications technology could use 20% of all electricity by 2025, said Kamiya. 

“The media has been more than happy to cherry-pick the ‘worse-case’ scenarios of these studies,” he said.

The Science paper, "Recalibrating global data center energy-use estimates" is meant to provide solid, replicable estimates that have been vetted by industry experts. 

“It’s important we start from the best available information,” because key decisions around climate and energy have to start with facts and data, Kamiya said.

Demand is ever-growing, especially given the expected growth of ultra-fast 5G networks, self-driving cars, Bitcoin, quantum computing and artificial intelligence. 

Despite that, the researchers estimate there should be sufficient energy efficiency gains still to be made in data center technology to absorb the next expected doubling of computer usage as more people globally come online and do more things.

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What comes after that is an open question. For example, no one knows how much energy quantum computing — expected to be the next computer revolution — will use.

To make sure computers don’t become energy hogs, several things need to happen, Masanet said. 

Industry and governments need to continue to encourage energy efficiency in storage and networking devices and support research on future improvements. Nations also need to collect and be open about how much energy their data centers use, particularly in Asia where data center energy is poised to grow but little reliable information is available, Masanet said.  

One welcome trend has been the move among large data companies to source their electricity from renewable energy. 

Google and Apple both purchased or generated enough renewable electricity to match 100% of their data center energy consumption in 2018. Facebook says it will reach 100% this year. 

Microsoft’s data centers ran on 60% renewable energy in 2019 and the company is aiming for 70% in 2023. Amazon hit 50% in 2018 and says it will reach 80% by 2024.

“It’s not that we can be complacent,” said Masanet. “But we don’t have to feel guilty about watching Netflix or staying connected.”

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