The internet eats up less energy than you might think

The surge in digital activity spurred by the COVID-19 pandemic, the scientists said, has fueled the debate and prompted dire warnings of environmental damage. They are concerned that wayward claims, often amplified by social media, could shape behavior and policy.

Exaggerated claims, the pair said, are often well-intentioned efforts by researchers who make what may seem like reasonable assumptions. But they are not familiar with fast-changing computer technology — processing, memory, storage and networks. In making predictions, they tend to underestimate the pace of energy-saving innovation and how the systems work.

The impact of video streaming on network energy consumption is an example. Once a network is up and running, the amount of power it uses is much the same whether large amounts of data are flowing or very little. And steady improvements in technology decrease electricity consumption.

In their analysis, the two authors cite information from two large international network operators, Telefónica and Cogent, which have reported data traffic and energy use for the COVID year of 2020. Telefónica handled a 45% jump in data through its network with no increase in energy use. Cogent’s electricity use fell 21% even as data traffic increased 38%.

“Yes, we’re using a lot more data services and putting a lot more data through networks,” Koomey said. “But we’re also getting a lot more efficient very quickly.”

Another pitfall, the authors say, is to look at one high-growth sector of the tech industry and assume both that electricity use is increasing proportionally and that it is representative of the industry as a whole.

Computer data centers are a case study. The biggest data centers, from which consumers and workers tap services and software over the internet, do consume huge amounts of electricity. These so-called cloud data centers are operated by companies including Alibaba, Amazon, Apple, Facebook, Google and Microsoft.

From 2010 to 2018, the data workloads hosted by the cloud data centers increased 2,600% and energy consumption increased 500%. But energy consumption for all data centers rose less than 10%.

The complexity, dynamism and unpredictability of technology development and markets, the authors say, make projecting out more than two or three years suspect. They critiqued a Bitcoin energy paper that projected out decades, based on what they said were old data and simplified assumptions — an approach Masanet called “extrapolate to Doomsday.”

But Bitcoin, the scientists say, is something different — and a worry. The efficiency trends elsewhere in tech are blunted because Bitcoin’s specialized software churns through ever more computing cycles as more people try to create, buy and sell digital currency.

“It’s a hot spot that needs to be watched very closely and could be a problem,” Masanet said.

Much is unknown about cryptocurrency mining and its energy consumption. It uses specialized software and hardware, and secrecy surrounds the big centers of crypto mining in China, Russia and other countries.

So estimates of Bitcoin’s energy footprint vary widely. Researchers at Cambridge University estimate that Bitcoin mining accounts for 0.4% of worldwide electricity consumption.

That may not appear to be much. But all of the world’s data centers — excluding ones for Bitcoin mining — consume an estimated 1% of its electricity.

“I think that’s a pretty good, high-value use of that 1%,” Koomey said. “I’m not sure the same is true for Bitcoin’s share.”