All the Zooming, Slacking and online shopping that people are doing during the pandemic is having a big impact on the Northern Virginia suburbs.

That’s because a significant percentage of the world’s internet traffic runs through roughly 70 data centers based in Loudoun County, Virginia — and 2020 was a boom year for, well, everything internet.

According to commercial real estate firm JLL, companies snapped up more than 320 megawatts of juice at Northern Virginia data centers in 2020, enough to power between 23 and 40 homes for an entire year. (Data center use is typically measured in energy consumption instead of square footage.) That’s more than twice the inventory users demanded in 2019, says David Barnett, who leads research in the Americas for JLL.

Most of that demand came from a handful of social media companies — Barnett declines to say which ones — though he says teleworking also played a big role.

“The pandemic served as an accelerant,” Barnett says. “Everyone had to use a computer and video streaming services that they probably didn’t use as much, if at all, before the pandemic. They needed more power just to do all that computing — and all that Internet traffic has to go through data centers.”

Hulking, high-security data centers hogged up almost 18 million square feet of real estate in Northern Virginia at the end of last year, per JLL. That’s equivalent to about 30,000 small studio apartments, or more than 7,000 single-family homes. Another 5.7 million square feet were under construction at that time, and the firm expects 11.6 million square feet to be added in future years. Google, which operates two facilities in Loudoun, recently announced a $600 million data center expansion in the county.

The enormous concentration of data centers in Ashburn, Virginia, is why the area earned the nickname “Data Center Alley.” But data center construction has started to stretch out across the state. Technology firms have been driving a push into Prince William County, southern Loudoun County and beyond, as companies like Amazon Web Services aggressively ramp up their cloud computing capacity, according to Data Center Frontier.

Virginia’s economic development officials tend to view this as fabulous news. Data centers don’t produce a lot of permanent jobs, but the jobs they do create usually pay high wages, and they can lure other tech companies to a region. Parts of Virginia devastated by job losses in coal mining, manufacturing, tobacco, and correctional facilities have started to attract data centers, bringing employment and investment to low-income rural communities, according to a 2020 report commissioned by the Northern Virginia Technology Council.

That’s one reason Virginia granted $417 million in tax breaks to data centers between 2010 and 2017.

But the data center boom worries environmentalists, who say an insatiable appetite for technology infrastructure is expanding Virginia’s dependence on dirty energy. In 2019, Virginia data centers used about as much electricity as nine large coal-powered plants can produce, according to Greenpeace. Much of that demand was from Amazon Web Services — a leading provider of cloud technology to the federal government.

“Tech giants like Amazon have made promises to power their data centers with renewable energy, but a closer look into the heart of the internet reveals their rapid growth is driving more investment in fossil fuels,” the environmental organization wrote in a 2019 report.

Dominion Energy, Virginia’s largest energy provider, says it plans to add more renewable sources to its power grid in response to new environmental legislation and pressure from technology companies seeking to reduce their reliance on fossil fuels. Google, Facebook, Apple, and Amazon Web Services have pledged to power their entire operations with renewables, though Amazon in particular is lagging behind its own goals, according to Greenpeace.

In April 2020, Virginia Gov. Ralph Northam signed legislation requiring Dominion Energy to become completely carbon-free by 2045, with most of the state’s coal-fired plants shuttered by the end of 2024.

It’s not clear how soon Northern Virginia’s data centers will be able to derive all of their energy from renewable sources, but one thing is virtually guaranteed, says David Barnett with JLL: demand for data centers isn’t going anywhere.

“We’ll have to see how the dust settles after the pandemic, in terms of remote working and hybrid working,” the researcher says. “But people using the internet less doesn’t seem likely.”

This story was updated to remove a reference to the frequently cited statistic that 70% of the world’s internet traffic flows through Loudoun County. That figure may be an overestimate.