WTF are data centers, and why is everyone fighting about them?

Data centers are making headlines, but the unremarkable facades of these facilities offer little hint of the powerful technology housed inside.

As the demand for AI grows, the data centers that power our digital world are needed to process the massive quantity of information required for the tech. Yet, these facilities are often criticized for their energy use and environmental impacts. 

A better understanding of this infrastructure is key to understanding what future developments could mean for your community. Keep reading for a crash course on what data centers actually are, how they’re tied to AI and why they’re raising environmental concerns. 

What is a data center? 

A data center is a physical space — a room, building or multi-building facility — that houses IT infrastructure. Mainly, these sites store large collections of servers, or computers that are designed to store and process data. 

There are an estimated 5,426 data centers in the US as of March 2025, according to Statista. This far outpaces other leading countries, like Germany, the UK and China, which only have a few hundred. The US has become a hot spot for data centers. The prevalence of top tech companies that rely on the facilities for AI processing, regional advantages and tax incentives all play a role in boosting their presence.

Virginia has long been home to the country’s largest cluster, known as “Data Center Alley,” but they exist all over the country. In the greater Pittsburgh area, for example, there are 35 data centers, according to the market research group Data Center Map, which offers a region-by-region count.

However, since there are no regulatory requirements to register the facilities in any sort of central database, this map is just an estimate. 

Why do data centers exist? 

In the information age, data production and storage are the building blocks of the digital world. 

Every day, people send large files through Gmail, post on Facebook, shop on Amazon, download movies from Netflix and do countless other things that generate data. All that information has to go somewhere, and that place is what we call “the cloud.”

But despite the name, the cloud isn’t a faraway place in the sky. When someone stores data “in the cloud,” it’s still saved on physical disk drives, just not on your personal device. Instead, it’s housed in servers located in data centers.

In fact, “the cloud” is often just shorthand for the core service that data centers provide: storing, processing and delivering data at scale.

In 2024, the world generated, captured, copied and consumed an estimated 149 zettabytes of data, according to Statista. For reference, data storage is measured in bytes. While it can vary, a single character, like the letter Y, takes one byte to store. A zettabyte is 1,000,000,000,000,000,000,000 bytes.

How are data centers connected to AI? 

Data centers have existed for 80 years, but the public’s interest in them has increased dramatically with the rising popularity of artificial intelligence. 

AI-focused companies require a massive amount of data to train their machine learning models. These models also require significant computational power to produce valuable outputs. As AI tools become more widely adopted, the demand for data centers also increases because all of the data needed to run AI programs needs to be processed somewhere.

That’s why graphics processing units (GPUs) have become so important in recent years. The technology can simultaneously perform the multiple complex computations needed to train and run machine learning models. These GPUs are inside the servers that are housed in data centers. In other words, GPUs serve as the backbone to make all this data processing more efficient.

How much power do data centers use? 

Data centers run 24/7, and along with powering servers, there are backup generators and cooling systems that need power, too. 

Data centers consume about 4% of the nation’s electricity, according to a 2024 report by the US Department of Energy. By 2028, that’s expected to jump to about 7% to 12%, which would equate to between 325 and 580 TWh (terawatt-hours) of annual energy usage. 

How much energy is that? By one estimate, 1 TWh would power the world’s data centers for 15 days, or power the state of California for slightly less time, about a week and a half. Data centers used about 176 terawatt-hours of energy in 2023, according to federal statistics. That’s enough to power 16 million homes for a year.

OpenAI’s Sam Altman has said an average ChatGPT query uses about a third of a single watt-hour, or “about what an oven would use in a little over one second, or a high-efficiency lightbulb would use in a couple of minutes.” 

How has energy usage changed over time?

Data centers use a lot of energy, but traditionally, they haven’t done so very efficiently.  

An investigation over a decade ago found that data centers only used about 6% to 12% of the electricity powering their servers to actually perform computations. The rest of the power was mostly used to keep servers ready for a surge in activity that would slow down or crash operations. 

A more recent study found that Microsoft’s data centers reached over 60% server utilization rate, meaning energy was used more efficiently. Other major companies like Amazon have claimed their data centers are becoming more energy efficient, but it’s still hard to say how energy efficient data centers are today. 

What are the environmental impacts of data centers? 

Like any other type of facility, a data center’s environmental impact will somewhat depend on the type of energy it uses. Some of the facilities are powered by clean energy, like wind or solar, but others aren’t. 

Data centers in some regions have been cited for violating clean air regulations and have been identified as top stationary diesel polluters. Since data centers are hypervigilant to prevent power failures and potential crashes, these facilities often use banks of generators that emit diesel exhaust and nitrogen dioxide. 

Some major tech companies are actually getting farther away from their climate goals because of how much fossil fuel energy data centers use. Google’s carbon emissions rose 48% and Microsoft’s rose 30% because of data center power consumption. 

In response to the projected demand for data centers, utility companies are planning at least 10.8 gigawatts of gas-fired power plants and could delay the closures of at least 9.1 gigawatts of fossil-fuel power plants, according to a recent analysis by the nonprofit research firm Frontier Group. 

What does this all mean for a natural resource like water?

There is also an environmental concern around the amount of water data centers use. 

Data centers generate a lot of heat from the amount of electricity they require, so they utilize water-based cooling systems to keep servers operating. 

A single data center can use up to five million gallons of drinking water — or enough water to fill 7.5 Olympic swimming pools — per day, according to a report by Bloomberg. That drinking water is often treated with chemicals, so either it evaporates in the cooling process or it’s rendered unsuitable for drinking or farming use. This means the large amount of water used by data centers is effectively removed from the local water cycle. 

On a global scale, data centers, driven by AI demand, are projected to use 4.2 to 6.6 billion cubic meters of water per year by 2027. For reference, the whole country of Denmark uses that amount of water each year. 

This comes at a time when climate change is driving freshwater scarcity across the globe. And the problem is exacerbated by the fact that data centers operate best in dry climates, meaning these facilities are often placed in water-stressed regions. 

What’s it like to live near a data center?

Data centers do drive substantial economic growth in the US. 

Employment at US data centers grew more than 60% from 2016 to 2023, totalling over 500,000 jobs, according to the US Census Bureau and the Bureau of Labor Statistics. With the indirect positions created from new data centers, that job total is estimated to be closer to 4.7 million. 

While more jobs may be created in regions where the centers are built, it can be unpleasant to live near these facilities.

Nearby residents have complained that data centers produce a constant leaf-blower-like sound. Some say they’ve had medical complications because of the constant noise. 

Others have claimed that nearby data centers have caused constant low water pressure in their homes and emit light pollution. 

Also, energy costs can be higher in these areas. Utility companies have been found to pass on some of the costs of powering these facilities to nearby utility customers. 

Residents often learn about these things after it’s too late, as big tech companies have pushed for developers of these projects and local leaders to sign non-disclosure agreements to keep details of future data centers under wraps.  

In exchange for some of the reported downsides, data centers say they offer community benefits, too. Jobs, infrastructure development, tax revenue and boosting the business ecosystem are all cited as potential gains.

➡️ Read more:

• Inside Data Center Alley’s sweltering Virginia summer, where cooling costs energy
• Amazon to make massive $20B+ investment in Pennsylvania AI jobs — with data centers in tow
• Data center leaders sound the alarm on energy concerns — and a better public narrative