Guides
Data center guides
Straight answers to the questions people ask about data centers, built from government, national-lab and court sources, with every figure cited.
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What are data centers, and what do they do?
What data centers are, what they actually do, the main types from enterprise to hyperscale and AI, what they look like and why we need them, in plain English with a source for every figure.
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Why are so many data centers being built?
AI, cloud demand, big-tech spending, tax incentives and federal policy: the documented reasons behind the U.S. data center construction boom, with sources for every figure.
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How many data centers are in the U.S.?
What official and industry sources actually say about the number of U.S. data centers, hyperscale facilities and AI data centers, why the counts differ, and what the Census tracks.
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How much electricity do data centers use?
U.S. data centers used 4.4% of the nation’s electricity in 2023 and 4.7% in 2024. Official figures, forecasts to 2030, what a single AI campus draws, and grid operator outlooks, with sources.
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Are data centers bad for the environment?
Emissions, backup diesel generators, gas turbines, land and water: the documented environmental impacts of data centers, the efficiency gains and company pledges, and where evidence is contested.
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Are data centers loud?
Where data center noise comes from, why the low-frequency hum bothers neighbors, the decibel limits localities have adopted, and what the evidence says, with sources.
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How much does it cost to build a data center?
What a data center costs to build per megawatt, what drives the price, and what announced U.S. projects say they will spend, with sources.
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How long does it take to build a data center?
One data center building takes about 12 to 18 months to build. Dated timelines from real U.S. projects show how long whole campuses take.
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How big are data centers?
How big a data center is in square feet and acres, compared with football fields and Central Park, with the site sizes real U.S. projects publish.
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Data center pros and cons for a community
What communities gain and give up when a data center arrives: tax revenue, electricity bills, jobs, land, noise and water, with each figure sourced to auditors, regulators and official budgets.
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Data center cooling: how are data centers cooled?
How data center cooling works: air cooling, chillers and cooling towers, free cooling, direct-to-chip liquid and immersion cooling, what closed-loop really means, and the water-versus-energy trade-off, with the cooling every tracked project reports.
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Are data centers bad for your health?
What the evidence says about data centers and health: backup generator and turbine emissions, noise, electromagnetic fields from power lines, and battery fires, with government and peer-reviewed sources.
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Data Center Alley: how Ashburn became the world’s data center capital
Why Loudoun County, Virginia is called Data Center Alley: the 1992 internet exchange, by-right zoning, 233 buildings, $1.2 billion in tax revenue, grid strain and the 2025-26 rule changes, with sources.
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Lake Tahoe’s power supply and the Nevada data center question
Why NV Energy is ending its power supply to Liberty Utilities’ 49,000 Lake Tahoe customers, what NV Energy says about data centers, and what the CPUC and Nevada IRP filings actually show.
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What is an AI data center?
What makes a data center an AI data center: GPU servers, far denser racks, liquid cooling and campuses measured in hundreds of megawatts, with real U.S. examples and sources.
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How do data centers make money?
The business models behind data centers: leasing space and power, selling cloud computing and renting out AI chips, with the latest figures from the companies that run them.
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Erin Brockovich’s data center map, and how it compares
What Erin Brockovich’s data center map shows, where its data comes from, and how it compares with Compute Atlas, Epoch AI, Data Center Map, Cleanview and the Census.
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Why are data centers bad?
The main criticisms of data centers, from power bills and water to noise, air pollution, land and tax breaks; what the evidence shows for each, what supporters say, and how public opinion has shifted in 2026.
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When was the first data center built?
The history of data centers, from ENIAC’s 1946 computer room through mainframes, the internet exchanges of the 1990s and the cloud to today’s AI campuses, with a primary source for every date.
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What is PUE (power usage effectiveness)?
PUE, or power usage effectiveness, measures how much of a data center’s electricity reaches its computers. The formula, what counts as a good PUE, how averages have changed, and what the number leaves out.
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Data center tiers: Tier I to Tier IV explained
What Uptime Institute’s Tier I, II, III and IV ratings mean, how Tier 3 and Tier 4 data centers differ, how certification works, and why the “Tier 4 generators” in local filings are something else entirely.
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What is behind-the-meter power?
Behind-the-meter power is electricity a data center makes for itself instead of drawing it from the grid. How it works, why developers want it, the air and grid trade-offs, and the rules regulators are writing, with every tracked example.
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What is a colocation data center?
A colocation data center is owned by one company and rents space, equipment and services to others. How colocation works, how it differs from enterprise, cloud and hyperscale data centers, and how tight the market is in 2026.
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Data center technician: what the job is, what it pays and how to get one
What a data center technician does, what the job pays compared with federal wage data, the shifts, the certifications employers look for, and the training programs Microsoft and AWS run with community colleges.
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What is a neocloud?
A neocloud is a cloud company built around renting GPUs for AI, such as CoreWeave, Nebius and Crusoe. How neoclouds differ from AWS, Azure and Google Cloud, who their customers are, where their data centers come from, and the risks analysts flag.
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Home data centers: what they are, who’s building them and what hosts get
What a home data center is in 2026: SPAN’s XFRA nodes, built with Nvidia GPUs and installed at homes that SPAN says get cheaper power and internet; Heata’s water-heating servers; how Nvidia’s PAIR home AI cluster differs; who can sign up; and the open questions researchers, analysts and reporters raise.
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How much water does AI use?
Google and OpenAI put one chatbot prompt at about 0.3 mL of water. Why other estimates run higher, and what a data center near you may draw.
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Data center construction: what’s being built, and how
Live count of U.S. data centers under construction, how a campus gets built, who builds it, and how long and how much it takes.
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What is a hyperscaler?
A hyperscaler runs data centers at global scale for cloud, search, social media or AI. Who counts, what they spend, where they build in the U.S.
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Why do data centers use so much water?
Why data centers use so much water, and how much: U.S. data centers directly used about 17 billion gallons in 2023 and far more indirectly through power plants. How cooling uses water, whether data centers recycle it, and published figures project by project.
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Data center jobs: pay, where they are, and how many are created
Jobs by state, technician and trade pay from federal wage data, and every jobs promise in the Census.
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The largest data center projects in the U.S.
Tracked projects ranked by published capacity, investment and site size.
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Local data center rules tracker
Noise limits, setbacks, moratoriums and state laws that apply specifically to data centers.
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Data center glossary
Sourced definitions of the terms used in filings, hearings and utility cases, from PUE to PILOT.
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Data center moratorium tracker
Every local and state pause we can source, with dates, lengths and scope.
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