How to read this site

A plain guide to data centers, the generators they build, the state permits that govern them, and what the numbers on the map do and do not mean. Pennsylvania, Virginia, Texas, and Oregon so far.

What this site is

The map shows every data-center permit we have found in the states we track, one ring per site, with the state agency record behind each row. Air permits for backup generators and on-site power carry the figures (engines, megawatts, emission caps); stormwater, wetlands, water, and tank permits are listed by type and status from each agency's tracker. Where a cell is blank, no public document states the figure. Where a number comes from a company statement rather than a permit, the cell says so.

Each state's permits come from its own agency: Pennsylvania's Department of Environmental Protection (DEP), Virginia's Department of Environmental Quality (DEQ), the Texas Commission on Environmental Quality (TCEQ), and Oregon's DEQ. The sections below that name a state apply only there.

What a data center is

A data center is a building full of computer servers. It needs electricity around the clock to run them and to cool them, because servers turn nearly all of that electricity into heat. A large campus can draw hundreds of megawatts, which is more than many towns.

Developers are choosing Pennsylvania because it has room, water, pipelines, and a spot on the PJM grid that serves much of the eastern United States. Several proposals sit on former power-plant or industrial land that already has grid connections. In August 2026 the governor signed Executive Order 2026-05, which sets conditions on DEP review of large data centers and created a public DEP Data Center Permit Tracker. This site is built on those permits.

Why they have generators

If the grid fails, the servers must keep running, so almost every data center installs diesel backup generators, often dozens or hundreds of them. They are meant to run only during outages and for short readiness tests, and their permits cap the hours. Some projects go further and build their own power plant on site, so they do not wait for the grid at all.

The three shapes on the Pennsylvania map:

A gas plant: Homer City in Indiana County: a 4,681 MW natural-gas plant on the old coal-plant site, with 12 diesel emergency generators alongside.
Gas engines: Falls Township in Bucks County: 280 natural-gas engines proposed as primary power, plus 76 existing diesel generators.
Diesel backup only: Lancaster (176 generators) and Salem Township (109 permitted, 86 more applied for). Wyalusing in Bradford County, the third on-site plant, is eight gas turbines with one diesel fire pump, so it sits with Homer City.

Tier 4 is the strictest federal standard for new diesel engines (40 CFR Part 1039); it cuts NOx and soot far below older Tier 2 engines.
SCR (selective catalytic reduction) is an exhaust treatment that sprays ammonia or urea over a catalyst to strip out NOx.
Emergency is a legal category: an engine that runs only in outages and for testing, which federal rules limit to 100 hours a year of maintenance and readiness runs (40 CFR 60.4211).

What the permits are in Pennsylvania

Before a company builds a source of air pollution in Pennsylvania it needs a plan approval from DEP. After the equipment is built and running, DEP folds it into an operating permit. The plan approval is where the numbers on this site live: how many engines, how big, and the emission cap.

DEP announces each plan approval in the weekly Pennsylvania Bulletin, first as a notice of intent to issue, and the rule (25 Pa. Code § 127.44) gives the public 30 days from publication to comment. The final approval is announced in the Bulletin as well.

NOx means nitrogen oxides, the gases that come from burning fuel at high temperature. They cause smog and aggravate asthma. A permit sets a NOx cap in tons per year; it is the most the site may emit, and it decides which review the project gets and how much pollution control the engines must carry.

Water is permitted separately. Withdrawals in the Susquehanna basin go through the SRBC, which only regulates consumptive use above 20,000 gallons a day; in the Delaware basin through the DRBC; discharges through a DEP NPDES permit; and stream or wetland work through a DEP Chapter 105 permit. Many data centers say they use closed-loop cooling, buy water from a municipal authority, or stay under the SRBC threshold, so no per-project number is ever filed. That is why the water column is often blank.

What the permits are in Oregon

In Oregon the air permit is an Air Contaminant Discharge Permit (ACDP) from the Department of Environmental Quality. A Simple ACDP covers small sources, a Standard ACDP covers most data-center generator fleets, and the largest sources hold a federal Title V operating permit. DEQ also offers a streamlined data-center permit for backup generators. The Standard ACDP and its review report are where the numbers live: the engine count, the size of each engine, and the Plant Site Emission Limit, which is the annual cap on nitrogen oxides and other pollutants.

The state's own count comes from the Governor's Data Center Advisory Committee, whose September 2026 preliminary learnings document puts Oregon at about 123 active data centers in 2025, up from 8 in 2000, four in five of them inside an urban growth boundary, with 31 more in the process of siting (19 wholesale, 5 powered shell, 8 hyperscale) (pp. 4, 8). The same document says diesel backup generators are deployed "nearly universally" and may run up to 100 hours a year for routine testing within air standards; a declared emergency can exceed that (pp. 9–10). It also says what this site exists to fix: information about data centers is "fragmented across state agencies, local governments, utilities, and private entities," and the committee sees value in a state-hosted system covering backup power, emissions and facility locations (p. 14). The committee takes comment until October 24, 2026. Report OR-01 reads the permit record against that count.

Permits issued before late 2024 are posted on DEQ's older permit search as PDF files. Newer permits, modifications and every open public-comment notice live in Your DEQ Online, which has to be searched by hand. Oregon rows on this site started from the older search in September 2026; the newer portal is being worked through, and a row whose figures read "Not yet reviewed" means the permit is on record but its documents have not been read yet. Three Boardman permits have been read in full so far.

The 2026 executive order

On August 18, 2026 the governor signed Executive Order 2026-05. It covers data centers that would draw more than 25 megawatts, and it applies to applications submitted after that date, so the projects that filed earlier are reviewed under the old rules. For a covered project, DEP uses a template Consent Order that the developer signs before the permits move. The order also created the public DEP Data Center Permit Tracker and bars state agencies from signing non-disclosure agreements with developers.

In plain words, a Consent Order obliges the developer to say how big the project is and how much power and water it will use; to meet clean-power requirements for the electricity it draws; to hold community meetings and put its jobs commitments in writing; to use Tier 4 or zero-emission backup generators; and to install air monitors whose readings the public can see.

This site does not grade compliance with the order. It reports what the DEP documents say, and where a project has a Consent Order on file the record will link to it. If a promise made at a community meeting is not in a document, it is not on this site.

How to read the numbers

Each project shows up to four headline figures: generators, megawatts, tons of NOx per year, and gallons of water per day. To make them concrete, the site compares them to national averages. These are the exact factors, from scale.js:

One household draws 1.23 kW on average. EIA reports 10,791 kWh per residential customer per year (2022); divided by 8,760 hours (EIA FAQ).

One household uses 300 gallons of water a day. EPA WaterSense: the average American family uses more than 300 gallons per day at home (EPA).

One gasoline car emits 0.0024 tons of NOx a year. 0.208 grams per mile for light-duty gasoline vehicles in 2021, EPA's MOVES4 model as published by BTS (Table 4-43), times 10,599 miles per year for a short-wheelbase light-duty vehicle in 2021 (FHWA Table VM-1): 2,205 grams, or 4.86 pounds.

One passenger vehicle emits 4.73 tons of CO2 a year. EPA's 4.29 metric tons CO2e per vehicle (2022 data), converted to short tons (EPA equivalencies).

So Lancaster's 83-ton NOx cap equals the yearly tailpipe NOx of about 34,000 average cars, and Salem Township's 129,000 gallons a day is what about 430 households use.

What the comparisons are not: a NOx cap is a ceiling written into a permit, not a measurement of what came out of the stack. Backup generators do not run all year; the Homer City approval limits each emergency generator to 500 hours in any 12 months, and a diesel fleet's real emissions depend on how many outages and tests happen. Megawatts are nameplate capacity, the most the engines could produce, not what they do produce. The household and car figures are national averages, not measurements at the site.

What the evidence labels mean

Every figure on a record carries one of seven labels that says where the number came from:

Permit figure: The number is written in a DEP permit, plan approval, docket, or the Pennsylvania Bulletin notice for one; it is a term the company is bound by.
Official tracker: The number comes from the DEP Data Center Permit Tracker or another agency listing, not from the permit document itself.
Developer statement: The number was said by the company or its engineers, in an application, a press release, or testimony, and no agency has adopted it.
Press report: The number appears in a news story or a public FAQ and we have not found it in an official document.
Calculated: We computed the number from figures in a document, for example total megawatts as engine count times engine rating, and the evidence note shows the arithmetic.
Not published: No public document we have found states the number; the record says why the cell is blank.
Not yet reviewed: The ledger holds a number but nobody has yet traced it back to a document, so treat it as provisional.

Where the ledger does not carry a label yet, the site reads the evidence note and marks the label as inferred from it.

What each number measures

A figure is only useful if you know what kind of quantity it is. Each figure names one of six measurement types:

Permitted annual ceiling: The most the permit allows in a year, such as a NOx cap in tons; real emissions will be lower and depend on how often the engines run.
Proposed capacity: What the developer says it plans to build or draw; it may change before a permit is issued.
Nameplate generation capacity: The most the installed engines or turbines could produce at once, not what they produce over a year.
Actual reported measurement: A quantity someone measured or reported after the fact, such as metered water use.
Calculated estimate: A figure we derived from other figures, with the arithmetic shown in the evidence note.
Generator count: The number of engines or turbines named in the document, whatever their size.

The household and car comparisons under each figure are labeled comparisons, not measured impact: they convert a ceiling or a nameplate figure into everyday terms using national averages, and they say nothing about what actually came out of a stack or a pipe at the site.

How to act

Open a project on the map. If a comment period is open, the record shows the deadline under Permit. The Pennsylvania Bulletin notice linked as the primary document names the DEP regional office (Southeast, Northeast, Southcentral, Northcentral, Southwest, or Northwest) and the contact to send written comments to; comments must arrive within the 30-day window. You can ask DEP for a public hearing in the same comment. This site is independent and is not affiliated with DEP or any company named on it.

Sources and method

The ledger sheet is the source of truth; the map reads it live. Every row has an evidence column that says which document each number was verified in, which were inferred (for example, total MW as units times rating), and which are company or press statements rather than permit figures. Cells sourced from statements are labeled as such. Numbered sources sit on the sheet's sources tab, and each project record on the map lists the ones it cites.

Compiled from PA Bulletin notices, DEP plan approvals and technical review memos, the DEP Data Center Permit Tracker, SRBC and DRBC dockets, and NPDES notices. Found an error or a document we missed? Open the ledger and leave a comment on the cell.