The Environmental Impact of Data Centers

At the last meeting of the Potomac Watershed Roundtable Julie Bolthouse, Director of Land Use, at the Piedmont Environmental Council gave a presentation titled "The Environmental Impact of Data Centers.” The Piedmont Environmental Council (PEC) has extensively documented the environmental impact from data centers, in Virginia, which hosts the world's largest concentration of data centers in the world. I would like to present a few highlights from her talk.

Data Centers are no longer the office parks of the last century that employed lots of people (remember AOL, now long gone). They are now hyperscale behemoths which employ only a handful of people for landscape, security, and a few operators. According to PEC research, the expansion of the data center industry poses significant risks to energy grids, water resources, air quality, and local ecosystems.

This is especially true in Virginia which has three times the mega watts (MW) and square feet of data centers than anywhere else in the nation. Currently, there are about 70 million square feet of data centers now operating in Virginia; however, there are 285 million square feet of data centers that are approved or in the pipeline.

Along with the massive increase in square footage of data centers, is skyrocketing energy demand. In 2025 data centers used 24 Gigawatts (GW) of electricity in Virginia by 2030 data centers are forecast to use 57 GW in Virginia. A gigawatt (GW) is equivalent to the energy generated by a nuclear reactor or gas plant. Dominion Energy of Virginia has received 70 GW of load request and have 48 GW in contracts for power-21 GW of this is in the final stages of contract.

Due to the demand strain, Dominion Energy is providing incremental load. For example, when Dominion Energy receives a request for 300 MW of power, they start the customer with 25 MW and Dominion Energy vamps them up over time.

This all seems wildly out of control and unplanned be each locality only looks at land use. The locality does not look at the power demand or where the power lines will go. More concerning is that the cost of transmission lines and generation is spread amongst all power customers. The old model allocated costs assuming that residential growth is what was driving the growth in power demand, and large customers like data centers receive discounted rates. Of the transmission projects on Dominion Energy’s books:

• $2.4 billion for transmission lines that will provide power only for data centers
• $3.3 billion for transmission lines that will server data centers and other customers
• $1.8 billion for transmission lines that will serve others

Data centers are also impacting the air quality in our region. Data centers rely on massive diesel backup generators for outages. In Loudoun County alone, permits exist for over 4,000 generators with a combined capacity of 11 gigawatts. In all of Virginia there are 10,000 Tier II permitted diesel generators. In Sterling alone, there are 2,000 older Tier II diesel generators. . A PEC-commissioned study found that on-site power emissions could result in up to $99 million annually in health-related damages due to premature mortality and respiratory diseases. This is mostly from PM 2.5 micrograms/m3.

New power plants proposal are also impacting air quality. PJM is modeling that Virginia is going to triple their power generation and that is going to come primarily from gas turbines with data centers installing on-site gas turbines. DEQ recently changed their rules to allow data centers to essentially use their back up generators as peaker plants to avoid tanking down the grid.

Finally, water. Depending on the cooling system, a single data center can consume 3–5 million gallons of water daily, 60%-80% of this water use is consumptive. Julie warns that this usage stresses local watersheds and the Potomac river, especially during drought conditions which we have been experiencing the past few years. In Loudoun, the reclaimed water from the wastewater treatment plant is maxed out at 697 million gallons/day (90% of this is going to data centers). So the Loudoun County data centers draw an additional 952 million gallons of potable water to cool the data centers. While data centers represent only 1-2% of the water drawn from the Potomac River on average, in summer, data centers are 9-12% of the consumptive use of the Potomac River.

The wastewater from data centers contains high levels of salinity and total dissolved solids, corrosion inhibitors, biocides, chlorine, phosphates and other additives. The wastewater treatment plants can’t effectively remove all these contaminants.

The Key Environmental Impacts 

In summary Julie highlights several critical areas where data centers affect the environment:

• Energy Consumption & Grid Strain: This demand from data centers has led Dominion Energy to delay the retirement of coal plants and expand natural gas infrastructure to maintain reliability, threatening state climate and decarbonization goals.
• Water Usage: Depending on the cooling system, a single data center can consume 3–5 million gallons of water daily. This growing water use stresses local watersheds and the Potomac River, especially during drought conditions.
• Air Quality & Public Health: Data centers rely on massive diesel backup generators for outages. These generators increase the small particulate matter in our air.
• The data center buildout converts thousands of acres of agricultural land and forests into impervious surfaces, leading to increased stormwater runoff and pollution in local waterways.
• Local Community Impacts: Proximity to residential areas brings persistent noise pollution from industrial cooling fans and light pollution from 24/7 facility operations.