Data Center Size Categories (General Guidelines)
- Small: Under 10 MW power (enough electricity for hundreds to a few thousand homes). Water usage: Tens of thousands to a few hundred thousand gallons per day. Typically on 1–10 acres.
- Medium: 10–50 MW power (enough for thousands to tens of thousands of homes). Water usage: Hundreds of thousands to 1–2 million gallons per day. Typically on 10–50 acres.
- Large: 100–500+ MW power (enough for tens to hundreds of thousands of homes). Water usage: 1–5+ million gallons per day (equivalent to a town of 10,000–50,000 people). Often on 100–900+ acres.
- Hyperscale: 500 MW to over 1 GW+ (massive AI-focused facilities). Water usage: Multi-million gallons per day, sometimes using reclaimed water but with huge evaporative losses. Vast land and infrastructure needs.
DC Blox near Nashville Zoo (South Nashville/Grassmere Park) – Proposed
- Size: Medium (total ~50 MW planned across two buildings on ~23.5–24 acres).
- Electricity Usage: Up to 50 MW total (enough for roughly 30,000–50,000 homes); requires new substation and infrastructure.
- Water Usage: Significant evaporative cooling expected (hundreds of thousands to over a million gallons per day); potential discharge with biocides and chemicals.
- Environmental and Health Concerns: 24/7 noise, lights, and vibrations stressing zoo animals and nearby residents/schools; air pollution from backup generators (NOx, particulates linked to respiratory issues); grid strain raising local power costs; stormwater runoff and land conversion impacts.
Fisk University Data Center (North Nashville) – Proposed
- Size: Medium (~30 MW on a compact ~5-acre site).
- Electricity Usage: 30 MW (power for thousands of homes); part of campus redevelopment.
- Water Usage: Hundreds of thousands to millions of gallons per day for cooling, increasing local demand and potential discharge of treated water with biocides/poisons.
- Environmental and Health Concerns: Noise pollution affecting education and neighborhoods; water usage pressure and contamination risks; air quality impacts from generators; concerns about disproportionate community effects.
Cielo Project in Clarksville (Montgomery County) – Proposed
- Size: Large (~350 MW).
- Electricity Usage: 350 MW (enough for tens of thousands of homes; major grid strain).
- Water Usage: Likely 1–5+ million gallons per day for cooling, with risks of discharge containing biocides, chemicals, and pollutants.
- Environmental and Health Concerns: High energy demand could raise local electricity rates; air pollution from on-site power generation; water resource competition and contamination; large land use impacts.
Meta Campus in Gallatin (Sumner County, near Nashville) – Already Built / Expanding
- Size: Large (~300 MW on 800–900 acres with 1.7+ million sq ft of buildings).
- Electricity Usage: ~300 MW (powers ~200,000 homes); draws heavily from the grid despite some renewable matching.
- Water Usage: Hundreds of thousands to millions of gallons per day via evaporative cooling; still loses water and may involve chemical discharge.
- Environmental and Health Concerns: Increased local power and water bills; heat and air pollution from backups; conversion of large land areas; overall resource strain on the community.
xAI Colossus (Memphis area, including expansions) – Built and In Progress
- Size: Large/Hyperscale (initial 150–300 MW; expansions up to 1,000+ MW or more).
- Electricity Usage: Hundreds of MW to over 1 GW planned (major portion of local power; supported by on-site gas turbines).
- Water Usage: Up to 1–5+ million gallons per day (some reclaimed wastewater used, but massive evaporative loss and potential discharge with biocides/chemicals).
- Environmental and Health Concerns: Air pollution from natural gas turbines (NOx, PM2.5, formaldehyde linked to asthma, respiratory problems, and cancer risks in burdened areas); noise and vibrations; water contamination and aquifer concerns; lawsuits over operations and health impacts.
General Notes Tennessee has about 60 data centers total, mostly smaller ones that add up in cumulative impacts. Even efficient systems lose water through evaporation and can discharge pollutants. These facilities bring tech investment but often create debates over power bills, water supplies, air quality, noise, and limited long-term jobs versus local costs. Many areas are considering stricter rules on siting and resource use.
Closed Loop Water Systems Still Create Big Problems
Even so-called closed-loop cooling systems use substantial amounts of water and create pollution issues. While they recirculate water in sealed loops and can reduce consumption compared to fully open evaporative towers (sometimes by 70% or more), they still require ongoing makeup water to replace losses from small leaks, incidental evaporation, and especially “blowdown” — the periodic draining of concentrated water to prevent buildup of minerals and contaminants. For example, a large facility might still consume hundreds of thousands to millions of gallons per day depending on size and efficiency.
These systems rely on added chemicals to prevent rust, scale, corrosion, and microbial growth (like bacteria or algae that thrive in warm water). Common additives include corrosion inhibitors (such as nitrites, molybdates, or phosphates), biocides (like chlorine dioxide or bromine compounds), scale inhibitors, and sometimes glycols or antifreeze blends. Over time, these chemicals plus concentrated minerals and trace heavy metals (from equipment) build up, leading to blowdown discharge that can pollute waterways, overburden treatment plants, or affect local water quality if not pre-treated. This discharge risks harming aquatic life, raising salinity, or introducing toxins linked to environmental and health concerns. Many “closed-loop” setups are actually hybrid, transferring heat to a secondary evaporative system that still involves these issues.