Dark smoke rose above a data center in Ashburn, Virginia, over the July 4 weekend as a heat wave strained the regional power grid. The incident occurred at a Digital Realty data center, which activated diesel generators as part of PJM Interconnection's demand-response program to reduce strain on the grid during peak demand.
Immediate Action & Core Facts
- Diesel generators at a Digital Realty data center in Ashburn, Virginia, were activated on July 3 as temperatures reached 102°F, producing visible dark smoke. The company confirmed the generators were part of PJM Interconnection's demand-response program to manage grid stress.
- PJM's demand-response program incentivizes large electricity users, including data centers, to reduce consumption during peak times to prevent grid overload. Data centers account for about 5% of participants in the program, while manufacturers make up 43% of the capacity.
Deeper Dive & Context
Growing Data Center Footprint
Ashburn, known as "data center alley," hosts dozens of facilities operated by major tech companies like Amazon, Microsoft, and Equinix. A Business Insider analysis found that 176 new data centers were permitted in 2025, potentially requiring enough electricity to power millions of homes. This expansion has sparked debates about rising energy costs and environmental impacts.
Environmental and Economic Concerns
Critics argue that reliance on diesel generators for backup power contributes to air pollution and climate change. Elena Schlossberg, a northern Virginia activist, described diesel as "18th-century electricity," highlighting concerns about fossil fuel dependence during extreme weather events.
Grid Management and Demand Response
PJM Interconnection coordinates power generation, transmission, and demand-response programs for roughly 20% of the U.S. population. The program offers financial incentives to participants who reduce electricity use during peak demand, helping stabilize the grid. While data centers are a small fraction of participants, their energy consumption remains a focal point in discussions about grid reliability and sustainability.