Nashville’s city council will consider finalizing new legislation on Tuesday to regulate data centers, but a key environmental safeguard was stripped out earlier this month, with potentially serious consequences for public health and the environment.
In its current form, the legislation includes loopholes for fossil fuels. These could allow data centers to power up with on-site gas turbines or diesel generators, because the language permits an unlimited amount of on-site generation from fossil fuels during “emergencies,” which are not defined in the text. It also allows the Nashville Electric Service to grant special permission to data centers to use on-site generation from fossil fuels. For instance, when a data center is awaiting an infrastructure buildout to connect to the grid and wants to start up sooner, it could essentially fire up its own private power plant.
The amended bill the Metro Council passed two weeks ago is a “significant degradation of what was originally the primary environmental safeguard,” said Councilperson Rollin Horton, the sponsor of the legislation.
The original version limited data centers to using gas turbines or diesel generators on site for up to 72 hours during emergencies.
Data centers should use renewable backup, such as solar plus batteries, or shut down during power outages, Horton said, especially during ozone-promoting heatwaves.
“A heatwave is exactly when we don’t want to see data centers boot up gas turbines to power themselves,” he said.
Data centers could build ‘private’ power plants
Some data center facilities, like Elon Musk’s xAI facility in Memphis, get power from on-site or nearby gas turbines linked to high levels of nitrogen oxide pollution and climate-warming greenhouse gas emissions — comparable to the Tennessee Valley Authority’s largest coal plants. xAI initially requested 150 megawatts of power from Memphis’ local power company and TVA in 2024 and has since been expanding towards a size of 2,000 MW (2 GW), just shy of TVA’s Cumberland Coal Plant capacity.
Preventing that from happening in Nashville is part of the bill’s intent, but experts worry the vague language could consequently drive up air pollution in the city.
Councilperson Clay Capp introduced an amendment, published on the bill’s page Monday, that clearly defines “emergency use” of backup fossil fuel generation and prevents facilities from using fossil fuel generators as primary sources of generation.
“On-site power generation by any means—except for solar, wind, geothermal, and waste heat recovery—as a primary, parallel, or routine source of electrical power for data center operations shall be strictly prohibited,” the amendment reads.
The amendment also provides some incentives for data centers to source at least half of their power from renewable energy sources.
Some folks hope Nashville only passes the proposed moratorium on data centers Tuesday to allow more time to fine-tune amendments to the legislation. Last week, the Southern Alliance for Clean Energy submitted a letter to city officials urging similar amendments to those proposed by Capp, along with a 25-MW cap on backup generation to prevent large facilities from installing “what would effectively become a private fossil fuel power plant.”
“Large data centers can create electric demands comparable to those of entire cities,” the letter reads. “Nashville has a responsibility to ensure these facilities don’t use emergency-generation provisions to operate private power plants, create new pollution burdens or proceed without adequate utility infrastructure.”
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