Developers who want to build data centers in Birmingham have new rules to follow after the City Council passed zoning changes earlier this summer in a contentious meeting.
As the city prepares to review future projects under those rules, here’s a closer look at what the ordinance requires — particularly for the largest facilities.
The ordinance breaks data centers into three categories: micro, medium and hyperscale.
The largest are hyperscale data centers, which are defined as facilities larger than 200,000 square feet and/or using more than 30 megawatts of electricity.
In general, the bigger the data center, the more restrictions it faces.
The city lists 20 requirements for hyperscale facilities, covering everything from water and electricity use, to noise, lighting, and building setbacks.
Restrictions on water use
Hyperscale data centers must use closed-loop cooling systems, meaning the same water is recycled rather than constantly replaced with water from the outside.
Developers also have to tell the city how much water they expect to use, where that water will come from, and whether the city’s water and wastewater systems have enough capacity.
“Environmentalists in public meetings recommended to the city of Birmingham in your ordinance, you should make sure they use closed-water-loop systems,” Woodfin told WBHM. “Well, it’s in the ordinance, so that exists.”
Rules on power
The ordinance does not allow fossil fuel generators to serve as a data center’s normal source of electricity.
Natural gas and diesel generators can be used during power outages and emergencies, as well as for testing and maintenance. They cannot routinely generate electricity for the facility or the power grid.
Battery storage is allowed, including batteries charged from the grid or from on-site solar power.
Developers also have to identify the utility companies serving the project and provide information about new substations, transmission lines, and other electrical infrastructure the facility will need.
Do I have to see it?
The ordinance requires hyperscale facilities to screen generators, cooling equipment, substations, transformers and other mechanical equipment from public view.
That screening can include walls, fencing, landscaping or the design of the building itself.
What about noise?
Hyperscale facilities must have a noise study before construction and another one after construction. Both are intended to show whether the facility complies with the city’s noise requirements.
Woodfin said the ordinance also requires buffers and other measures to limit noise reaching nearby neighborhoods.
“Our ordinance is very detailed about you have to be very intentional about creating buffers and sound barriers and landscape buffers,” Woodfin said.
Limits on where the biggest facilities can go
A hyperscale data center must be at least 500 feet from residential and urban neighborhood areas and 1,000 feet from major transit stations. The facility must also be on a lot of at least five acres.
Developers have to provide the city with information about the facility’s expected size, electricity use, water consumption, cooling system, and backup power. That includes the project’s ultimate buildout if the facility is planned in phases.
Developers must notify property owners within 500 feet by certified mail of a new or expanded hyperscale facility.
Does every data center get a public hearing?
No.
A hyperscale data center does not automatically have to go before a board for a separate public hearing.
The final ordinance removed a special-exception requirement that had been included in an earlier version of the proposal.
Instead, the approval process depends on the project and the zoning district where it is located. Projects that do not require a special exception can go through the regular permitting process, provided they meet the ordinance’s conditions.
That means the size of a project alone doesn’t determine whether the public gets a hearing.
What if a project changes?
The ordinance gives the city an opportunity to review a project if it changes significantly.
Increasing a facility’s building size, electrical demand, water use, cooling capacity, or backup power beyond what was approved can be considered a material change in use.
That can trigger another review to make sure the project still meets the city’s requirements.
What’s still unclear?
The ordinance lays out a long list of requirements for getting a data center approved. The city’s zoning and code enforcement staff are responsible for administering and enforcing the zoning rules.
But questions remain about what happens after a facility is up and running.
For example, the rules establish requirements around projected water use, electricity demand, cooling systems, and noise. They do not spell out how the city might monitor data centers to see if facilities are still complying.
WBHM reached out to the city to speak with officials on that issue, but city leaders did not make anyone available.
