Six critical issues, in priority order

Loudoun’s framework identifies six issues that any community should examine closely before approving data center development. They are listed here in the order of priority Loudoun assigns them:

1. Sound
2. Setback
3. Sight (appearance)
4. Power
5. Water
6. Emissions

Sound and setback top the list because, unlike water use or emissions, they are difficult or impossible to remedy once a facility is built and operating near homes. The fifteen best practices below are organized around these six issues.

Fifteen best practices

Loudoun’s white paper distills its experience into fifteen specific recommendations. We’ve grouped them by the six critical issues, with three foundational practices first.

Foundational — before any specific project

• Make sure the county’s Land Use Plan addresses data center performance standards — including the ones below — and that the Zoning Ordinance aligns with the Land Use Plan. Keep both current.
• Don’t allow data centers to be built “by right.” Require specific approval from the governing body for each project. (“By right” means a use is automatically permitted under zoning, without discretionary review.)
• Don’t sign non-disclosure agreements. Loudoun’s position is that a sound public process depends on public information.

Sound

• Conduct a noise study both before and after construction, measuring in both dBA and dBC. dBA (A-weighted decibels) approximates ordinary audible noise. dBC (C-weighted decibels) captures more low-frequency energy and is better at measuring the tonal, narrow-band, low-frequency hum that data center cooling equipment can produce.
• Adopt a noise ordinance that limits sound to a maximum of 50 dBA at the sending property line, and reduces tonal or narrow-band noise to background levels. (One option: limit post-construction noise to a set percentage of measured pre-construction levels.)

Setback

• If a site is near residential development — now, or anticipated in the future — require a setback of at least 500 feet. A setback of 1,000 feet is ideal.

Sight (appearance)

• Require natural screening, berms, and fenestration (window treatments) on principal facades.
• Limit building height and Floor Area Ratio (FAR) so facilities remain compatible with surrounding structures.
• Encourage microgrid design within the data center campus for future use. (A microgrid combines a large power consumer, a baseload power source, a backup power source, long-duration storage, and a grid connection.)

Power

• Require utilities to specify, in writing, the maximum power the data center is requesting and how the utility plans to deliver it — routing, overhead lines, substations, and so on. Require governing-body approval to exceed the stated maximum. (As a rough capacity guide, a 500 kV line can carry on the order of 2.1 GW; a 230 kV line on the order of 750 MW.)
• Site data centers near existing power lines, but no closer than twice the width of the line’s right-of-way.
• Require substations to be on-site or adjacent, and included in the project application. Don’t allow “by right” substation development, and don’t treat substations as an “accessory use” to a data center.
• For energy storage, require long-duration systems — at least 10 hours of storage — rather than lithium-ion batteries, which are not long-duration systems.

Water

• Require the data center and the water utility to specify, in writing, how much water the facility will use annually.
• Determine whether the facility will use air cooling, open-loop water cooling, or closed-loop water cooling.
• Determine whether it will use potable (drinking) water or reclaimed water.
• Determine how the facility will treat its wastewater, and whether the local treatment plant can adequately process it.

Emissions

• Require Tier IV backup generators, or Tier II generators fitted with Selective Catalytic Reduction (SCR). If the facility uses natural gas turbines, require SCR using ammonia as the catalyst. (SCR is a pollution-control technology that reduces nitrogen oxide emissions; generator “Tiers” are EPA emissions ratings, with Tier IV the cleanest.)

Loudoun County’s own summary of pros and cons

The white paper closes with Loudoun’s plain summary. It mirrors — from a practitioner’s standpoint — the fuller, sourced treatment on our Potential benefits and Concerns and questions pages.

Loudoun’s stated pros

• Very high tax revenue, depending on the local tax structure.
• Strong capacity to support community initiatives.
• Very low impact on everyday infrastructure — data centers add no schoolchildren and little road traffic.
• Good construction jobs during the building phase.

Loudoun’s stated cons

• Visually unappealing — buildings commonly run 60 to 100 feet tall, with large concrete walls. This can be partly mitigated with setbacks, berms, greenery, and fenestration.
• Noise, both dBA (normal hearing range) and dBC (tonal, narrow-band, low-frequency hum).
• High and growing power consumption — a rule of thumb is roughly 150 MW for every one million square feet of facility.
• Water consumption.
• Light pollution.
• Power transmission lines.
• Power substations.

How this applies to Tooele County

Tooele County’s tools are different in name but similar in function: the County General Plan, the zoning ordinance, and the review process that runs through the Tooele County Community Development Department, the Planning Commission, and the Tooele County Council.

Residents and officials can use Loudoun’s framework as a checklist — asking, for any specific project, whether it meets these benchmarks for sound, setback, appearance, power, water, and emissions. Many of these questions are already built into the Residcent Question Handout.

For developers, the For Business page describes what a complete Tooele County application should address — and most of the items Loudoun recommends overlap directly with it. Coming to public hearings with clear, written answers to these questions tends to shorten the review process, not lengthen it.