A data center's backup generator can perform reliably for years or even decades if it is well maintained, but eventually a replacement or retrofit may be in order.

This could be because repairs have become more frequent and expensive, the facility's power needs have outpaced the generator's original capacity, or tighter air emissions regulations are on the horizon.

"I've seen cases where a major catastrophic failure occurs and you have no choice but to replace the generator," said Andrew Holmberg, chief engineer and director of innovation for ESI Total Fuel Management. "But what I see a lot more often is a facility that was built many years ago with a very low power density. Today, it has access to much more power than it's using, and its backup power infrastructure may no longer align with the facility's current or future requirements.”

Under those circumstances, a system replacement or upgrades may need to be considered, he said.

ESI helps data center clients navigate these decisions, which are rarely as simple as swapping an older generator for a newer, more powerful model, Holmberg said. Federal, state and local air regulations may impose stricter limits on new and modified generators than on units permitted under earlier standards.

Depending on the jurisdiction, permit requirements and engine application, a new or modified generator may need emissions-control technologies such as diesel particulate filters, diesel oxidation catalysts and selective catalytic reduction. These systems can add substantially to the cost and complexity of a replacement or retrofit project. In these cases, Holmberg said ESI works closely with clients to arrive at a "holistic" solution that takes into account both their capital and operating expenditure priorities.

"If they have a certain budget and these are the things they need to do to be in compliance, we help them prioritize and determine what they need to do first," Holmberg said.

It isn't unusual to see a data center operate with both older units permitted under earlier standards and newer generators equipped with the latest emissions-control technologies, provided each unit and the overall facility remain compliant with applicable permit conditions and emissions limits. Holmberg said ESI helps clients develop solutions that balance regulatory compliance, operational resiliency and budget constraints.

Filling Knowledge Gaps

Most data centers prefer to hold on to their legacy generators when doing so remains operationally and financially practical, Holmberg said. A decades-old generator may continue to run reliably if its duty cycle has been limited to brief monthly tests.

Still, even a reliable generator might not be up to the task of maintaining power at a facility whose operating requirements have increased greatly since it was built. Holmberg said ESI helps its customers manage the technical and operational logistics involved in the transition from an older model to a newer one or the process of retrofitting an older engine with new emissions controls.

"A replacement can affect much more than the generator itself," he said. "It may require changes to the fuel storage, pumping, controls, monitoring and emissions systems."

Holmberg said ESI helps clients plan for those changes, support their fuel handling and storage requirements, and coordinate the responsible removal, recycling or disposal of fuel and other fluids associated with the existing equipment.

ESI works with the client's mechanical, electrical and plumbing, or MEP, professionals and contractors, advising them on the best way to integrate a new generator and its fuel system into the facility's existing infrastructure.

"We've got a job right now where we're working for six different contractors on the same construction site, doing six different scopes of work," Holmberg said. "In cases like that, we fill in the knowledge gaps in areas where the large MEPs might not have the required fuel system or generator integration expertise."

Early Involvement Is Key

To get the most from ESI's knowledge base during a retrofit, Holmberg recommended that a data center owner and its MEP team involve the company early in the design process.

"That's always ideal because we can point out early in the project any pitfalls that we can help them avoid or answer questions like whether they can reuse an existing tank," he said. "A lot of what we do is educating project teams, flagging risks and helping them make informed decisions — often well before the physical work begins."

In the longer term, ESI can work with the client to establish a preventive maintenance program that supports reliability, extends equipment life and helps control long-term operating costs.

Holmberg said ESI is seeing an increasing number of calls to replace generator system components, whether on the fuel side or the emissions side. With regulations tightening, he said he expects to see more projects involving the addition or modernization of emissions-control systems for existing generators.

Whatever a client's challenge, Holmberg said ESI is dedicated to helping identify the most cost-efficient solution to keep its generators and supporting systems working optimally for years to come.

"The value is in automation, integration and understanding how the entire facility fits together. That's where we continue to win most of our business," he said.

This article was produced in collaboration between ESI Total Fuel Management and Studio B. Bisnow news staff was not involved in the production of this content.

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