By Joe Staib
Thousands of legacy data centers across North America sit dramatically underutilized. From a sustainability standpoint, reusing and retrofitting this infrastructure is the single most impactful step our industry can take.
As an industry, data centers are nothing if not resource intensive. Peruse virtually any media source and there is no shortage of articles about water, energy, and natural resource usage related to data centers. In her insightful white paper, Susanna Kass, data center advisor to UN Sustainable Development, stated, “A clean data center…is one that does not need to be built.”
But, what about those that are already built – those that are aging and not operating sustainably? A ‘Retrofit First’ mandate is the path forward. In fact, there is not only an environmental case to be made for this mandate, but a strong business case, too.
According to the International Energy Agency (IEA), data centers consume two-to-three percent of global electricity, and that figure is expected to double by 2030 as AI workloads proliferate. In the United States, the Department of Energy estimates that hyperscale campuses can use as much power as a medium-sized city, and the construction of new facilities is sparking growing backlash in local communities concerned about energy, water, and land use.
The result is an increasingly visible paradox: the very industry powering digital transformation is also being targeted, often rightly, for its role in rising power rates and increased grid strain. Even as we chase lower PUEs and cleaner energy, the upfront carbon in new construction – steel, concrete, copper, and chemicals – remains immense. Every new 100MW campus represents hundreds of thousands of tons of CO₂ emissions before a single server turns on.
The sustainability contradiction
Data center operators have embraced the sustainability challenge with vigor. Ultra-low PUE designs (<1.2), closed-loop water systems, and sustainable construction materials are now table stakes for new builds.
Yet the simple truth remains: every new data center consumes enormous quantities of natural resources and requires new layers of telecommunications, power, and fuel infrastructure just to ‘light it up.’
Meanwhile, thousands of legacy data centers across North America sit dramatically underutilized. Many of these enterprise and telecom sites operate at 20-40 percent of their designed capacity, with older power and cooling systems, but with excellent physical infrastructure and network connectivity.
They occupy locations that could deliver latency advantages for AI inference workloads, content delivery, and Edge computing without requiring the carbon cost of new construction.
The case for reuse
From a sustainability standpoint, reusing and retrofitting legacy infrastructure is the single most impactful step our industry can take. Every megawatt of IT load that’s migrated into an existing site avoids the manufacturing, transport, and installation of new chillers, pumps, generators, piping, conduit, and switchgear and prevents the waste disposal associated with demolition.
Sectors like healthcare, airports, and manufacturing have long proven that, with proper maintenance, mechanical and electrical systems can operate reliably for 30–50 years, and distribution piping can last a century. The data center industry – known for redundancy and resilience – can and should follow suit.
The good news is that most data centers were built to last. Their electrical backbone, chilled water systems, and structural shells are often robust, over-engineered, and meticulously maintained. With the right strategy, these can be rejuvenated to meet modern operational and environmental standards.
Retrofits done right
Of course, not all legacy sites are equal. Purpose-built telecom and enterprise data centers were often over-designed by today’s standards, with abundant floor loading, redundant cooling systems, power density, and connectivity. In contrast, older converted office or industrial sites may not justify major reinvestment.
Distinguishing between the two requires experienced engineering analysis to ‘fail fast’ where necessary, or to design a retrofit roadmap where it’s viable. For this reason, my company Enabled Energy, has recently introduced NextField, an advisory service that delivers a custom roadmap to transform inefficient and unsustainable brownfield facilities into their highest and best use.
Through our work, we’ve found that the oldest facilities often hold the most promise: thicker steel, stronger floors, larger conduits, and redundant layouts that were built for durability, not cost-cutting. Modern retrofits can leverage powerful new tools to breathe life into these aging assets:
- Predictive analytics and Fault Detection & Diagnostics (FDD) to re-use equipment and anticipate failures to optimize replacements.
- AI-driven energy management to maximize cooling and power efficiency in real time, allowing older plants to operate at competitive PUEs.
- Smart control retrofits (such as Niagara-based universal controllers) that enable open-protocol integration and sequencing optimization, which allows old CRACs and CRAHs to operate with modern scheduling protocol.
- Targeted mechanical and electrical upgrades that extend system life well beyond prior expectations.
When executed strategically, retrofits can reduce capital costs by 30–50 percent compared to greenfield construction, while accelerating time to market by months or even years. They also strengthen ESG reporting credibility, proving that sustainability and profitability can coexist.
A smarter, greener future
In the coming decade, the edge and AI inference layers will demand thousands of smaller, distributed sites close to end users. Legacy facilities – telecom central offices, enterprise data centers, and regional colocation sites – are perfectly positioned to meet this need.
With the right modernization investments, they can become the ‘AI edge’ backbone of the digital economy, offering the lowest-latency locations at the lowest environmental cost.
At the end of the day, I agree with Ms. Kass – the cleanest data center is the one that does not need to be built. For those that are already built, reusing and revitalizing the infrastructure we already have is not just a responsible environmental choice, it’s a sound business strategy that conserves capital, accelerates deployment, and aligns our industry’s growth with society’s expectations.
If we truly aspire to lead the world in innovation, then our sustainability story must begin with the stewardship of what we have.
To learn more about turning legacy data centers into thriving, sustainable NextField properties, please visit: www.enabledenergy.com/nextfield or reach out to schedule a transformation consultation for your brownfield fleet.
This article was originally published on DataCenterDynamics on October 21, 2025.
EN 
FR