By Bethany Brantley, Head of Sustainability, STACK Infrastructure, Co-Chair of the GRESB Foundation’s Data Center Working Group, and Christine Pries, Sustainability Manager, STACK Infrastructure, GRESB Working Group Member
The data center industry is undergoing unprecedented growth, fueled by soaring demand for compute power, from cloud services and video streaming to artificial intelligence and high-frequency trading. Once considered a niche within private markets, data centers, also referred to as digital infrastructure, have emerged as a core investment focus, drawing significant capital from limited partners and fund managers. Today, data centers are valued not only for their critical role in the digital economy, but also for their growing environmental and societal impacts. However, the rapid pace of global data center deployments has outpaced the broader data and sustainability community’s ability to establish consistent standards, metrics, and language to accurately define and measure sustainability performance. While often compared to traditional real estate assets (i.e., office buildings) or other non-commercial infrastructure (i.e., ports), data centers remain a challenging asset class to benchmark when applied to conventional sustainability frameworks, underscoring the need for a more tailored approach to evaluating their distinct environmental and social impact performance drivers.
The need for fit-for-purpose sustainability benchmarks
As we continue to focus on environmental and social performance, we have the opportunity to lead in developing meaningful, accurate, and forward-looking sustainability metrics. While the real estate and infrastructure sectors have long utilized third-party benchmarks for voluntary sustainability disclosure, these traditional frameworks often fail to reflect the distinctive characteristics of data centers. In many cases, legacy metrics overlook the technical sophistication and operational nuances of digital infrastructure, resulting in assessments that neither reflect true sustainability leadership nor enable meaningful comparisons across peers.
Traditional real estate benchmarks tend to prioritize metrics such as energy use per square foot, occupancy-based efficiency, and tenant engagement—factors that may hold limited relevance in highly automated, mission-critical data center applications. Similarly, infrastructure frameworks typically assume long asset lives and capital-heavy upgrade cycles, while data centers evolve rapidly to accommodate next-generation compute and network demands.
This disconnect presents a compelling opportunity to develop more tailored and accurate sustainability benchmarks. These benchmarks should reflect the data center sector’s leadership in areas such as embodied and operational carbon, power usage effectiveness (PUE), water usage effectiveness (WUE), waste minimization, circularity, grid interactivity, and climate resilience.
Why data centers are fundamentally different
Data centers are not passive assets; they are high-performance, 24/7 digital infrastructure systems engineered for resilience, uptime, and efficiency. Data center business models across the sector vary widely, including, but not limited to, colocation, wholesale, owner-operator hybrids, AI/ML, government, and hyperscale developments. These distinctions drive significant variation in design authority, operational control, and accountability for sustainability outcomes, which in turn influence how material issues are assessed, prioritized, and translated into measurable performance.
For example, a colocation provider typically controls key decisions around energy sourcing and facility infrastructure, such as the type of cooling systems installed. However, they have limited influence over PUE, which measures how efficiently a data center delivers power to its IT equipment. PUE compares total facility energy use to the energy used directly by the facility’s servers and computing hardware. In a colocation model, the provider manages the building and power delivery, while tenants control the IT equipment, determining hardware efficiency, utilization levels, and workload variability. These tenant-driven factors can significantly influence PUE, making it a less reliable indicator of the provider’s sustainability performance. In contrast, single-tenant, fully integrated facilities allow one party to manage both infrastructure and IT equipment, offering more control over efficiency outcomes. Without this distinction, benchmarking can unfairly penalize or misrepresent colocation providers in sustainability assessments.
Evaluating the full sustainability value of data centers
Best-in-class data centers are increasingly positioned to generate positive environmental value and transparency in addition to minimizing impact.
Though not publicly accessed like general office, commercial, or retail spaces, data centers exert significant influence on local infrastructure, particularly electric grids, water systems, and land use. Because of their long asset lifespans and capital-intensive nature, data centers become deeply embedded in the regions they serve. Communities are increasingly demanding transparency, inclusive hiring practices, investment in broader access to STEM education, and localized environmental stewardship in return.
Innovation introduces a critical, yet often underappreciated dimension to how data centers should be evaluated from a sustainability perspective, as they do not passively consume resources. Data centers have the potential to contribute to environmental and community resilience far beyond their physical footprint. Many operators are exploring creative local investment and engagement strategies, including:
- Waste heat reuse through district heating systems
- Grid-interactive capabilities, including participation in demand response and provision of ancillary services for grid stability
- Onsite renewable integration coupled with long-duration storage or flexible backup generation strategies
- Ecosystem co-benefits, like pollinator habitats or adaptive land design, that support biodiversity or community access
These innovations are not theoretical; they’re technically feasible today, at scales capable of delivering benefits far greater than the physical footprint of a data center facility or campus. These examples highlight that when innovation is embraced, data centers do more than consume resources—they enable shared value, which should be reflected in how sustainability performance is measured and benchmarked across the sector.
Educating investors: A strategic imperative
More than USD 73 billion in data center mergers and acquisitions closed in 2024¹, signaling institutional investors’ deepening interest in the sector. As ownership structures evolve, so too must the way investors engage with platforms on sustainability. Key considerations include:
- Accurate classification: Forcing data centers into real estate or infrastructure benchmarks obscures their unique performance drivers. Distinct categorization allows for more meaningful interpretation of sustainability data and avoids misclassification of risk or opportunity.
- Value chain dynamics: Data center developers typically control embodied carbon emissions through design, material selection, and construction practices. Operators influence operational emissions through energy procurement, maintenance, and IT system management. A unified benchmark must accommodate both perspectives.
- Tailored guidance: In the absence of tailored guidance, sustainability assessments may inadvertently reward superficial compliance or penalize innovation. Without shared language and sector-specific education, limited and general partner investors risk misjudging performance or underestimating value creation potential.
Designing with industry, for industry
Data centers operate within complex ecosystems where design, operations, and tenant usage are often shared responsibilities. Hyperscale contracts often distribute sustainability responsibilities across multiple parties. Effective benchmarking solutions must reflect these shared situations, making collaboration between stakeholders critical. Cross-industry alignment can ensure benchmarks evolve in lockstep with technical realities, driving transparency, comparability, and ultimately investor confidence.
Asset Impact
The GRESB/iMasons Data Center Working Group
As a member of the Infrastructure Masons (iMasons) Sustainability Committee, STACK’s Head of Sustainability led an initiative to establish a first-of-its kind strategic partnership between iMasons Climate Accord (iCA) and GRESB, a leading global benchmark provider across real assets and climate-critical industries, to develop the first global sustainability benchmark tailored to the unique operational and business model realities of data centers.
Together, the two organizations formed a strategic alliance, the iMasons-GRESB Data Centers Working Group, chaired by STACK’s Head of Sustainability, Bethany Brantley, and GRESB’s Chief Innovation Officer, Chris Pyke, and consisting of 30+ developers, operators, investors, tenants, consultants, and lenders—each contributing specialized expertise in areas such as water, carbon, energy, health, safety, and circularity.
Their shared goal is to create an assessment that is:
- Rigorous enough for investor-grade disclosure
- Realistic in terms of operator constraints and sector realities
- Responsive to the sector’s pace of technological advancement
- Inclusive of innovation and community engagement as value-added performance levers
This effort will produce more than a reporting tool; it will establish a foundation and shared language to help the industry articulate its unique and powerful impact story. For investors, it enables more accurate peer comparisons, deeper risk-adjusted insights, and stronger accountability. For operators, it offers a blueprint for internal improvement and transparent stakeholder engagement. And for tenants, it provides a consistent, comparable framework to evaluate both current and prospective providers.
A path forward: From pilot to full industry assessment
The collaboration between iMasons and GRESB has focused on identifying material sustainability priorities, emerging trends, and specific performance metrics that should be represented in the new global benchmark assessment. Furthermore, the assessment aims to create a common foundation and shared language for consistent, comparable measurement and communication of the industry’s distinct sustainability story.
A pilot of the new GRESB Data Center Assessment was launched in September 2025, with a full assessment set to be delivered through GRESB for wider market adoption in 2026.
The Pilot Assessment:
The Pilot Assessment will focus on aggregated, entity-level information, focused on capturing the following elements:
- Entity management: leadership structures, incorporation of sustainability into business practices, stakeholder engagement
- Performance modules: energy, carbon, water, health & safety, grid impacts, and community
- Certification summary: e.g., building certification, management recognition
- Innovation: cutting-edge practices, innovation pilots, and superior performance
During the pilot, the Working Group is looking for feedback from two core groups:
- Data center developers and operators:
- Are the proposed indicators and metrics relevant, material, and practical to report?
- Do they support constructive engagement between managers and investors?
- Data center investors and tenants:
- Are the proposed indicators and metrics relevant and material to your decision making (e.g., investment, leasing)?
- Do they support constructive engagement between managers and investors?
The 2026 full assessment and benefits of participation:
The team is working toward the release of a generally available assessment in the first half of 2026.
The full assessment will include:
- Data center-specific indicators and metrics
- Recognition for data center-specific best practices and performance levels
- Benchmarking and scoring insights to facilitate internal and external engagement
Dedicated materials and insights:
- Supporting resources, including a Data Center Reference Guide
- Access to GRESB Portal benchmarking insights
- Access to GRESB AP training platform
- Secure engagement platform for companies, managers and investors
The future of digital infrastructure depends on scaling capacity responsibly. The data center industry has an opportunity to set the standard for what sustainable, high-performance infrastructure should look like in the 21st century. Realizing that potential, however, will require wide collaboration, targeted education, and benchmarking tools built for the complexities of the sector, not borrowed from other asset classes.
Collaboration is key to making the emerging Data Centers Assessment and Benchmark successful.
Join our efforts
For information on how to get involved please contact us today.