Summary: Decommissioning legacy systems is emerging as a powerful sustainability strategy for organisations seeking to reduce their carbon footprint. With data centres projected to consume up to 8% of global energy by 2030, retiring legacy applications that hold predominantly unused data delivers measurable environmental benefits. This article explores the link between legacy system decommissioning and sustainability goals. Read now to know more.
Introduction
Sustainability has moved from a corporate aspiration to a regulatory obligation. With 85% of executives reporting increased investments in sustainability and frameworks such as the EU’s Corporate Sustainability Reporting Directive (CSRD) demanding transparent environmental disclosures, organisations are scrutinising every aspect of their operations for carbon reduction opportunities.
One often overlooked area is the IT estate, specifically the legacy applications that consume energy, occupy data centre space, and generate carbon emissions whilst delivering diminishing business value. This article examines how decommissioning legacy systems directly supports sustainability objectives and why it should feature prominently in every organisation’s environmental strategy.
The environmental cost of legacy applications
There are over eight million data centres globally, and their collective energy consumption is staggering. Research from the International Energy Agency indicates that data centre electricity consumption could increase fifteenfold by 2030, potentially accounting for 8% of global energy demand. Within this landscape, legacy applications represent a particularly wasteful category.
Studies suggest that only 10 to 15% of the data held by organisations is actively used. The remaining 85 to 90% is legacy information stored on servers that consume electricity around the clock, require cooling infrastructure, and generate carbon emissions, all for data that is rarely, if ever, accessed.
Energy consumption of legacy infrastructure
On-premises legacy servers are significantly less energy-efficient than modern data centre infrastructure. Older hardware consumes more power per unit of computation, generates more heat (requiring additional cooling), and lacks the energy-optimisation features built into contemporary equipment. Every legacy application that remains operational contributes to this inefficiency.
Carbon emissions from unused data
Each terabyte of data stored on active servers carries a carbon cost. When that data sits in legacy applications that no one accesses, the associated emissions serve no productive purpose. Decommissioning legacy systems eliminates these emissions at their source.
How legacy system decommissioning supports sustainability
SAP decommissioning and the retirement of other legacy applications deliver sustainability benefits across four key dimensions:
Improved IT operational efficiency
By retiring legacy applications and consolidating data into modern, energy-efficient archival platforms, organisations reduce the total number of servers, databases, and supporting infrastructure in their estate. Fewer active systems mean lower energy consumption and a smaller carbon footprint.
Enhanced equipment efficiency
Modern archival solutions leverage state-of-the-art storage technologies that deliver far greater capacity per watt of energy consumed. Migrating legacy data from outdated hardware to contemporary platforms improves equipment efficiency dramatically.
Data centre infrastructure optimisation
Legacy system decommissioning frees up physical data centre space, reducing cooling loads, power distribution requirements, and the overall environmental impact of facility operations. For organisations operating their own data centres, this can translate into measurable reductions in Scope 1 and Scope 2 emissions.
Enabling renewable energy adoption
Commercial cloud services and modern data centres are more efficient than smaller, on-premises server rooms. They also consolidate electricity demand at a scale that makes large-scale renewable energy purchases economically viable, something that smaller, distributed legacy environments cannot achieve.
Quantifying the sustainability impact
The environmental benefits of decommissioning legacy systems are measurable and reportable:
A 2025 partnership between major UK enterprises and IT asset management firms processed over 33.5 tonnes of decommissioned equipment, avoiding more than 322 tonnes of CO₂ emissions through reuse, refurbishment, and low-impact recycling
Organisations that migrate from on-premises legacy applications to cloud-based archival solutions can reduce energy consumption per data unit by a significant margin
Decommissioning outdated servers contributes directly to net-zero targets by eliminating ongoing energy consumption associated with maintaining unused infrastructure
For organisations subject to CSRD reporting or similar frameworks, these reductions can be quantified and disclosed as part of environmental performance metrics, demonstrating tangible progress towards sustainability commitments.
Sustainability and SAP decommissioning: A natural alignment
SAP itself has committed to achieving net-zero greenhouse gas emissions across its value chain by 2030, a target validated by the Science Based Targets initiative. This corporate commitment reinforces the alignment between SAP decommissioning and broader sustainability goals.
Organisations migrating to S/4HANA have a natural opportunity to decommission legacy applications as part of their transformation journey. By retiring ECC systems and consolidating historical data into efficient archival platforms, they simultaneously advance their migration objectives and their sustainability targets.
Circular IT practices
Responsible decommissioning extends beyond data management to encompass the physical hardware itself. Circular IT practices, including refurbishment, redeployment, and responsible recycling of decommissioned servers and storage equipment, further reduce the environmental impact of legacy system decommissioning. Innovative techniques such as bioleaching and urban mining can recover valuable metals from decommissioned assets using low-carbon processes.
Integrating decommissioning into sustainability strategy
To maximise the sustainability benefits of decommissioning legacy systems, organisations should:
- Audit their legacy estate to identify systems with the highest energy consumption relative to business value
- Quantify the carbon footprint of each legacy application, including power consumption, cooling requirements, and embodied carbon in hardware
- Prioritise decommissioning of the most energy-intensive and least-used legacy applications
- Select archival platforms that operate on energy-efficient, preferably cloud-based infrastructure powered by renewable energy
- Report sustainability gains as part of ESG disclosures, demonstrating the link between IT transformation and environmental performance
Conclusion
Decommissioning legacy systems is far more than a cost-reduction exercise; it is a meaningful sustainability initiative that delivers measurable environmental benefits. By retiring legacy applications that consume energy to store predominantly unused data, organisations can reduce their carbon footprint, advance net-zero commitments, and demonstrate responsible IT stewardship. As sustainability reporting obligations intensify and stakeholder expectations rise, legacy system decommissioning deserves recognition as a strategic pillar of corporate environmental strategy.