The Challenge
SAP ECC 6.0 IS-U sits at the core of the client’s market platform. With standard SAP support ending, the organization launched a modernization programme to secure the platform’s future while protecting continuity for the gas market.
The first proof of concept highlighted the scale of the challenge. It identified more than 40,000 compliance items requiring attention, significant manual remediation and a potential production downtime window of more than seven days. For a platform supporting industry-wide billing, settlement and market data, that level of disruption was not acceptable.
The issue was not simply how to upgrade SAP. The client needed to answer more fundamental questions:
- Could the current SAP core be converted to SAP S/4HANA for Utilities without introducing material technical or operational risk?
- How much data and customization needed to move, and what could be reduced before migration?
- Could the migration be completed within a downtime window that protected market continuity?
- How could the organization create a supported SAP foundation while retaining the flexibility to simplify and modernize the wider architecture over time?
The answers needed to stand up to technical scrutiny, business review and regulatory expectations.
Resulting Solution
Resulting led an evidence-led Solution Definition Project to test the preferred migration hypothesis and give the client a reliable basis for the next stage of its modernization programme.
The proposed route was a two-step approach:
- Establish the foundation: Convert the SAP core from SAP ECC 6.0 IS-U to SAP S/4HANA for Utilities through a brownfield migration, with minimal change to customer-facing interfaces.
- Optimize and simplify: Progressively modularize the wider architecture, introduce best-fit components where they add value and create a more flexible platform for future industry reforms.
The first step had to be proven before the second could begin.
Proving the migration path in practice
A segregated cloud environment was created using a representative export of the client’s pre-production SAP system. The environment was rebuilt and converted to SAP S/4HANA for Utilities using a production-like approach.
The proof of concept tested the application, data and technical conversion path. Post-migration validation confirmed that:
- The brownfield conversion was technically feasible.
- Data integrity was maintained, with no inconsistencies identified.
- Sample billing processes produced consistent results before and after conversion.
- A downtime window of approximately 21 hours was observed in the proof of concept.
This moved the conversation from a theoretical migration estimate to evidence from the client’s own environment and data.
Assessing the wider landscape
The proof of concept was supported by a broader set of technical and functional assessments. Resulting coordinated input from SAP and specialist migration, integration and code remediation partners to build a complete view of migration readiness.
The work covered:
- SAP readiness checks for simplification items, add-ons and business functions.
- Custom code analysis to identify compatibility issues, remediation requirements and opportunities for automation.
- Data volume and object analysis to understand the factors driving migration runtime and cutover risk.
- Near-zero downtime analysis using specialist migration tooling and techniques.
- Integration and microservices assessments to test the viability of future architecture options.
- Application and process analysis to identify the changes needed across the wider landscape.
The analysis brought hidden complexity into view. More than 45,000 custom objects were profiled, with around 59% identified as unused or obsolete. Data housekeeping and archiving opportunities were also identified, helping the client understand how to reduce the volume that would need to be processed during migration.
Designing for continuity first
The recommended migration approach uses a Near-Zero Downtime methodology to load and validate data ahead of the final cutover, while the existing ECC system remains operational. A final delta load and technical conversion can then be completed within a controlled downtime window, followed by reconciliation across key finance, billing and market settlement processes.
The result is a migration strategy designed around the realities of a mission-critical gas market platform, rather than a standard template. It protects continuity during the foundation move and leaves room for a measured modernization journey afterwards.
Benefits Delivered
A migration route backed by evidence: The Solution Definition Project confirmed that the move from SAP ECC 6.0 IS-U to SAP S/4HANA for Utilities is technically feasible and operationally achievable across the application, data and integration layers.
Downtime reduced from days to hours: The proof of concept achieved an observed downtime window of approximately 21 hours. Further analysis indicated that a production window of around 25 hours could be achievable, compared with the initial estimate of more than seven days.
Data integrity confirmed: No data inconsistencies were identified after the proof of concept conversion. Sample billing processes produced consistent results before and after migration, giving the client a stronger basis for planning the production move.
No material blockers identified: The assessments found no material barriers across the application, data or integration layers. The evidence showed that the preferred migration hypothesis could proceed with appropriate planning and preparation.
Continuity protected through a two-step strategy: The client can first establish a supported and secure SAP S/4HANA foundation, then simplify and modularize the wider architecture in a controlled way. This avoids forcing every transformation ambition into the initial cutover.
A clearer path to future change: The integration and microservices assessments identified viable options for improving flexibility, interoperability and data accessibility as the gas market continues to evolve.
A stronger basis for governance and confidence: The client now has a fact base for migration planning, technical design, risk management and future investment decisions. The result is a regulator-ready roadmap built on evidence rather than optimism.
Conclusion
When the platform behind a national market needs to change, confidence cannot come from a slide deck alone. It has to come from testing the migration against the real system, the real data and the real operational constraints.
The Solution Definition Project gave the client that evidence. The brownfield proof of concept demonstrated a viable path to SAP S/4HANA for Utilities, confirmed data integrity and reduced the expected downtime from more than seven days to around one day. The wider analysis showed that there were no material blockers to the preferred route and created a practical basis for the next stage of planning.
The work also separated two decisions that are often bundled together. First, establish a stable and supported SAP foundation. Then, optimize and modularize the wider architecture with the benefit of experience and evidence.
That is how you modernize a mission-critical platform without putting continuity at risk.
If your SAP S/4HANA programme involves complex data, strict availability requirements or an immovable support deadline, talk to us.
