CASE STUDY

Preparing a critical infrastructure utility for a high-risk CIS replacement

See how we helped a major U.S. natural gas utility prepare for a core Customer Information System replacement while safeguarding billing integrity, operational continuity, and regulatory compliance.

A large U.S. natural gas utility began replacing its aging Customer Information System, a core platform supporting billing, customer operations, and regulatory reporting for millions of customers.

However, decades of tightly coupled integrations, undocumented dependencies, and manual workarounds created significant risk, requiring a modernization approach that could enable system replacement while maintaining operational stability and regulatory compliance.

THE OPPORTUNITY

The organization aimed to successfully execute a high-risk Customer Information System replacement while creating a clear, governed view of integrations, dependencies, and remediation needs to enable long-term modernization and operational resilience.

THE CHALLENGE

They needed to navigate deeply interconnected legacy systems, limited documentation, and strict regulatory requirements without disrupting billing accuracy, revenue flow, or customer trust during a complex system transition.

THE PROBLEM

Managing legacy complexity under regulatory and operational constraints

Implementing a modern SAP Customer Information System required integrating more than 50 legacy applications with varying levels of technical maturity, documentation, and readiness. Many interfaces had evolved incrementally over decades to support specific rate plans, service territories, and operational processes, creating a highly interdependent ecosystem.

THE SOLUTION

Bringing control to a complex modernization effort

TSG partnered with the utility to de-risk the integration and remediation scope of the CIS replacement by establishing a validated understanding of the legacy environment and defining a clear path to the target state. The work built upon prior assessment efforts while updating foundational artifacts to reflect current conditions and anticipated future needs.

Establishing a reliable view of the legacy landscape

TSG reviewed and refreshed the legacy systems inventory developed during their earlier assessment, confirming system roles, ownership, dependencies, and relevance to the replacement program. The inventory spanned customer engagement platforms, meter data systems, financial and payment solutions, field operations tools, regulatory programs, analytics environments, and third-party services.

By documenting system purpose, dependencies, integration points, and readiness considerations, the client gained a reliable foundation for prioritizing remediation, sequencing workstreams, and assessing risk across the broader ecosystem. The effort transformed fragmented institutional knowledge, often held within individual teams, into a governed enterprise asset supporting coordinated decision-making.

Clarifying existing interfaces and dependencies

TSG refreshed the inventory of existing interfaces between the legacy CIS and dependent systems, including those marked for replacement. This effort uncovered previously undocumented connections that could have affected billing cycles, outage notifications, or payment processing if overlooked.

Defining the target integration architecture

TSG developed a comprehensive inventory of future-state interfaces between the new SAP CIS and retained systems, aligned with business requirements for rates, meter data, customer engagement, and financial reporting. Documenting expected data flows enabled coordinated planning across technology, operations, and regulatory stakeholders.

This future-state view provided a foundation not only for the CIS replacement but also for subsequent modernization initiatives across the customer and operational ecosystem.

Identifying remediation requirements early

Many legacy systems required modification to function within the new architecture. TSG identified systems needing remediation, defined the scope of required changes, and estimated the level of effort needed to complete them. Surfacing these needs early reduced the likelihood of late-stage surprises that could derail timelines or budgets.

Providing independent expertise and sustained support

Throughout the effort, TSG served as a trusted advisor and technical partner, supporting stakeholders in evaluating options, validating assumptions, and maintaining alignment as the program progressed. This continuity helped preserve institutional knowledge, accelerate decision-making, and reduce execution risk across phases.

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Strategic impact

Advancing modernization while preserving reliability and trust

The initiative transformed a high-risk replacement effort into a controlled program capable of delivering long-term benefits without compromising day-to-day operations. It also established a framework for managing future technology changes in a complex, regulated environment.

The work enabled the utility to:

Advance CIS replacement while protecting revenue collection
Maintain billing accuracy across complex rate structures
Reduce exposure to customer dissatisfaction and regulatory scrutiny

Most importantly, the utility moved forward with confidence, strengthening its ability to adapt to changing regulatory requirements, customer expectations, and technology opportunities while maintaining the reliability expected of a critical infrastructure provider.