The Problem of Legacy Systems in the New Energy Industry Landscape 

This article was authored by Drew Green, CTO of ESG Global

As Chief Technical Officer of Energy ESG Global, I spend much of my time with suppliers who are wrestling with rapid change.

The UK energy market is moving from a world of monthly meter reads and relatively simple tariff structures to a dynamic, data-heavy system shaped by Market-wide Half-Hourly Settlement (MHHS), faster switching, the Smart meter rollout, and the growth of flexibility markets.

This is a major shift for Industrial & Commercial (I&C) suppliers. Complex pass-through contracts, multi-site portfolios, corporate Power Purchase Agreements (PPAs), tolerance bands, and risk-managed pricing structures all demand a level of billing accuracy and data integrity that legacy systems were never designed to handle.

At the same time, customers expect accurate bills, flexible pricing and innovative propositions such as time-of-use tariff structures and behind-the-meter optimisation.

Regulators expect robust controls, audit trails, and timely reporting. Boards expect margin protection, tighter cost-to-serve and disciplined allocation.

Margins are tight, and in this environment, system architecture is no longer just an IT concern, it’s a large commercial one and increasingly a growth constraint.

Many of the systems still in use across the UK market weren’t built for this level of complexity, resulting in operational drag, revenue leakage, compliance risk, and delayed innovation.

Why Legacy Systems Are Failing I&C Suppliers

In my experience, there are five recurring weaknesses.

1. Fragmentation Across the Stack

The first and most obvious challenge is fragmentation. Over the years, suppliers have assembled stacks that are built up of pricing engines, billing solutions, CRM capability, industry orchestration and integration, from different vendors, stitched together with custom integrations and in many cases supporting spreadsheet data. This may be enough if you have a narrow product set, but it breaks down when you need support in today’s market complexity.

In I&C portfolios, we often see a common problem in non-integrated environments: a product can be priced accurately but can’t be billed in the same way. Complexity doesn’t map cleanly across pricing through to billing and settlement, so manual corrections follow.

That eats away at your margins, increases your dispute volumes, and inevitably weakens your customers’ trust in you as a supplier.

2. Data Models Designed for a Different Era

Many legacy I&C platforms were built around residential systems, where a monthly meter read was sufficient. This makes them ill-equipped for dealing with the data volume and granularity of Market-wide-Half-Hourly-Settlement (MHHS), while the signals required for flexibility, EV charging, and behindthemeter assets are even more challenging to implement.

Systems designed to disaggregate sparse monthly data into something useful will struggle under this pressure.

Instead, architectures that start with granular interval data and aggregate intelligently are far more resilient.

3. Cost-to-Serve and Operational Pressure

Legacy systems also make your day‑to‑day operations harder than they need to be. Your teams have to spend too much of their time reconciling reports from different modules, hunting for missing data, or manually resolving exceptions from market messaging.

Different teams feel this in different ways:

• Finance sees the impact in month-end delays, exception handling and revenue leakage.
• Operations feel it through disputes, settlement corrections and customer escalations.
• IT face a queue of break/fix and integration tickets.

When your systems require heavy human intervention to complete routine industry processes, you’ve basically embedded inefficiency into your operating model. Over time, that can massively constrain your capacity for innovation and growth.

4. Compliance and Market Interactions Risk

The UK energy market relies on tight integration with the Data Transfer Network (DTN), the iX Network, the Central Switching Service (CSS), and the DCC for smart metering and multiple trading and payment gateways. These include critical national infrastructure components with strict security and audit requirements.

If your internal systems aren’t aligned with what the industry recognises about a site, they’ll act on the wrong assumptions. For example, if your billing system and lifecycle system are out of sync with the industry position, then you end up with deviations in the data that results in local exceptions and misalignment across the market.

The resulting rework, penalties, and reputation risk can be a considerable challenge. If you’re managing large demand portfolios, small inaccuracies can quickly scale into considerable financial liabilities.

5. Fear of Migration and Strategic Paralysis

Even when your leadership team recognises the need to modernise, fear of migration can stall progress. Data quality is rarely perfect, and some suppliers have been burned by previous big‑bang replacements. That hesitation is understandable.

However, postponing modernisation doesn’t remove risk: it compounds it. We know migrations are difficult, which is why standardisation matters. Our philosophy at ESG is to set a clear, repeatable target format and work collaboratively to get there, using proven ETL (Extract, Transform, Load) tools and, when appropriate, industry processes to cleanse data at source.

Legacy systems also limit your strategic agility. Most suppliers want to enter new markets, launch flexibility propositions, and scale portfolios without adding proportional cost. But patchwork systems carry high IT overheads, limited reporting, and a lack of real‑time visibility across your billing, pricing and customer operations.

The result is stalled decision‑making and lost opportunities.

What Good Looks Like: A Modern Platform Pattern

We’ve worked closely with UK suppliers to define what platform architecture the new market genuinely requires. In my view, five characteristics are essential:

1. End-to-End Integration

It starts with being end-to-end and truly integrated. Pricing, billing, CRM, market orchestration and industry interaction must run from the same constructs, so all your tariffs, contracts, and deals can be billed exactly as promised. This removes a significant source of revenue leakage and manual intervention.

2. Native Market Interaction

Commissioning a meter or initiating a change of supply should trigger compliant industry flows without users needing to understand, for instance, DTN flows or CSS processes.

Your market integration should be embedded and auditable by design, not bolted on through potentially fragile connectors.

3. API-First, Event-Driven Architecture

An API‑first, event‑driven approach enables modularity and makes you more resilient. The platform’s components can scale independently, and you can phase transitions.
API architecture can integrate with your existing CRM and billing tools without destabilising your core processes.

All this supports your transformation without unnecessary disruptions.

4. Scalable Data Foundations

The platform’s data layer has to match this philosophy: relational databases are great for process integrity. However, high-volume interval data must scale independently in cloud storage environments that are designed for potentially trillions of records.

Equally important is controlled accessibility. You need timely, trustworthy data for board reporting, forecasting and scenario modelling, portfolio risk management, and real-time operational visibility.

Trapping data in silos diminishes its value, so the right platform should also make it easy to both stream cleansed data into data lakes and to curate a reporting store for self‑service analytics.

5. Exception-Based Operations

Baked in automation needs to be the default so your teams can focus on genuinely complex decisions. Automating as many routine industry processes as possible will reduce your cost-to-serve and increases your teams’ capacity.

Dealing With Flexibility Demands

The shift to flexibility is a huge opportunity for energy suppliers in the UK.

Residential portfolios are adopting EV charging, solar, and batteries, while I&C customers are demanding more sophisticated demand management and export structures. This means the underlying data and billing requirements are converging.

I&C complexity is effectively becoming the blueprint for the wider market. As a supplier, intelligent automation, data integrity, and embedded flexibility logic at scale will leave you better positioned to launch innovative propositions without increasing your operating costs.

Looking Ahead

The next phase of the energy market will reward suppliers who can execute quickly, control cost‑to‑serve, protect margins, and innovate without compromising on compliance.
Legacy platforms will continue to struggle as market complexity rises and customer expectations and demands keep climbing.

Choosing a modern, integrated, and scalable platform isn’t just about reducing technical issues. It turns challenges into opportunities. New tariffs can be launched faster, settlement risk can be managed more confidently, and you gain the clarity and insight needed to grow.

In the end, your system decisions shape your commercial outcomes. If your organisation is held back by ageing systems, manual reconciliations and an inability to bill what you can price, it’s time to move on.

Find out more about why Titanium is the modern platform you need.

FAQs

How does Titanium help move beyond fragmented legacy systems?

Titanium brings billing, pricing, CRM, and market operations into a single, modular platform, reducing silos, manual workarounds and integration headaches. It helps ensure what can be priced can be billed accurately by aligning core processes, which supports better data integrity, lowers cost-to-serve, and strengthens operational control.

Can Titanium support transformation without a disruptive big-bang migration?

Yes. Titanium’s modular, API-first architecture supports phased transformation and integration with existing systems, helping change happen in manageable stages. ESG’s approach uses clear target formats, proven ETL tools and collaborative delivery to reduce disruption and build confidence through the migration process.

How does Titanium support market change and flexibility opportunities?

Titanium is designed to help suppliers stay agile as market demands evolve, with embedded market interaction, scalable data foundations and automation across routine processes. Its flexibility market capability supports automated onboarding and registration at scale, helping suppliers enter new markets, remain compliant and unlock new revenue opportunities.