What Does a Successful Market-wide Half-Hourly Settlement Migration Actually Look Like?

By Richard Carnall, Head of Consulting Services at ESG.

Completing migration is a milestone. Long-term success is measured by what happens afterwards.

For any major transformation programme, go-live is often seen as the finish line. Months, sometimes years, of planning, testing and preparation all build towards a single moment when new systems are switched on and the programme officially moves into production.

In reality, that’s where a different challenge begins.

Market-wide Half-Hourly Settlement (MHHS) is no exception. Over recent years, the industry has invested enormous effort preparing for one of the biggest changes to the electricity retail market since competition began. Suppliers have redesigned systems, introduced new processes and worked through extensive qualification and readiness activities to prepare for migration.

Those milestones have all been essential. But they don’t, on their own, determine whether MHHS has been successful.

The programme has always been about much more than implementing new technology. As Ofgem has set out throughout the programme, MHHS is intended to improve settlement accuracy, support greater flexibility across the electricity system and create the conditions for more innovative products and better customer outcomes. Achieving those ambitions depends on suppliers doing more than completing migration: it depends on being able to operate confidently once they’re there.

Technical readiness is relatively straightforward to measure. Systems either pass testing or they don’t. Qualification activities are either complete or outstanding. Operational confidence is different. It develops gradually, as people gain experience, new processes become familiar and organisations build trust in the way the new arrangements work day to day.

That’s why successful migration is about far more than technology.

The suppliers that transition most smoothly are unlikely to be those with the most sophisticated implementation plans alone. They’re the organisations that have prepared their operational teams as thoroughly as they’ve prepared their systems, while creating feedback loops to continuously learn and improve during the migration period.

Training, knowledge transfer, governance and practical experience all play an important role in helping new ways of working become business as usual rather than remaining programme activities.

This is one of the most interesting shifts beginning to emerge across the industry.

For much of the programme, discussions naturally focused on readiness milestones, qualification and migration planning. Increasingly, the conversation is becoming more operational. What happens once suppliers are live? How quickly do teams build confidence? Where do new processes work well, and where do they need refining? These are the questions that will shape the next phase of MHHS delivery.

They’re also the questions that will ultimately determine whether the programme delivers on its wider ambitions.

The benefits that have driven MHHS from the outset: better quality data, more accurate settlement, greater market flexibility and improved customer propositions — won’t appear simply because suppliers have completed migration. They will emerge gradually as operational maturity grows and organisations become confident enough to make full use of the capabilities the new market arrangements provide.

That process won’t happen overnight. Confidence is earned through experience. As more suppliers complete migration, the industry will naturally develop a richer understanding of what good looks like, sharing lessons, refining approaches and building on the experiences of those that have already gone before. Additionally, MHHS may create new challenges that will affect the market, and need to be assessed and resolved by not only individual suppliers, but potentially industry wide efforts.

So, while migration is an essential milestone, it isn’t the destination. The real measure of MHHS will only become clear over the coming months and years, as suppliers move beyond implementation and begin to realise the opportunities that motivated the programme in the first place. If that happens, the legacy of MHHS won’t simply be a new settlement model. It will be a more flexible, data-driven electricity market that’s better equipped to meet the changing needs of customers and support the transition to a smarter energy system.