This weekend, England and Scotland meet again in the Six Nations Calcutta Cup.
At Vekta Group, that rivalry takes a familiar shape. Gordon Thomson (Technical Advisory Team Lead), proudly Scottish, and Charles Balderson (Electrical Project Manager for offshore and onshore wind and new technology projects, consultant and founder of Vekta Group), firmly English, work side by side - analysing the same systems, solving the same problems, and occasionally trading jokes about battered Mars bars and Greggs across the office.
On match day, loyalties are clear. On Monday morning, they’re back doing exactly the same thing: trying to make renewable energy and infrastructure work better.
Somewhere between the banter, biscuits and pints on a Friday afternoon sits a very real dividing line- not on the rugby pitch, but on the power network. In energy terms, the most consequential divide between Scotland and England isn’t cultural. It’s technical.
The B6 boundary separates the Scottish electricity network from the electricity system in England and Wales. It is currently the most constrained transmission boundary in Great Britain, limiting how much electricity, particularly renewable wind generation, can flow south to where demand is highest.
When wind output in Scotland is high and the network cannot transport it, system operators are forced to curtail generation. At the same time, generation further south is paid to increase output to meet demand. The result is an outcome that feels counterintuitive, expensive, and increasingly visible.
“This isn’t about too much wind”
Gordon Thomson spends much of his consultancy time working on renewable energy projects where grid constraints are not a footnote, but a defining factor. For him, the B6 issue is often misunderstood.
“Scotland isn’t short of renewable energy,” he notes. “If anything, we’ve delivered that part of the transition quickly. The real challenge is that the grid and flexible energy markets haven’t evolved at the same pace.”
That view is supported by independent analysis. In September 2024, UK energy think tank Regen published “Toxic constraint coverage could damage the Clean Power Plan” (Regen analysis, September 2024), highlighting that over £1.1bn in constraint costs had already been incurred that year. Crucially, Regen showed that only around 24% of those costs were linked to payments to curtailed renewable generators, while the majority were paid to fossil fuel generators instructed to run to maintain system balance.
As Regen argued, the problem is not “too much wind in the wrong place”, but a combination of historic underinvestment in transmission, reduced operational capacity on key boundaries like B6, and market mechanisms struggling to keep pace with a changing system.
It’s also worth recognising that this conversation has moved well beyond technical circles. Curtailment, constraint costs and boundary limitations have become highly visible and highly politicised topics, debated extensively across industry and public platforms alike.
Recent commentary and data visualisation from organisations such as Octopus Energy, alongside work by Robin Hawkes and Dale Vince, have brought unprecedented attention to where renewable energy is generated, where it is constrained, and how those costs are communicated to consumers.
Demand, delivery and the southern view
As an Electrical Project Manager working across offshore and onshore wind and emerging technologies, Charles Balderson approaches the same issue from the delivery and system-integration side of the equation. His work focuses on how energy moves through the system and what happens when it can’t.
From a project delivery perspective, Charles is clear:
“England holds the bulk of demand, Scotland holds a growing share of generation. The challenge is the infrastructure in between. If that boundary doesn’t work efficiently, everyone pays for it.”
For Charles, the B6 constraint shows up early in project feasibility, cost modelling, and programme risk. Decisions about where assets are built, how they connect, and when they deliver are inseparable from network capability. By the time a project reaches construction, those early assumptions are very hard, and very expensive, to undo.
What the B6 boundary really represents
The B6 boundary is not just a physical limitation. It is a timing issue.
Offshore wind deployment in Scotland has accelerated rapidly over the past decade. Transmission upgrades, by contrast, require long planning horizons, complex consenting, and significant construction effort. According to the most recent National Energy System Operator Electricity Ten Year Statement (ETYS), key Scottish boundaries have at times operated well below nominal capacity due to system conditions, maintenance, and operational constraints, amplifying constraint costs.
This mismatch creates the conditions for the “toxic constraint” narrative, a story that risks undermining public confidence in renewables by blaming generation for failures rooted in system coordination.
Where Vekta Group fits in
Between Gordon’s operational focus and Charles’ project delivery and electrical systems experience, the boundary issue is examined from both ends of the project lifecycle.
At Vekta Group, consultants work on projects where boundary constraints, curtailment risk, storage options, and grid reinforcement shape decisions from the outset.
Understanding how and where constraints arise is critical to advising clients realistically and to avoiding surprises later in the project lifecycle.
It’s also why Vekta Group invests time in system-level thinking and tools such as IAiN (Integrated Artificial Intelligence and Networking). By capturing assumptions, spatial constraints, and decision logic early, before projects lock into expensive paths, IAiN helps ensure that intelligence developed during consultancy work is not lost as projects scale or teams change.
Rivalry on the pitch, alignment in the office
On Saturday, Gordon and Charles will cheer for different teams. One may remind the other where the wind comes from. The other may point out where the lights stay on.
But when the final whistle blows, they’ll both be back working on the same challenge: making sure the UK’s energy system can move clean power to where it’s needed, efficiently and affordably.
The grid doesn’t care about rivalries. It responds to physics, planning, and foresight.
A Valentine’s Day reminder (same day as the Rugby, you can thank us later!)
If there’s a lesson to take into the weekend, it’s this: the energy transition only works when connection is maintained.
Scotland’s generation and England’s demand are not competing assets, they are complementary ones. The boundary between them needs investment, coordination, and intelligence, not blame. Like many areas of the energy transition, constraint costs are as much about how we explain system behaviour as they are about the engineering itself.
On the pitch, may the best team win. On the grid, we’re all on the same side.
Further Reading & References
Robin Hawkes / Octopus Energy (Live, 2024–2025): Renewables Map - Constraint & Curtailment Visualisation
An interactive, publicly available mapping project visualising renewable generation, curtailment and system constraints across Great Britain.
Regen (September 2024): “Toxic constraint coverage could damage the Clean Power Plan”
Regen analysis highlighting that only around 24% of UK constraint costs are linked to renewable curtailment, with the majority driven by system and market design issues rather than “too much wind”.
National Energy System Operator (NESO), formerly National Grid ESO (2024)
Electricity Ten Year Statement (ETYS): Provides detailed analysis of transmission boundary constraints, including B6, and outlines future network reinforcement requirements across Great Britain.
Apatura (2024): “The Scottish Boundary Bottleneck That’s Costing the UK £1bn a Year”
A clear overview of Scottish boundary constraints, curtailment, and the need for coordinated transmission investment.
Solar Power Portal (2024–2025): Coverage on battery energy storage as a faster, lower-cost way to manage grid constraints and reduce consumer costs while transmission upgrades are delivered.
Regen / Industry Commentary (2024–2025): Analysis on locational pricing, progressive market reform, and the risks of oversimplified narratives around renewable constraint costs.
Editor’s Note
The Calcutta Cup, contested annually between England and Scotland since 1879, is one of rugby’s oldest international trophies. Created by the former Calcutta Rugby Football Club, it has outlasted leagues, professionalism, and changing eras of the sport.
It still matters because the rivalry is real, the contest is settled on the pitch, and the tradition connects today’s game with its past.
Like the B6 boundary, it’s a reminder that long-standing lines endure but progress depends on how we work across them.