Britain’s grid operator forecasts about £4 billion in costs from transmission bottlenecks in 2027. That raises a practical question for Bitcoin mining’s flexible-power pitch: can miners cut costs by using Scottish wind that cannot reach other consumers?
The National Energy System Operator (NESO) published the forecast on Nov. 12. Its latest cost breakdown shows why the answer depends on where a mine connects and which costs it actually avoids.
Thermal constraints occur when transmission lines cannot safely carry all the available electricity. NESO may then pay generators to reduce output while securing replacement supply elsewhere.
The forecast covers thermal constraints, not all electricity balancing costs. It is sensitive to gas prices and network availability. NESO estimates costs would be 16% lower without network outages, although those outages also allow reinforcement work intended to ease future bottlenecks.
In its Nov. 9 outturn explanation, NESO reported total balancing costs of about £3 billion for 2025/26, including roughly £2 billion for thermal constraints. Just under £500 million was paid to wind farms to reduce output.
About 75% of thermal constraint costs went toward replacement energy, predominantly from gas units.
Scotland nevertheless offers a potential use case. NESO says 28% of wind in the northern area above a transmission boundary known as B6 was curtailed in 2025/26, compared with 13% across Great Britain.
A flexible mine could reduce wind turn-down costs by using electricity that would otherwise be curtailed, at a connection and time that helps manage the relevant bottleneck. But adding demand in the north does not itself deliver more power to the south. As long as the boundary remains binding and southern demand is unchanged, replacement supply is still needed there.
That limits the savings claim: reducing wind turn-down does not prove there would be an equivalent reduction in gas generation, consumer bills or emissions.
Using wasted wind needs a business case
The Cambridge Centre for Alternative Finance’s mining survey offers evidence that miners can adjust their consumption. Respondents reported curtailing 888 GWh of electrical load during 2023. That measures demand turned down. Using surplus Scottish wind, however, would require demand to turn up at the right place and time.
The survey covered 49 firms representing 48% of Bitcoin’s network hashrate at the time of data collection, with activity concentrated in North America. It does not establish that intermittent mining in Britain would be profitable. Electricity accounted for more than 80% of surveyed miners’ cash-based operating expenses.
NESO’s November thermal constraints report identifies additional flexible demand in constrained areas as a way to mitigate the problem. Its March 5 proposed Demand for Constraints design focused on Scottish boundaries. It envisaged registration and dispatch through the Balancing Mechanism, NESO’s system for directing electricity supply and demand in real time, with options for both new connections and existing assets providing additional flexible demand. The March design proposed service deliveries from 2028, after the year covered by the forecast. It did not establish approval or payment eligibility specifically for Bitcoin.
For a mine, a usable connection, qualification to provide the service and enough operating hours to cover costs would all matter. For consumers, the relevant comparison is the expense actually avoided after accounting for costs added by the project.
NESO’s test is overall system cost. The roughly £4 billion forecast indicates the scale of a grid problem, but does not price a mining solution.
