UKPN opens DERMS access to IDNO customers

UK Power Networks has extended access to its Distributed Energy Resources Management System to customers connected through independent distribution network operators, widening the use of flexible connections beyond sites attached directly to its own distribution network.

The change allows eligible demand and generation customers on IDNO networks to connect where conventional reinforcement would otherwise increase cost or delay delivery. Participating sites accept operating limits that can vary when local network conditions require it, allowing available capacity to be used while the distribution system remains within its electrical limits.

GRIDSERVE’s electric vehicle charging hub at Extra Motorway Services in Cobham, connected through ESP Utilities Group, is the first fully flexible demand customer using the IDNO route. The project demonstrates that DERMS can manage large electricity consumers as well as generators such as solar farms and other distributed energy resources.

The development matters because high capacity demand connections are becoming a larger part of distribution planning. Ultra-rapid charging hubs, commercial heating, industrial electrification and other large electrical loads can require substantial capacity at individual connection points, even where the surrounding network is heavily loaded only for limited periods.

A conventional firm connection is generally designed so that the requested capacity remains available without the customer having to respond to local constraints. Where the network cannot accommodate that requirement, additional cable, transformer or upstream reinforcement may have to be completed before the connection can operate at full capacity.

A flexible connection provides another option. DERMS monitors network conditions and manages participating assets according to agreed limits, allowing a customer to connect earlier if it can tolerate periods in which its import or export capability is reduced. The approach does not create new physical capacity, but it can make better use of existing equipment where the underlying constraint is intermittent rather than continuous.

For a charging hub, the trade-off can be commercially significant. A motorway site may reach very high demand when several vehicles use high power chargers simultaneously, while drawing considerably less electricity during quieter periods. Building the connection entirely around maximum theoretical demand can require reinforcement for conditions that occur for only part of the operating day.

Flexible access allows that demand profile to be managed against the actual capability of the network. If the distribution system approaches an agreed limit, the participating connection can be instructed to reduce consumption. When the constraint clears, more capacity becomes available again.

The engineering becomes more complicated when the customer sits behind an IDNO network. Independent distribution operators own and operate networks that connect into the host distribution system, so the controllable asset is separated from UK Power Networks by another network boundary.

That requires coordination between the host operator, the IDNO and the customer. Communications, control interfaces and protection arrangements have to ensure that an instruction generated from conditions on the UK Power Networks system reaches the relevant demand or generation equipment reliably.

The Cobham deployment therefore tests more than the ability to curtail an EV charging load. It establishes an operating route through which flexible connection arrangements can function across the boundary between a distribution network operator and an embedded independent network.

ESP Utilities Group said the arrangement should enable future customers to reduce reinforcement requirements and accelerate project delivery. GRIDSERVE has similarly linked flexible access to its ability to bring additional high power charging infrastructure online without waiting for every underlying network upgrade to be completed.

That does not remove the need for reinforcement altogether. If demand grows to the point where restrictions would occur too frequently, or if the connection requires firm capacity for operational reasons, new physical infrastructure can still become necessary. Flexible access changes the timing and utilisation of investment rather than replacing cables and transformers indefinitely.

The model also increases reliance on communications and control systems. A conventional firm connection is governed largely by the rating and protection of physical assets. A DERMS connection adds measurement, automated control and customer equipment to that chain, making availability, communications integrity and fail-safe behaviour part of the connection design.

Those digital requirements become more important as distribution systems accommodate a growing range of controllable assets. Batteries, charging sites, renewable generators and industrial loads can all change power rapidly, giving network operators more flexibility but also increasing the amount of data and control needed to manage them safely.

UK Power Networks has already used flexible connections for distributed generation and demand directly connected to its network. Opening the same approach to IDNO customers removes a structural boundary that could otherwise leave projects unable to access flexible capacity simply because the final section of their network is independently owned.

The practical value will now depend on how consistently the model works across different IDNOs, connection sizes and local constraints. Cobham provides the first operating demand example, but wider adoption will test whether the technical interfaces can be standardised sufficiently to avoid recreating a bespoke engineering exercise for every connection.

For developers, the attraction is straightforward: a flexible connection can separate the date a project begins operating from the later date when every surrounding network constraint has been permanently reinforced. For the network operator, the advantage comes only if that earlier connection remains controllable when the system actually becomes constrained.

The opening of DERMS to IDNO customers therefore expands the role of active network management in the connection process. As electrification adds larger and more variable loads, the distinction between building additional capacity and managing existing capacity more intelligently is becoming an increasingly important part of distribution engineering.