National Grid ESO - glowlines in a field

What are we doing to manage congestion on Britain’s electricity network?

Our job is to balance the electricity system 24 hours a day, 365 days a year, making sure homes and businesses have the power they need whenever it’s needed.

To do that we keep Britain’s electricity flowing safely, reliably and efficiently around the country’s transmission lines.

As with any aspect of operating the electricity system, there are challenges involved in moving megawatts from one place to another.

One of our key challenges is the physical limit to the amount of power that can be transmitted through any piece of equipment.

That limit is set for safety reasons, to make sure that equipment doesn’t overheat or become overloaded.

“Our Network Options Assessment identifies the network reinforcements needed in the coming years to manage constraints – but we’re already working with industry on solutions to address the challenge”

If a piece of equipment is reaching that safe capacity to carry energy, it can act like a bottleneck – we call it a ‘constraint’ – and we’ll need to take action.

It could happen, for example, if a high volume of wind power being generated in the north is trying to meet demand in the south of the country.

The transmission system needs to be capable of handling the high flow throughout the route that power would take across the country – but in some cases it might meet a constraint.

Find out more about our constraint management pathfinder

To alleviate any congested parts of the network, we might pay generators to vary their output and optimise the flow of electricity in that area of the grid.

The cost of these constraint payments is continually weighed up against the cost of building new infrastructure, to ensure we keep the costs of running the system as low as possible. To date, these constraint payments have been the most cost-effective option to operate the electricity system securely.

Working together to manage constraints

Over the coming years, as more onshore and offshore zero carbon generation connects to the system in the north and east of Britain, constraint costs (particularly for the movement of power from north to south) are likely to increase.

Our recently published Network Options Assessment (NOA) identifies the network reinforcements that would be needed in the future to manage major constraint boundaries – but we’re already working together with industry on solutions to address the challenge.

“We’re committed to working closely with industry to explore and develop options for managing constraints in the most effective way possible”

We’re exploring ways we can start to introduce new mechanisms, markets or approaches that aim to reduce the congestion costs ahead of the new boundary reinforcements.

One of the ways we’re doing this is through our constraint management pathfinder – one of a suite of pathfinder projects aiming to address key electricity system challenges.

The constraint management pathfinder is collaborating with industry on solutions to reduce the impact of network constraints, minimise actions to reduce renewable generation and lower costs for the end consumer.

We’re also engaging with stakeholders on ideas such as enhanced BSUoS forecasting; commercial intertrip schemes; commercial models for storage in a heavily constrained network; regional flexibility markets for embedded generation; and working with transmission owners to enhance the capability of existing assets.

Our plans are evolving, but we’re committed to working closely with colleagues across the energy industry to explore and develop options for managing constraints in the most effective way possible – both now and in the future.

If you’d like to engage with us around our constraints management activity, get in touch at [email protected]