How operators of the UK’s T&D assets are prioritising the connection of energy storage, bringing much-needed flexibility to the grid. today.
Battery energy storage systems (BESS) are a unique form of asset within the transmission and distribution, or ‘T&D’, system. Capable of absorbing electricity when supply exceeds generation, and exporting power to the grid during times of peak demand, BESS deliver flexibility — something that power generation plants, whether wind, solar, nuclear or gas, are not designed to do.
Owners of T&D infrastructure have recognised this differentiated functionality and, as such, have started ensuring that connections for energy storage projects — whether standalone or co-located with a renewable power plant (hybrid) — occur more quickly.
Read on to learn more about the ways in which BESS connection backlogs are being reduced
Accelerating the connection of 20 GW of clean energy projects
As part of wider changes to Great Britain’s connections regime, namely the reformed ‘First Ready, First Connected’ (TMO4+) process, National Grid has taken steps this year to accelerate the connection of up to 20GW of clean energy projects to its T&D networks in England and Wales.
On its transmission network, 19 battery energy storage projects, totalling around 10GW, are being offered dates to connect, averaging four years earlier than original agreements.
This has been made possible by removing the need for non-essential engineering works prior to connecting energy storage.
The new policy is led by National Grid Electricity System Operator (ESO), which operates the grid and connects projects, in partnership with National Grid Electricity Transmission (ET), which builds the transmission infrastructure in England and Wales.
The approach to transmission energy storage connections forms part of the ESO’s five-point plan to speed up connections. Meanwhile, National Grid ET is undertaking a review of projects in the connections pipeline in England and Wales to identify which can come forward, based on new planning assumptions agreed with the ESO.
Traditionally, National Grid carries out network reinforcements before a project connects, which can add years to the process. Reinforcements used to be based on the assumption that batteries could charge at peak times and export when generation is high, exacerbating system peaks and constraints.
Accommodating battery energy storage systems
National Grid will now offer selected battery projects a transmission connection before network reinforcements are made, on the proviso that the ESO can adjust the battery’s operation where necessary to reduce system impact.
A further batch of clean energy projects, comprising mainly standalone batteries — but also some projects where batteries are co-located with solar or wind — will be offered accelerated transmission connections through to the end of 2024, potentially bringing forward another 10GW.
In addition, a second expression of interest is being rolled out to the next group of customers. Coupled with plans to replace the ‘First Come, First Served’ distribution connections process with the more responsive and accommodating ‘First Ready, First Connected’ approach, the second wave will allow even more low-carbon projects to connect faster, according to National Grid.
Other promising grid connection developments
Distribution system operator (DSO) UK Power Networks, which serves customers in London and the south-east of England, has introduced a ‘fast-track’ scheme to “take years off” connection time frames for projects that were initially told they would have to wait up to a decade or longer.
The scheme will initially benefit 25 projects, amounting to 836MW, set to connect as soon as they can enter construction. The fast-track scheme was developed by UK Power Networks in collaboration with National Grid ESO and other distribution networks.
These 25 projects include a 98MW solar farm in eastern England and a 100MW hybrid solar-battery storage site in the south-east.
These are among 14 projects in eastern England totalling 465MW and a further 11 schemes in Kent, Surrey, and Sussex, totalling 371MW. According to the DSO, the 836MW of new generation equates to a fifth of the peak demand of the London distribution network.
Using data & insights to free up capacity
To enable this first phase in a series of capacity releases, expected to create multiple gigawatts of capacity for generation projects in 2024, is a new process led by UK Power Networks called Technical Limits. This process uses insights and data developed by the DSO’s distributed energy resource management (DERMS) platform.
Nationally, network operators have been working with customers to address challenges to securing new connections, as a result of constraints on the national transmission system.
Supporting developers in selecting suitable BESS sites
In a separate initiative, UK Power Networks has produced an Advanced Curtailment Report to help developers and customers make more informed decisions about how and where to locate new energy assets, like solar, wind and battery storage.
The analysis aims to get more renewable energy and flexibility capacity onto the network quickly, and at a lower cost. The development of this service involved extensive consultations with customers, including a joint consultation with fellow distribution network operator, National Grid Electricity Distribution.
From May 2024, all customers receiving a flexible connection quote will automatically be given an Advanced Curtailment Report, which provides a breakdown of curtailment for each of the different network constraints which could impact their site, and how much impact their potential asset could have on each of the each of the network assets.
The report will also provide more information about the other sites ahead of them in the connection queue, including:
- Capacity, technology, and application date
- Ratings of the constraint linked to the site
- Detailed, half-hourly data on exactly when and by how much the site is forecasted to be curtailed.
The latest BESS developments
To keep up with the latest advancements in battery energy storage systems — and wider renewable energy developments— be sure to follow our News page.
In the meantime, if you have any questions about the emerging technologies and changes discussed above, get in touch with our experts.
