Rerouting power transmission through bottlenecks in the UK grid has allowed for greater freedom 1.5GW of capacity and save £380m. Andrew Wade reports.
Like most power networks around the world, the UK’s electricity grid was not built with renewables in mind. As the legacy nuclear plants and large-scale centralised thermal production from fossil fuels is phased out and more distributed and intermittent renewables come online, it poses challenges to transmission.
While major changes will be required in the next few years to adapt the network to these new challenges, solutions are already in place to reduce bottlenecks and increase the capacity of the existing network. One such solution is the winning entry in our Energy & Environment category.
Led by National Grid Electricity Transmission (NGET), ‘Working smarter to get to net zero’ has seen the rollout of the world’s first large-scale use of a modular power flow solution based on SSSC (Static synchronous series compensator) technology. The project saw the installation of Smart Wires’ SmartValve technology across five circuits at three National Grid substation sites in the north of England in 2021, releasing a total of 1.5GW extra capacity – enough to power one million homes in the UK. But the project’s roots go back several years, to when the potential bottlenecks in the grid were first identified.
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“NGET and Smart Wires collaborated on an NIA (Network Innovation Allowance) innovation project in 2017 to evaluate the potential of modular power flow control technology to be adopted on the GB transmission network,” explained Zac Richardson, director of New Infrastructure at NGET. “Following the NIA, power flow control devices were identified through internal studies as a solution for multiple projects aimed at resolving the bottlenecks.”
SmartValve is an intelligent power electronics device that intelligently redirects power to lines with spare capacity. This pulls electricity from overstretched and underutilised lines, optimising the grid, and optimizing the grid. There have been 48 SmartValves installed in total across five circuits at three National Grid substations, Penwortham, Harker, and Saltholme. These substations are critical junctions for the transmission power, as more of the country’s renewable energy is sent south to densely populated regions.
“The modular nature of the technology means that SmartValve deployments can vary in terms of layout and footprint, depending on the specific needs of the network where it is located,” said Richardson. “These deployments typically have a smaller footprint than alternative power flow control technologies, and the deployment design can be adapted to fit the available space at the site.
“For example, double stacking the SmartValves to reduce the overall footprint or using a non-conventional layout to fit in a uniquely shaped space. SmartValves can be easily added to existing deployments and installed devices can be moved between sites depending on the capability required on a circuit at any point in time.”
This modularity was very helpful to the team during the rollout. NGET was able move equipment between Penwortham’s two circuits, solving the problem with the existing equipment and maintaining optimal power flow.
“Modular solutions such as SmartValve enable NGET to adapt the solution as the network needs change over time, scaling up or down the deployment or relocating it to another area of the network,” said Richardson.
“The SmartValve installations at Penwortham were initially designed to account for power flows in the Mersey region with the power station generating. These conditions led to circuit loads from Penwortham into the region being unevenly loaded. This resulted in two different capacities SmartValves. Closure of the power station means the circuit loadings are now equal and so the SmartValve installations will be modified to account for this change.”
The ability to redeploy the technology helped foster closer collaboration between project partners. They were flexible and able to adapt to changing requirements. SmartWires had been working with NGET from early in the project’s lifecycle, supporting the detailed technical studies as well as analysing the impact of using power flow control technology at scale on the transmission system.
NGET has been controlling the devices using its SCADA system (Supervisory Control & Data Acquisition), since installation. This allows SmartValves to be managed at each substation from its Berkshire control room. Richardson explained that the SmartValve system will be programmed to operate autonomously based upon the local conditions in the surrounding network.
“The SmartValve is designed to ensure the control room operator always has the ability to adjust the operation to meet the system conditions in real time,” he said. “This can be done through a combination of pre-programmed current management set points and through instruction based on the wider network. It was designed like this to fit within existing planning processes with the ability to adapt and increase overall automation tools as the control room adapts and changes to the environment.”
As well as freeing up 1.5GW capacity, the project has also delivered an estimated cost saving of £380m. This is due to a reduction of constraint costs, which arise when generation must be curtailed to maintain grid limits.
“When the system has bottlenecks due to limited network capability, the system operator needs to constrain generation so that flows are within the capability of the network,” Richardson explained. “The £380m reflects the reduction in constraint costs for consumers due to the additional network capacity provided by the SmartValve installations.”
Given these successes, it’s no surprise that NGET has further installations in the works, with additional SmartValve devices set to be come online across the grid in 2022.
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