Based on government targets, the UK power system is to be fully decarbonized by 2035, meaning that subject to security of supply, the UK will be fully powered by green electricity.
Planning for the achievement of this ambitious target presents the collective of UK power grids (transmission and distribution) with perhaps its biggest challenges yet. The following three are among the most important:
Timely delivery of network capacity
Large volumes of variable renewable generation capacity connecting into the system require unparalleled investment to expand and reinforce the electricity transmission system. However, there is uncertainty around precisely how much will be needed, where, and when. This inhibits networks’ ability to plan and secure regulatory funding for investment, which in turn creates further uncertainty with developers and investors. Even where investment requirements have been clearly discovered, the scale and pace are unprecedented and at risk due to staffing and skills gaps, stretched global supply chains for essential materials, lack of timely network access, and the parallel need for facilitative information and operational technology (IT and OT) investments.
Different parts of this puzzle are being considered in a suite of reform programmes around network connections, network planning, and network design. Ofgem’s introduction of the ASTI (accelerated strategic transmission investment) regime in autumn 2023 should speed up the delivery of major power grid projects, but its efficacy remains to be seen. There is currently no centralized plan for the collective decommissioning of gas networks and transition to hydrogen.
Summer 2024 will see the introduction of the National Energy System Operator (NESO) and Regional Energy Strategic Planners tasked with optimizing infrastructure for molecules and electrons, at national and regional level. The governance framework and detailed decision-making methodologies for the NESO and affiliated entities are in development and have the potential to make or break the role of networks in realizing the UK’s decarbonization commitments.
The challenge also extends to the development and deployment of the grid network being lengthened to offshore wind projects around the UK. Without an offshore grid solution, the generation planned around the UK territorial waters would be relying on multiple single routes to connect to the onshore system, which is unrealistic to deliver in the timescales required by 2035 and less efficient than a more co-ordinated approach. Work has commenced, and will continue to be developed in addressing high-capacity routes to onshore landing areas, coupled with offshore hubs to accommodate the generation output from offshore wind farms. Development of hybrid interconnectors will also allow alternative access points for generation which, to date, has not been facilitated.
The role of hydrogen in maintaining grid resilience
In today’s power system, variability is primarily dictated by power demand. In 2050, variability will be far greater and driven not only by demand but also by variable renewable energy sources: most power will be generated through wind and solar, with nuclear still providing base load, and with dispatchable power and interconnectors supplying the remainder of demand.
The resilience of the grid, i.e. its ability to accommodate large sudden load swings and sustained periods of low wind, will be critically reliant on dispatchable generation. As we strive towards Net Zero 2050, an increasingly significant part of this dispatchable power will need to come from hydrogen-fired peaking plants. This requires urgent planning of, and significant investment in, hydrogen production, transport, and storage infrastructure alongside supporting infrastructure for CCUS and water, which will ensure hydrogen can play the part it needs to. Investment in ramping up the role of hydrogen must be carefully planned and delivered alongside a gradual easing off of natural gas and an increasingly electrified energy system. This will help ensure an economic, safe, and secure transition. The newly created NESO will have a key role in planning and overseeing this process.
NESO is looking ahead already, to deliver the Strategic Spatial Energy Plan (SSEP) – covering both electricity and hydrogen/gas in terms of the supply, demand, and co-optimised high-level network requirements. This will dovetail into both the Centralised Strategic Network Planning (CSNP) and Regional Energy Strategic Planning (RESP), covering onshore and offshore transmission networks along with the local energy plans alignment in the national plan.
Complexity of system operation
The increase in variable power supply and demand, as well as the growth and change in network users and technologies, create increasingly complex bi-directional power flows, stability issues, and different demand patterns. To manage these complexities, the energy system needs to operate faster and smarter, prompting the urgent need for investment in IT and OT to enable digitalization of network assets and system operation.
Electricity and gas networks will need to be self-healing and resilient to respond to an increasing variety of circumstances (e.g. bi-directional power flows, unplanned outages, severe climate events, cybersecurity events) in real-time. This will require autonomous and complex analysis of information to be presented to control room operators, so they are able to take the right actions. Network assets and low-carbon assets will need to be capable of collecting, sharing, and processing data to both inform and execute commands, leveraging international communication protocols. This means a full-scale upgrade of our energy networks for the latest Supervisory Control And Data Acquisition, (SCADA) systems with advanced control capabilities, digital asset instrumentation, advanced metering infrastructure (AMI), smart sensors and monitors.
A full-scale system upgrade requires network-wide planning and coordination within individual networks (to synchronize with capacity investments), between transmission and distribution systems, and again between electricity and gas grids. This full-system approach is essential to deliver system-wide resilience and restoration capability while ensuring it is delivered in time and economically. Software compatibility, standards for data exchange, and interoperability are critical requirements, and skills and supply-chain limitations are the primary showstoppers in the short to medium term.
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