National Grid ESO (NGESO) has outlined its plans to solve challenges in the delivering of a zero-carbon electricity network in 2025.
Its latest Operability Strategy Report outlines how it is working with a range of stakeholders to improve various aspects such as systems, markets, policy, technology and innovation. All need to be expanded to help enable NGESO to achieve a net zero energy system by 2035.
One of the most pressing issues with the system is the introduction of new technologies, and this will continue to be a key area for innovation as the UK ramps up the target of operating a zero-carbon system in the mid- 2030’s.
NGESO stated that by 2025, the minimum inertia that the system can operate at will be around 102GVAs assuming a need to secure against a highest loss of 18000MW and keep the rate of change of frequency (RoCoF) within 0.5Hz/s. This currently is being operated at a minimum of 140GVAs and thus NGESO is currently at the start of reducing operational limits to meet the zero carbon targets.
Alongside inertia, NGESO has stated that the future procurement of stability services will be to ensure economic system operation and it is working to ensure that policy on managing low fault infeed levels are fit for purpose in the future system.
For a compliant network in 2025, 2200MVAr (megavolt ampere of reactive power) of new capability will be needed to economically maintain the network. To help enable this, the UK must maintain voltage levels across the transmission network within the Security and Quality of Supply Standards to ensure safety and reliability of the network.
Despite this, voltage management continues to be a challenge, NGESO said, as reactive power demand on distribution networks continue to decrease and power flows across the transmission network reduce.
These system changes are said to be driving an increasing need to absorb reactive power on the transmission system and that less dispatchable generation is reducing available reactive power capacity in the right regions.
NGESO stated it is exploring options to access new sources of reactive power, reduce voltage costs in the short term and is planning on setting long term future reactive needs.
Crucially, the report indicated that the UK will be a net annual exporter of electricity by 2030 further showcasing the surging growth being witnessed in the industry. However, this growth continues to drive a need for more network capacity to allow new projects and technologies to be connected.
To this end, NGESO is said to be mitigating rising constraint costs, contributing to network planning reviews and supporting the connection of new generation technologies.
A newly passed Electricity System Restoration Standard included several key reliability demands. The most prominent of these was that 100% of national demand must be restored within five days in the event of a power outage – 60% of regional demand must also be restored within 24 hours.
To allow this, NGESO is exploring the use of various technologies such as solar, wind and hydro as a means to provide restoration services and also reduce the carbon footprint of these services.
Alongside the development of a reliable network, NGESO’s report also outlined several areas to explore in regard to balancing the system. This included frequency, within-day flexibility and adequacy.
By 2025, the report stated that there will be a maximum requirement of 2500MW for balancing reserve by 2050. However, the influx of new technologies such as EVs and also interconnectors has brought challenging conditions for NGESO.
To solve this, new services such as balancing reserve and static recovery are set to play a vital role in managing these challenges on the new system.