A Zero Carbon Energy System: The Operability Challenge

The UK energy sector has been invigorated by the recent commitments to reach Net Zero carbon emissions by 2050 (2045 in Scotland), and a fully decarbonised electricity system by 2035. Meeting these legally-binding emissions targets will require a comprehensive rethink of how the UK power system – a central enabler of the transition to Net Zero – is developed and operated.

While work is underway to facilitate the near-term replacement of fossil-fuelled generation with renewable technologies, less attention is given to the end state – the operation of a fully decarbonised power system.

This report – created in collaboration with the Faraday Institution and supported by TNEI – presents fresh thinking about a zero carbon system and how it will be operated. It focusses on some of the key parameters that make up the system operation, and is intended as a starting point to generate conversation and debate.

Key findings

  • In a net zero power system, flexible demand could be shifted to meet available renewable generation, rather than dispatching generation to meet demand. Today demand is mostly predictable, and generation is dispatched to meet it. In a net zero system, generation and demand will be more weather dependent and there will be new opportunities for flexible demand, e.g. battery and EV charging, heat pumps and hydrogen production, to be dispatched to use renewable generation when it is available.
  • A net zero system will no longer have access to bulk stored energy in the form of fossil fuels and security of supply will need to be achieved by alternative sources. Consumers will become more dependent on their electricity supply due to increased electrification and demand will become more weather dependent. Securing supply during periods of high demand and low renewable output, e.g. a cold winter, will require new forms of storage spanning months and years.
  • Digitalisation and enhanced data will provide an opportunity to use dynamic approaches to operability and move away from deterministic rules. Today a set of deterministic rules are used for system operation. Increasing data collection and using more sophisticated tools will provide the opportunity to use dynamic operability parameters in real time, e.g. dynamic assessment of the risk of network faults.
  • Devices like Electric Vehicle (EV) chargers and heat pumps could support system operation by automatically and autonomously responding to frequency and voltage. Net zero system operation can be supported by devices, such as EV chargers and heat pumps, by enabling them to respond to frequency and voltage signals. This would facilitate an automated response without the need of central control.
  • Growth in renewable, asynchronous generation brings the opportunity to reconsider the approaches and parameters used in system operation. Today system services are being used to replace the dynamic behaviours synchronous generators provide. A net zero system provides an opportunity to reconsider the technical parameters considered within system operation, e.g. the relaxation of frequency standards.
  • The technological and societal changes that come with net zero present opportunities for different standards and approaches to operability. System operation is a product of the physical characteristics of the network, what is connected to it and the standards expected from it, e.g. security of supply. Societal, technological and political choices will interact with each other and influence how the system is operated.
  • There will be many possible roles for energy storage in a net zero system. The cost will depend on several interacting technical factors including size, duration and how often it is used. Storage costs will depend on technological characteristics, like whether costs scale with power (MW) capacity or energy (MWh) capacity, and roundtrip efficiencies. How the storage is used, and how often it “cycles” will be very important in determining its levelised costs. Storage that cycles very infrequently might cost £1,000s or even £10,000s per MWh.
  • Further research would be valuable in stress testing the system, understanding the economics of flexible demand, investigating net zero energy markets, and exploring the requirements for and cost of storage in a net zero system. Research and innovation are ongoing across the whole energy sector, which will contribute to reaching net zero. Further suggested research includes:
    • “Stress testing” the system against extreme events, e.g. long periods of low wind.
    • Interactions between weather and energy demand and the impact on demand flexibility from heat and transport.
    • The economics of demand side flexibility to support investment, policy, operational decisions and impact on customers’ comfort and wellbeing.
    • Net zero electricity system and alignment of electricity markets.
    • The requirements for, and cost of, storage within a net-zero system.

Read the report

A Zero Carbon Energy System: The Operability Challenge

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