As system inertia reduces with the decarbonisation of the GB energy landscape, the cost of frequency containment services is expected to significantly increase. Currently, ancillary services for frequency containment are procured through separate auctions and tenders, decoupled from the energy market, and not considering detailed time dependencies. This project will develop a novel prototype software tool for achieving co-optimisation of energy and frequency control services, integrating the mathematical models previously investigated within Imperial College London's research activities. This software tool will explicitly link the technical and temporal characteristics of the different services with the aim to operate the national electricity grid more cost effectively. Currently, no system operator in the world fully co-optimises different frequency-containment services, this project will develop a world-first tool to achieve this.
Benefits
The cost of ancillary services for frequency control is projected to increase significantly by 2030, up to an estimated £1bn/year in GB as modelled by Imperial College London. Achieving co-optimisation of energy and different types of frequency-containment services could achieve significant savings by considering the temporal links of all available services and reducing the need to use fossil fuel plants for maintaining frequency stability. This tool would enable the ESO to find optimal volumes needed in Dynamic Containment auctions, as well as open the potential for intra-day auctions for frequency response services. Considering this, additional benefits include increased system reliability and contributions towards net-zero targets.
Learnings
Outcomes
The project outcomes so far include major enhancements to the Co-optimisation tool this includes:
- Over 500 generators with comprehensive Unit commitment parameters (e.g., MNZT (Minimum Non-Zero Time), MZT (Minimum Zero Time), etc.) have been incorporated into the co-optimisation model.
- All frequency-related constraints have been included in the tool for co-optimisation of Energy and Frequency (COEF) - Rate-of-Change-of-Frequency (RoCoF), Frequency Nadir, and quasi-steady-state requirements.
- Frequency services related to inertia, primary frequency response (PFR), dynamic containment (DC), the influence of dynamic regulation (DR), dynamic moderation (DM), and the optimised largest power infeed/outfeed are involved in the co-optimisation model.
- The interconnectors power flows (power import and export) are optimised in the model to minimize the whole-system costs are included to model the largest power infeed or outfeed, depending on its status of power import and export.
- The model is now capable of capturing the influence of demand-side inertia.
- Requirements for both Low and High Frequency Security have been included in the COEF model.
- Operating reserve requirements have been included in the COEF model.
- Work on incorporation transmission network constraints and line outages in the COEF model has started.
- The influence of considering frequency-related constraints on operation cost and computing time is analysed. Under most cases, the computing time can be limited within 15 minutes.
- The influence of minimum inertia limit is studied.
Lessons Learnt
Initial analysis has demonstrated significant benefits of coordinating frequency regulation services and energy delivery, while considering changes in system inertia. Detailed analysis of the potential benefits is planned in the upcoming work packages. A full list of lessons learnt will be published when the project is completed.