Assessment of the value of flexibility by using stochastic scheduling tool

Abstract

This thesis proposes novel analytical models for assessing the role and the value of various flexibility resources in the future low-carbon systems with high penetration of renewable energy resources. A novel stochastic scheduling model is developed, which optimises system operation by simultaneously scheduling energy production, standing/spinning reserves and inertia-dependent frequency regulation in light of uncertainties associated with wind energy production and thermal generation outages. The proposed model is shown to be particularly suitable for analysing the value of flexibility. Following this, the thesis presents an assessment of the value that energy storage may deliver to the owner in the application to energy and ancillary service markets. The results suggest that the value of energy storage is mainly driven by the temporal arbitrage opportunities created by volatility in energy prices. The value of energy storage is shown to be site-specific when there are active network constraints. A novel methodology is then proposed and applied to assess the role and the value of frequency regulation support (synthetic inertia (SI) and primary frequency response (PRF)) from wind plants (WPs). The results suggest the SI could effectively reduce the system operation cost in the system, especially with high penetration of wind generation. The analysis also demonstrates the value for WPs in providing PFR is system-specified. Combined provision of SI and PFR is required, in the case that there exists severe recovery effect associated with SI provision. This thesis also proposes a novel demand side response model (DSRM), which models and controls the recovery period during and after frequency regulation provision and thus optimally allocates multiple frequency services. The results attest the value of the DSRM compared with alternative approaches for demand response schemes. Moreover, this thesis quantifies the implications of electric vehicle deployment, heat pumps, industrial and commercial and dynamic time-of-use tariffs for the carbon emissions and renewable integration cost of the broader GB electricity system. Finally, this thesis investigates the value of enhanced flexibility from conventional plants. It has been shown that the value increases with penetration of RES; however, different systems may require different types of enhanced flexibility features. Moreover, different system scheduling methods, risk attitudes, frequency response requirements and carbon prices could significantly change the value of flexibility.