Hassan Wajahat Qazi

Harnessing Flexibility from Hot and Cold

As has been often reported, electricity systems with high levels of variable wind and solar power generation would benefit from demand flexibility. What is not as often mentioned is that electrification of the transport and heat sectors could exacerbate the need for flexibility, if they are implemented as inflexible loads. This demand could also be made more flexible, but it comes with a cost. The main issue is to identify the cases in which the benefits will outweigh those costs, a matter that will naturally depend on the evolution of specific energy systems. In this article, we lay out some generic principles and characteristics related to heatsector flexibility and demonstrate its possibilities using specific examples. While we generally use the word heat here, most of the discussions also apply to cool, which, after all, is just another form of temperature difference.

Impact of electric vehicle load response variation on frequency stability

Electric vehicle (EV) load in future power systems is likely to increase due to decarbonisation of the transport fleet. EV load can be utilised to provide primary frequency reserve (PFR), provided its variability with respect to system requirements is taken into consideration. EV based PFR can in certain cases negatively impact system frequency stability. Better estimation of EV reserve and consideration of its volume and responsiveness, relative to system PFR requirements, therefore becomes important. This paper presents a model for EV load estimation, and proposes control mechanisms which cater for available EV reserve variability and system requirements. The results show that the proposed control mechanisms are robust and ensure frequency stability, with negligible impact on the speed of response and hence the frequency nadirs.

Provision of flexibility at high wind penetration levels using modern storage heater load

Modern storage heaters can facilitate higher levels of wind generation on the system by mitigating the effects of wind variability and uncertainty. This paper presents a coordinated control strategy for modern storage heater load to reduce conventional plant ramping and cycling requirements. Control practices and mechanisms required to utilise storage heater load for reducing system net load variability have been presented. The communication update rate to the heaters has been shown to impact conformance to the control objective. Acknowledging the impracticality of individual appliance control, a clustering scheme has been proposed to reduce the overall communication requirements. Heater load shaping mechanisms have also been presented to provide real-time system ancillary services at high wind penetration levels.

Impact of large scale demand side response on system frequency- A case study

Demand side response (DSR) has gained significant interest due to the time-varying and uncertain nature of renewable energy, and the challenges associated with integrating renewable technologies into power systems. DSR is considered as a fundamental component of the emerging smart grid paradigm and is seen as a potential means to achieve higher renewable targets across the globe. It is, therefore, imperative to explore the potential implications of wide-scale DSR on system operation. In particular, the impact of large-scale coordinated load switching on potential operational limits, while considering different DSR-based magnitudes and ramp rates, is considered here. The All Ireland System (AIS) projected for the year 2020, and characterised by a significant penetration of wind power has been used as a test system in the presented research study.