Unlock the Flexibility of Combined Heat and Power for Frequency Response by Coordinative Control With Batteries

Abstract

Owners of combined heat and power (CHP), e.g., industrial manufacturers, are motivated to provide frequency response to power grids due to clear financial benefits. Yet, the slow response speed of CHP limits its capability in providing such services. Moreover, frequent adjustments would cause a faster lifetime reduction of CHP and rapid pressure fluctuation in the gas network. To further unlock the flexibility of CHP, this paper integrates a battery unit with CHP via a power electronic interface. A filter-based coordinative controller is designed for smoothing short-term fluctuations in CHP outputs. Based on the filter parameters and frequency response requirements, the minimum required capacity of the battery is identified. The results show that the proposed system enhances the capability of CHP for frequency response and mitigates the associated adverse effects on the gas network. The required capacity of the battery is economically feasible considering the benefit it brings to the CHP.

Fast frequency response provision from commercial demand response, from scheduling to stability in power systems

“…The impact of the implemented control strategy in regard to fast responding FFR units is not considered within the scheduling and dispatch process, and similarly, "static", "droop" and "hybrid" scenarios are not differentiated within the Backbone model as sources of reserve. The impact of FFR from supermarket refrigeration systems on the average RoCoF (over 500 ms) is reported as "actual RoCoF" (same as RoCoF roll in Section 2.3) in Table 3, based on the loss of the largest single infeed, and has been calculated using SBFM's output according to Equation (20). Table 3 illustrates the mediocre (average), the best, and the worst values for considered metrics.…”

“…The potential use of bitumen tanks, being representative of industrial heating loads, to provide EFR in the GB power system has been investigated, with a high level of satisfaction [19], where the required EFR response was provided by changing the temperature set-points of the bitumen tanks. It has also been demonstrated that battery energy storage systems can be deployed on industrial manufacturing sites, equipped with combined heat and power units, to unlock their potential to provide a firm frequency response (<10 s) [20]. The ability of commercial refrigeration systems to provide FFR services in the Irish power system has also highlighted the benefits of a suitably fast control strategy [21].…”

“…A demandside frequency control module has been added, with the frequency dependent reserve response based on three distinct methodologies, outlined later in Section 3.2. Using the single bus model, the rate of change of frequency can be calculated according to Equations ( 19) and (20), where RoCoF cyc is the RoCoF between successive AC cycles, indexed by k, T cyc is the cycle duration, and RoCoF roll is the rolling average RoCoF, indexed by 𝜉. N cyc represents the number of cycles within the window. In this paper, a measurement window of 500 ms has been considered, which is used by anti-islanding relays in Ireland [46].…”

Optimal Scheduling Method of Cogeneration System with Heat Storage Device Based on Memetic Algorithm

“…To improve the wind power consumption capacity and economical operation of the cogeneration system, literature [1] confirmed through the economic model predictive control framework that adding heat pump and electric boiler to traditional cogeneration systems can improve system flexibility and economy while balancing the district heating network. Literature [2] integrated the energy storage battery with the cogeneration system through the power electronic interface, which enhances the flexibility and frequency response of the system. It stabilizes the unit's output power fluctuation while considering the operating economy.…”

Integrated Battery and Heat Pump System for Decentralized Primary Frequency Control in Low-Inertia Microgrids

“…Authors in [12] proposed a solution for secondary frequency regulation based on synthetic inertia that the BESS reacts to high-frequency components of the frequency disturbances and the ASHP balances lowfrequency ones. A similar idea is later adopted for decentralized primary frequency regulation in [13] for a system that has both BESS and combined-heat-and-power (CHP).…”