I Ioannis Lampropoulos

Assessing the economic benefits of flexible residential load participation in the Dutch day-ahead auction and balancing market

In this paper the authors present the potential cost-savings that may arise due to demand response from residential customers participating in the Amsterdam Power eXchange (APX) day-ahead auction and the Dutch balancing energy market which is organised by TenneT, the Dutch Transmission System Operator (TSO). For this purpose, a model for residential demand response is developed that utilises as input historical market data. Furthermore, the model synthesises a daily load profile based on load profiles of Dutch residential customers and simulated data to represent aggregate demands of domestic appliances and electric vehicles. The model is built around the concept of the aggregator, an envisioned legal entity, that contracts large amounts of residential customers and then coordinates them in real-time under different objectives (i.e. economic optimisation based on predicted day-ahead prices and the provision of balancing energy). Simulation results show that the potential economic benefits of residential demand response, on the Dutch electricity markets, is relatively low on a per household basis, but not negligible for the business case of the aggregator.

A Predictive Control Scheme for Real-Time Demand Response Applications

In this work, the focus is placed on the proof of concept of a novel control scheme for demand response. The control architecture considers a uniform representation of non-homogeneous distributed energy resources and allows the participation of virtually all system users in electricity markets. The proposed scheme captures the operational planning, the real-time operations, the verification of the energy and service provision, and the financial settlement. The research involves the experimental verification of the proposed control and communication architecture between the aggregator and a system user in a laboratory environment. Emphasis is given on the real-time operations, whereas the case study is about the domestic freezer appliance. The convergence of the demand response system under load frequency control is investigated through simulation studies and the time response is compared to that of conventional balance suppliers in The Netherlands.

History of demand side management and classification of demand response control schemes

The scope of this paper is to provide a review on the topic of demand side management. A historical overview provides a critical insight to applied cases, while the discovery of new evidence calls for reconsideration of the design of demand response control schemes. The developments at the demand side are analyzed, and philosophical considerations are made with respect to envisioned energy management systems. Finally, the authors classify demand response control schemes based on the formulation of the rate structures and the employed technology. This classification follows a historical order, and addresses both applied cases and research developments.

A predictive control scheme for automated demand response mechanisms

The development of demand response mechanisms can provide a considerable option for the integration of renewable energy sources and the establishment of efficient generation and delivery of electrical power. The full potential of demand response can be significant, but its exploration still remains a challenge mainly due to the non-homogeneity and the distributed nature of energy resources. Recent advances in information and communication technologies create new opportunities for close to real-time adaptation of the demand for electricity to the actual system needs. However, there have been many different approaches in transforming this vision into practical applications. Herewith, a novel control scheme for automated demand response mechanisms is proposed based on the application of predictive control techniques. The proposed scheme supports the large-scale implementation of demand response programs, and captures the planning phase, the real-time operations, the verification of the energy and service provision, and the financial settlement.

Predictive control of a domestic freezer for real-time demand response applications

Demand side management and demand response aim to maximize the efficiency of the electricity delivery process by exploiting the flexibility of customers. At residential level, demand response can be applied only to a limited number of appliances, through load management, due to user intervention or dedicated automated actions. One category of appliances which concur well with demand response is the thermostatically controlled appliances. They operate in cycles and maintain the temperature of a process around a set-point and within certain temperature limits. When demand response is applied, the thermostatically controlled appliance is utilized as an energy buffer and a temporary increase or decrease in power and energy consumption is induced. This work focuses on the application of demand response to the operation of a typical domestic freezer. Real-time predictive control models are developed for this application and are validated during practical experiments.

Analysis of the market-based service provision for operating reserves in the Netherlands

The electricity sector liberalisation in Europe has contributed significantly towards the creation of competitive markets. The wholesale trading of electricity consists of a market-based segment often complemented by markets for ancillary services, including the provision of operating reserves. In this paper, the authors examine and classify operating reserves that are currently traded in the Netherlands. The principles, under which the provision of these reserves is verified by the Dutch Transmission System Operator (TSO), are illustrated, and inefficiencies of the current verification approach are identified. The verification process of the TSO takes into account specific conditions, but the criteria for assessing the quality of the service provision are not explicitly defined. Furthermore, only a limited number of cases can be assessed due to the non-automated nature of the process. Finally, a proposal is made for the development of an automated analysis tool for assessing the service provision of market parties. This proposal emphasises the need for more robust verification processes in line with the increasing integration of electricity markets in Europe.

Day-ahead economic scheduling of energy storage

This article addresses the day-ahead economic optimisation of energy storage systems within the setting of electricity spot markets. The case study is about a lithium-ion battery system integrated in a low voltage distribution grid with residential customers and photovoltaic generation in the Netherlands, whereas the optimisation objective is to maximise revenues from energy arbitrage in the day-ahead auction. Assuming accurate predictions of the photovoltaic generation, the residential load and the market clearing prices, the constrained optimisation problem is formulated as the minimisation of a cost function, and is solved by utilising an internal model of the battery system to plan the future response of the charging and discharging process. Emphasis is given on the effect of the system efficiency, which significantly impacts the economic performance due to energy losses during the charging and discharging cycles.

Demand side management of electric boilers

In this paper a control strategy for demand side management of electric storage water heaters is presented. The proposed algorithm reduces load variations, during any given optimization period, taken into account the base load. The algorithm uses the energy consumption model of the water heater as an input. The strategy can be applied to optimize present control strategies based on the existing ripple control technology, in order to improve the performance of the power system.

The impact of electricity market design on periodic network frequency excursions

In an electrical power system there must always be a balance between generation and load of electricity. Any mismatch between generation and load will, in a synchronous system, instantaneously lead to a deviation of the grid frequency from its nominal value in the whole system. It is observed that grid frequency deviations occur at hourly and half-hourly transitions, especially during morning and evening hours when the rate of change of load is high. The origin of these frequency deviations lies in the economic dispatch of generation which is ever more cost optimized. As generation companies have the obligation to provide a certain amount of energy per trading period (defined as Program Time Unit), they have little (or no) incentive to follow the power demand profile and therefore rather optimize their generation based on this energy constraint, which results in stepwise power generation profiles. The restructuring of the electricity business is considered a plausible cause for this, as it provides an incentive to further optimize the economic dispatch without taking into account mismatch between generation and load within the program time unit.

Enabling Flexibility from Demand-Side Resources Through Aggregator Companies

In recent years, several business models of the aggregator company have emerged in Europe, in response to a general quest for flexibility in power system operations. A systematic approach of analysing the organisational arrangements underlying a business model is still lacking, whereas the available information on the potential of aggregated resources in electricity markets is limited. This work contributes to the systematic development of the business model concept of an aggregator company, and provides insight into its economic potential. A set of elements is identified that can be used for analysing the various implementations of a business model. A revenue analysis is performed based on historical data from the day-ahead market and the imbalance settlement system in the Netherlands. The case study is about a hypothetical implementation of the aggregator company with focus on residential demand-side resources. The results show a significant theoretical potential and suggest an interesting business case.