Management and Activation of Energy Flexibility at Building and Market Level: A Residential Case Study

Chapter 2 - Building energy flexibility: definitions, sources, indicators, and quantification methods

Water scarcity and the dependence on fossil fuels as a primary source of energy are crucial problems for a number of arid countries. The integration of energy and water systems presents a possible solution for both issues. The flexibility of a desalination system can increase the possibility for the penetration of intermittent renewable energy sources and thus provide both fresh water and the potential for the local production of clean energy. Jordan is the fourth most water deprived country in the world and is also highly dependent on energy import. Almost all of its primary energy comes from imported fossil fuels, mostly from natural gas. It is a country rich in wind and solar energy but unfortunately, almost no utilization of that potential. The integration of desalination systems and renewable energy sources is a possible solution both for Jordan’s water and energy supply. The goal of this paper is to demonstrate the desalination module in the H2RES model using Jordan as a case study. H2RES is a flexible energy modelling tool used for the balancing of energy supply and demand on an hourly basis. It is capable of demonstrating the benefits of water and energy integration for the purpose of increasing the penetration of intermittent renewables and the reduction of CO2 emissions. For this purpose, four scenarios have been created. The first one is a business as usual scenario with no desalination, a desalination scenario and two desalination scenarios that utilize the produced brine as energy storage in pump hydro plants. The results will show that the utilization of desalination, especially in the case where desalination is combined with pump storage, can help increase the penetration of renewable energy sources into the electrical grid and thus help decrease the dependence on energy import and reduce the CO2 emissions of the energy system.

Generic characterization method for energy flexibility: Applied to structural thermal storage in residential buildings

The high rate of penetration of renewable energy sources leads to challenges in planning and controlling the production, transmission and distribution of energy. A possible solution lies within the change from traditional supply side management to demand side management. Buildings are good candidates for implementing a demand response model since they account for around 39% of global final energy use and are stably connected to all infrastructure networks. As a result, employing buildings as "players" in energy networks is considered now more than ever compelling. Recently, significant improvement has been denoted in the thermal efficiency of the building shell and the energy efficiency of the HVAC systems in new and renovated buildings. However, despite the reduction in energy demand regarding the space conditioning, buildings continue to be passive end users of the energy system. In order to ensure that they are capable of providing the necessary energy flexibility to balance intermittent energy production, a first step is to establish a formal, standard, and robust method of characterizing the energy flexibility provided on the demand side. Buildings can supply flexibility in a variety of ways, but there is currently no fixed and consistent method for quantifying the amount of flexibility a building can provide to future energy systems. In this paper, an overview of the literature on building energy flexibility will be offered, as well as an introduction to the concept of building energy flexibility and the methodologies used to define and evaluate it.

Building energy flexibility may support higher penetration of renewable energy sources into electrical grids in the near future. In this work, thermal inertia of a family house is evaluated using building energy simulation tools. The simulation study is based on the interior temperature response to a sudden shutdown of the heating source while considering theoretical boundary conditions (i.e. constant exterior conditions). This experiment is intended to assess the energy flexibility potential of both building and its heating system. In addition, this simulation analysis elaborates the sensitivity of the interior temperature response to the model parameters such as the storage tank volume, the thickness of insulation and inner wall layers. The results of this study help to understand the thermal capacity of buildings including their heating systems.

The present paper presents an analytical model for the evaluation of short-term frequency response in isolated power grids with increasing penetration of renewable energy sources. The analysis includes synthetic inertia and primary frequency control schemes proposed in the literature for wind power plants. Thus, frequency response in future insular scenarios can be estimated. The analytical model is verified with a real-case study: Terceira island in the Acores, a small size European island with high potential in renewable energy sources.

The high penetration of inverter-fed renewable energy sources (RESs) in modern energy systems has led to a reduction in the system’s inertial response. This reduction in the rotational inertial response is associated with synchronous generation and might result in a deteriorated frequency response following a power disturbance. This paper investigates the frequency stability of the Kingdom of Saudi Arabia’s (KSA) grid. It includes a description of the changing energy landscape of the KSA’s electricity grid and an investigation of the impact of high penetration levels of inverter-fed RESs on the dynamic behavior of the KSA grid. The impact of RESs has been studied through a simulation of case studies of the future KSA power system using the MATLAB/Simulink simulation software. The frequency stability of the KSA’s power system has been evaluated with various RES levels under peak and base load conditions. The simulation results show that the high penetration levels of RESs dramatically affect the system’s frequency response, especially under off-peak conditions. In addition, the significance of battery energy storage systems (BESSs) for compensating the reduction in the system inertial response has been addressed. The results show the effectiveness of aggregated BESSs for enhancing the system frequency control of the KSA grid.

An increase in the penetration of renewable energy sources in the electrical production has been matched by the emergence of many and varied challenges and problems. Among the most important challenges is finding the smart technologies and algorithms which are capable of achieving efficient solutions. This chapter provides an expanded view of the uses of the particle swarm optimization (PSO) algorithm in the renewable energy systems field. Additionally, it describes how the algorithm can be developed to cope with problems related to renewable energies to achieve desired goals. The PSO algorithm was used to solve many problems in the renewable energy systems, such as in optimal hybrid power systems, optimal sizing, and optimal net present cost, among others, where the PSO algorithm showed its high adaptability in problem-solving. Further, many researchers proceeded with the study and development of the PSO algorithm. In contrast, other researchers tried to hybridize it with different algorithms to be more efficient and convenient to overcome some of the problems and challenges that they encountered. The renewable energy systems have several issues to discuss, such as the cost of investment, the feasible technical criteria, optimal control, and the ecological problems as well as the social effect. Overall, studies and research have proven that the PSO algorithm is one of the best algorithms used in the field of renewable energy. This is attributed to the algorithm’s simplicity, high efficiency, and effectiveness compared to other algorithms and optimization methods.

A bottom-up optimization model for the long-term energy planning of the Greek power supply sector integrating mainland and insular electric systems

The adoption of a planning tool software platform for optimized polygeneration design and operation – A district cooling application in South-East Asia

In the context of electric vehicles integration in energy districts with the growing penetration of renewable energy sources (RES), this paper provides a method to manage the aggregate charging power flows optimizing self-consumption for flattening the load curve, and optimally exploit the intermittent RES. Under low internal RES availability, the proposed smart charging algorithm aims to guarantee an overall good state of charge of vehicles at the departure instant. This is achieved through a charging management system that differently allocates the power among the electric vehicles based on their battery charging level without involving absorption from the external grid. A reference scenario based on a real case study is performed to evaluate the proposal. This consists of an industrial area with photovoltaic plants and electrical loads. Finally, improvement in smart charging performance, especially under medium-low irradiance availability, is shown.

The operation of electric and heat grids alike is complicated due to the dynamic demand, with the increasing penetration of renewable energy sources adding to the problem. In order to improve the integration of variable renewable energy sources, the flexibility of the system needs to be improved. This paper proposed a novel characterization of the short-term energy flexibility, which was further utilized for the district heating capacity extension. The soft-linking of the models includes feedback, but the added computational complexity is kept at a minimum. Compared to the other literature in the field, due to the accurate characterization of the dynamics of the energy flexibility, flexibility is utilized much more frequently. The method was demonstrated for the case of the district heating of Zagreb. Results showed that both capital and operational savings can be achieved by adopting the proposed method. In the best performing scenario, which included the capacity extension planning, the savings of the district heating system were 5.4%. The extensive power exchange in the best performing scenario meant that the flexibility was used to help balancing the power grid as well.

Flexibility can be defined as the power system’s ability to respond to both expected and unexpected changes, on either the demand or supply side. This concept contributes to improving the grid’s stability allowing a higher penetration of renewable energy sources. Residential energy flexibility is considered an efficient concept for combating the excessive need to balance supply and demand. Shiftable appliances and residential energy storage systems are the main sources of residential energy flexibility. In this chapter, we discuss energy scheduling and quantification methods that facilitate the enhancement of building energy flexibility.

A scalable demand-side energy management control strategy for large residential districts based on an attention-driven multi-agent DRL approach

The integration of multi-energy systems to meet the energy demand of buildings represents one of the most promising solutions for improving the energy performance of the sector. The energy flexibility provided by the building is paramount to allowing optimal management of the different available resources. The objective of this work is to highlight the effectiveness of exploiting building energy flexibility provided by thermostatically controlled loads (TCLs) in order to manage multi-energy systems (MES) through model predictive control (MPC), such that energy flexibility can be regarded as an additional energy source in MESs. Considering the growing demand for space cooling, a case study in which the MPC is used to satisfy the cooling demand of a reference building is tested. The multi-energy sources include electricity from the power grid and photovoltaic modules (both of which are used to feed a variable-load heat pump), and a district cooling network. To evaluate the varying contributions of energy flexibility in resource management, different objective functions—namely, the minimization of the withdrawal of energy from the grid, of the total energy cost and of the total primary energy consumption—are tested in the MPC. The results highlight that using energy flexibility as an additional energy source makes it possible to achieve improvements in the energy performance of an MES building based on the objective function implemented, i.e., a reduction of 53% for the use of electricity taken from the grid, a 43% cost reduction, and a 17% primary energy reduction. This paper also reflects on the impact that the individual optimization of a building with a multi-energy system could have on other users sharing the same energy sources.