Adequacy modeling and evaluation of multi-carrier energy systems to supply energy services from different infrastructures

doi:10.1016/j.energy.2016.04.116

Energy

Volume 109, 15 August 2016, Pages 1095-1106

https://doi.org/10.1016/j.energy.2016.04.116 Get rights and content

Highlights

•
Some energy services can be provided through different types of energy supply.
•
Availability of alternative supply to a service creates load-side dependency.
•
Load-side dependency is modeled for multi-carrier energy systems.
•
Limitation of primary resources is considered in adequacy modeling.
•
Incorporating load-side dependency and resource limitations yields a more realistic model.

Abstract

Development of MCESs (Multi-Carrier Energy Systems) can make the energy supply more reliable and efficient. Due to the redundancy potential of these systems, in case of an energy carrier interruption, consumers may be able to supply part of their loads from other energy infrastructures. This paper presents an approach for evaluating the adequacy of MCESs considering the dependencies of energy carriers at both generation side and demand side. To model the adequacy of generation systems supplying different forms of energy, a new methodology is presented, which considers the limitation of primary resources and takes into account the COPTs (Capacity Outage Probability Tables) of different energy infrastructure components. The model incorporates the impact of load dependencies at the demand side. A new focus is set up, by considering the outputs as services that can be provided through different types of energy supply. Illustrative results are presented to show the application of the proposed models to multi-energy systems.

Introduction

The adequacy of different energy infrastructures is often analyzed independently in planning studies [1], [2], [3]. However, in a MCES (Multi-Carrier Energy System) from the primary resources to the end-users, energy carriers can be converted into each other. Fig. 1 shows a MCES in which converters and appliances are used to provide different services from different energy infrastructures. In such a multi-carrier environment, there are some primary resources (e.g., natural gas) that are consumed by several energy infrastructures in order to supply different energy carriers demand (e.g., gas, heat and electricity) [4]. Since failure or high demand of one energy infrastructure can result in shortage of these primary resources, it is necessary to consider resource sharing in adequacy analysis of energy systems.

The focus in this paper is set on the energy-based services than can be provided through different types of energy supply systems or infrastructures. The possibility of providing a given service from different energy sources is represented by introducing links among energy converters and appliances. The focus on the services is a novel view with respect to the traditional way to describe the outputs as given energy values. From the energy services point of view, the energy used to provide the same service (e.g., maintaining the temperature constant in an ambient, or cooking a given type of food) can be different if different energy sources are deployed.

The energy converters link the inputs from various energy sources to the corresponding outputs. As the energy converters can establish redundant connections between inputs and outputs, reliability of supply can be increased from the consumers’ perspective, because supplying the services are no longer fully dependent on a single energy source or network [5]. However, from the upstream energy system perspective, an outage of one energy carrier forces the consumers to replace their demand with another, which may propagate the energy curtailment to other networks. For example, in case of gas curtailment, the consumers will demand more electricity for using electric heaters instead of gas heaters, which may make the electrical power system to be at risk. Therefore, loads dependency should also be considered in adequacy analysis studies.

Reliability evaluation of the electric power system has been studied in different researches. In Ref. [1] the power system reliability problem is evaluated in three Hierarchical Levels: reliability of the generation system (HLI), reliability of the composite generation and transmission system (HLII), and reliability of the complete system (HLIII). Moreover, the analysis of the power system reliability considering the reliability of gas supply has been addressed in several researches [6], [7], [8], [9]. In Ref. [6] the NERC (North American Electric Reliability Corporation) highlights the impact of natural gas delivery on reliability of the electric power system and considers unexpected fuel transportation contingencies in power systems adequacy. The risks associated with the security of the natural gas network with gas-fired generation units are addressed in Refs. [7], [8], [9] and security-constrained unit commitment is presented to consider the short-time impact of natural gas prices on generation units scheduling.

One the other hand, the development of energy converter technologies (e.g., CHP (Combined Heat and Power), fuel cells) has increased the inter-dependency between different forms of energy [10], [11]. This issue has attracted the attention of researchers to investigate on the characteristics of multi-carrier energy systems [12], [13], [14]. Reference [12] presents a coupling matrix to model the relation between the energy at the inputs and the loads in a MCEH (Multi-Carrier Energy Hub). In Ref. [15] the previous presented model of MCEHs is extended to consider the stochastic behavior of customers and model the implementation of demand response programs. Reference [16] presents a comprehensive linearized model for optimal design of a MCEH. Reference [17] analyzes distributed multi-generation systems in MCESs and discusses the benefits of these systems. The method for combined optimization of energy systems presented in Ref. [18] includes multiple energy carriers and conversion between different energy infrastructures. Reference [19] decomposes the problem of multi-carrier OPF (Optimal Power Flow) into its traditional separate OPF problem to develop a general modeling framework for coupled power flow studies.

In addition to the financial benefits of MCESs, for the purpose of enhancing the operational efficiency of the energy systems a key benefit of MCESs can be identified in the area of reliability of supply. A model for reliability evaluation of a MCEH is presented in Ref. [5], considering the power inputs to be always available. A reliability evaluation analysis of MCEHs is presented in Ref. [20] considering the dynamic behavior of thermal loads. Reference [21] developed a model predictive control strategy to mitigate the effects of cascades in transmission lines and gas pipeline networks; to minimize load-shedding after a disturbance, line outages are incorporated into the economic dispatch formulation.

In previous studies, the electric power system adequacy has been evaluated based on capacity availability of power plants, without considering the limitation of the primary resources of energy. The study presented in this paper considers the details of supply side and energy services. The scope of the classical HLI analysis is extended to incorporate the multi-energy dependencies of the services and the limitations on primary resource availability.

The specific contributions of this paper are:

1)
modeling the adequacy of MCESs including both the generation side and the demand side, taking into account that some energy services can be provided through different types of energy supply;
2)
developing a model that considers the mutual dependency of multi-carrier energy demand in adequacy analysis, considering that availability of alternative supply to a service creates load-side dependency;
3)
incorporating the limitation of primary energy resources in the formulation of the adequacy analysis problem.

In order to assign the primary energy resources to different energy infrastructures and calculate the energy not supplied in each infrastructure, the problem is formulated in a linear manner that can be implemented in multiple system states and for multiple time periods. Similarly to other HLI studies, the energy distribution networks are assumed to be always available.

The rest of the paper is organized as follows: Section 2 addresses system modeling and problem formulation. Section 3 discusses the adequacy evaluation procedure. Section 4 presents the numerical study application. Section 5 contains the conclusions.

Section snippets

Modeling the multi-carrier demand in normal conditions

To consider the dependency of different forms of energy in the demand side, this section introduces a model that extends the models presented in literature. As shown in Fig. 2, the general form of a consuming MCEH has multiple ports, including several inputs (e.g., electricity, natural gas and district heat) to supply different loads (e.g., electricity and heating) at output ports [12], [13]. Between the ports, different energy carriers are converted into each other using energy converters to

Adequacy evaluation procedure

Presented studies for adequacy evaluation of electric generation systems establish and calculate the reliability indices considering the LDC (Load Duration Curve) [1]. However, in our problem, it is not possible to use LDCs, because for a load level of one energy carrier (e.g., electricity), it may be different load levels of other carriers (e.g., gas), and thus, converting load curves into LDCs will put down the coincidence of the load levels during the time and the mutual dependence of loads

Numerical results and discussion

In this section a test system (Fig. 3) is used to show the effectiveness of the presented modeling approach. The initial resources of the system are assumed to be diesel and gas. The gas resource is provided through two 10-MW gas refinery units and the maximum available capacity of diesel is considered to be 2 MW. There are several resources and energy converters in the generation side as shown in Table 1 to provide three energy infrastructures: electricity, gas and heat. Moreover, a CHP

Conclusion

This paper has presented a new way to model the adequacy of an energy system considering multi-energy carriers at both generation and demand sides, setting the focus on the provision of energy services.

Two scenarios have been modeled and simulated. The first scenario considered the generation side and assumed that there is no dependency between the demand of energy carriers. The second scenario assumed that in case of interruption, consumers can benefit from their energy converters and deploy

References (24)

A. Rusin et al.
Trends of changes in the power generation system structure and their impact on the system reliability
Energy
(2015)
F. Monforti et al.
A MonteCarlo approach for assessing the adequacy of the European gas transmission system under supply crisis conditions
Energy Policy
(2010)
R. Egging et al.
The World Gas Model: a multi-period mixed complementarity model for the global natural gas market
Energy
(2010)
G. Koeppel et al.
Reliability modeling of multi-carrier energy systems
Energy
(2009)
A. Shabanpour-Haghighi et al.
Multi-objective operation management of a multi-carrier energy system
Energy
(2015)
R. Evins et al.
New formulations of the ‘energy hub’ model to address operational constraints
Energy
(2014)
P. Mancarella
MES (multi-energy systems): an overview of concepts and evaluation models
Energy
(2014)
G. Chicco et al.
Distributed multi-generation: a comprehensive view
Renew Sustain Energy Rev
(2009)
M.H. Shariatkhah et al.
Modeling the reliability of multi-carrier energy systems considering dynamic behavior of thermal loads
Energy Build
(2015)
R. Billinton et al.
Reliability evaluation of power systems
(1996)

North American Electric Reliability Corporation (NERC)

Long-term reliability assessment

(2006)

T. Li et al.

Interdependency of natural gas network and power system security

IEEE Trans Power Syst

(2008)

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Adequacy modeling and evaluation of multi-carrier energy systems to supply energy services from different infrastructures

Highlights

Abstract

Introduction

Section snippets

Modeling the multi-carrier demand in normal conditions

Adequacy evaluation procedure

Numerical results and discussion

Conclusion

Energy

Energy Policy

Energy

Energy

Energy

Energy

Energy

Renew Sustain Energy Rev

Energy Build

Reliability evaluation of power systems

Long-term reliability assessment

Interdependency of natural gas network and power system security

IEEE Trans Power Syst