Energy is a vital input for social and economic development. As a result of the generalization of agricultural, industrial and domestic activities the demand for energy has increased remarkably, especially in emergent countries. This has meant rapid grower in the level of greenhouse gas emissions and the increase in fuel prices, which are the main driving forces behind efforts to utilize renewable energy sources more effectively, i.e. energy which comes from natural resources and is also naturally replenished. Despite the obvious advantages of renewable energy, it presents important drawbacks, such as the discontinuity of generation, as most renewable energy resources depend on the climate, which is why their use requires complex design, planning and control optimization methods. Fortunately, the continuous advances in computer hardware and software are allowing researchers to deal with these optimization problems using computational resources, as can be seen in the large number of optimization methods that have been applied to the renewable and sustainable energy field. This paper presents a review of the current state of the art in computational optimization methods applied to renewable and sustainable energy, offering a clear vision of the latest research advances in this field.

Optimization methods applied to renewable and sustainable energy: A review

In the current era of sustainable development, energy planning has become complex due to the involvement of multiple benchmarks like technical, social, economic and environmental. This in turn puts major constraints for decision makers to optimize energy alternatives independently and discretely especially in case of rural communities. In addition, topographical limitations concerning renewable energy systems which are mostly distributed in nature, the energy planning becomes more complicated. In such cases, decision analysis plays a vital role for designing such systems by considering various criteria and objectives even at disintegrated levels of electrification. Multiple criteria decision making (MCDM) is a branch of operational research dealing with finding optimal results in complex scenarios including various indicators, conflicting objectives and criteria. This tool is becoming popular in the field of energy planning due to the flexibility it provides to the decision makers to take decisions while considering all the criteria and objectives simultaneously. This article develops an insight into various MCDM techniques, progress made by considering renewable energy applications over MCDM methods and future prospects in this area. An extensive review in the sphere of sustainable energy has been performed by utilizing MCDM technique.

A review of multi criteria decision making (MCDM) towards sustainable renewable energy development

Energy systems models are important methods used to generate a range of insight and analysis on the supply and demand of energy. Developed over the second half of the twentieth century, they are now seeing increased relevance in the face of stringent climate policy, energy security and economic development concerns, and increasing challenges due to the changing nature of the twenty-first century energy system. In this paper, we look particularly at models relevant to national and international energy policy, grouping them into four categories: energy systems optimization models, energy systems simulation models, power systems and electricity market models, and qualitative and mixed-methods scenarios. We examine four challenges they face and the efforts being taken to address them: (1) resolving time and space, (2) balancing uncertainty and transparency, (3) addressing the growing complexity of the energy system, and (4) integrating human behavior and social risks and opportunities. In discussing these challenges, we present possible avenues for future research and make recommendations to ensure the continued relevance for energy systems models as important sources of information for policy-making.

https://www.pfenninger.org/publications-pdf/Pfenninger%20et%20al_2014_Energy%20systems%20modeling%20for%20twenty-first%20century%20energy%20challenges.pdf

Energy systems modeling for twenty-first century energy challenges

The integration of distributed generation (DG) units in power distribution networks has become increasingly important in recent years. The aim of the optimal DG placement (ODGP) is to provide the best locations and sizes of DGs to optimize electrical distribution network operation and planning taking into account DG capacity constraints. Several models and methods have been suggested for the solution of the ODGP problem. This paper presents an overview of the state of the art models and methods applied to the ODGP problem, analyzing and classifying current and future research trends in this field.

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Optimal Distributed Generation Placement in Power Distribution Networks: Models, Methods, and Future Research

Energy use in cities has attracted significant research in recent years. However such a broad topic inevitably results in number of alternative interpretations of the problem domain and the modelling tools used in its study. This paper seeks to pull together these strands by proposing a theoretical definition of an urban energy system model and then evaluating the state of current practice. Drawing on a review of 219 papers, five key areas of practice were identified – technology design, building design, urban climate, systems design, and policy assessment – each with distinct and incomplete interpretations of the problem domain. We also highlight a sixth field, land use and transportation modelling, which has direct relevance to the use of energy in cities but has been somewhat overlooked by the literature to date. Despite their diversity, these approaches to urban energy system modelling share four common challenges in understanding model complexity, data quality and uncertainty, model integration, and policy relevance. We then examine the opportunities for improving current practice in urban energy systems modelling, focusing on the potential of sensitivity analysis and cloud computing, data collection and integration techniques, and the use of activity-based modelling as an integrating framework. The results indicate that there is significant potential for urban energy systems modelling to move beyond single disciplinary approaches towards a sophisticated integrated perspective that more fully captures the theoretical intricacy of urban energy systems.

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A review of urban energy system models: Approaches, challenges and opportunities

It is difficult to estimate how much distributed generation (DG) capacity will be connected to distribution systems in the coming years; however, it is certain that increasing penetration levels require robust tools that help assess the capabilities and requirements of the networks in order to produce the best planning and control strategies. The work of this Task Force is focused on the numerous strategies and methods that have been developed in recent years to address DG integration and planning. This paper contains a critical review of the work in this field. Although there have been numerous publications in this area, widespread implementation of the methods has not taken place. The barriers to implementation of the advanced techniques are outlined, highlighting why network operators have been slow to pick up on the research to date. Furthermore, key challenges ahead which remain to be tackled are also described, many of which have come into clear focus with the current drive towards smarter distribution networks.

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State-of-the-Art Techniques and Challenges Ahead for Distributed Generation Planning and Optimization

The use of Distributed Energy Resources (DER) has been proposed as one of the possible solutions to today's energy and environmental challenges. The optimal integration of DER in distribution networks is essential to guarantee the best of resource, i.e. maximize their benefits, such as reduction of carbon emissions, reduction of network energy losses and to minimize the negative impacts, which can affect the network quality, cause network sterilization and increase investment and operation costs. Hence, DER planning is a multi-objective problem in which many objectives of interest, sometimes conflicting, need to be optimized simultaneously, and where a compromise for different perspectives (DER developer, Distribution System Operator, regulator) needs to be found. Appropriate multi-objective planning methods that consider technical, environmental and economic impacts of DER integration, and that are able to support a suitable model of stochastic DER and active networks, can provide a deep insight into the case specific and general advantages and drawbacks of DER. Consequently, the interest in multi-objective DER planning has increased in recent years, and a number of novel methods have been proposed in this area. This paper provides a timely review of the state-of-the-art in multi-objective DER planning, and discusses in detail the challenges, trends and latest developments in this field.

Multi-objective planning of distributed energy resources: A review of the state-of-the-art

The amount of distributed energy resources (DER) in the grid is continually increasing, and the potential benefits and drawbacks are becoming clearer. However, there is still a lack of clarity in how these multiple effects interact and which trade-offs should be made in the integration of new DER. There is a clear need for appropriate DER planning tools in the current market environment, in which both DER operators and distribution system operators (DSOs) may have multiple, often conflicting objectives and where uncertainty remains present as to which targets can be reached with a high amount of DER in the grid. A novel multi-objective planning framework is presented for the integration of stochastic and controllable DER in the distribution grid. A case study that illustrates the proposed framework is presented. Active DER management in terms of curtailment as well as dispatch of units is studied using the proposed multi-objective approach. Additionally, the extent to which active DER can be used as an alternative for grid reinforcements is analysed. The results show that the proposed multi-objective approach permits a better evaluation of the potential of active DER to support system operation.

Multi-objective planning framework for stochastic and controllable distributed energy resources

Power systems worldwide have gone through a transition from vertically integrated into liberalized energy markets. At the same time, increased environmental concerns are promoting the use of renewable and efficient generation technologies. Consequently, a growing number of small-scale Distributed Energy Resources (DER) are being installed in distribution systems. Passive operation of DER can result in severe grid operation problems. In contrast, active DER management can bring mutual benefits for the DER owner as well as Distribution System Operators (DSO). In this article a flexible multi-objective optimization scheme is presented in which DER placement and optimal ancillary services are evaluated and compared with conventional grid reinforcements. This allows assessing the potential of optimal active DER management and evaluating different tariff schemes for DER connection at different levels of DER in the grid. The proposed method uses a hybrid Strength Pareto Evolutionary Algorithm (SPEA2) with a distribution Optimal Power Flow (OPF). Results are analyzed using the UKGDS 355-bus system.

Opportunities for active DER management in deferral of distribution system reinforcements

This paper presents an outline for a development stage model of the UK energy infrastructure The model will use transition pathways as inputs to simulate the UK energy infrastructure toward 2050 Transition pathways are socio technical narratives that are used here to describe possible evolutions of the UK energy industry as it moves towards 2050 and a lower carbon economy It is the aim of the authors to use an energy infrastructure model - based on the concept of ‘energy hubs’ proposed elsewhere - to determine the energy infrastructure needed to facilitate the conversions and transfers of energy that will occur as the energy sector in the UK moves towards a lower carbon economy

Arturo D. Alarcon-Rodriguez

Papers

State-of-the-Art Techniques and Challenges Ahead for Distributed Generation Planning and Optimization

Multi-objective planning of distributed energy resources: A review of the state-of-the-art

Multi-objective planning framework for stochastic and controllable distributed energy resources

Opportunities for active DER management in deferral of distribution system reinforcements

Outline for an integrated multiple energy carrier model of the UK energy infrastructure