Peer-Reviewed Journal Publications

Article 1 - Incentive Based Demand Response Program for Power System Flexibility Enhancement

Published in IEEE Transactions on Smart Grid, in May 2021

In this work we investigate the incentives for end users to join a Demand Response program through a novel contact type that pays based on the number of times the DR event is called upon. We assess the effect of this smart contract on the power dispatch problem to sustain grid reslience.

Abstract - This article proposes a DR program characterized by a novel compensation scheme. The proposed scheme recognizes the different characteristics of curtailment, such as the total length of curtailments within a window of time, or the number of separate curtailment events (i.e., curtailment startup), and compensates the end-user accordingly. The proposed compensation scheme features a piece-wise reward function comprised of two intervals. DR participants receive a onetime reward upfront when they enroll in the DR program and accept a set of predefined curtailment aspects. Curtailment aspects in excess of the agreed quantities are rewarded at a linear rate. This design is tailored to appeal to residential DR participants, and aims to secure sufficient flexibility at minimum cost. The parameters of the smart contract are optimized such that the system’s social welfare is maximized. The optimization problem is modeled as a mixedinteger linear program. Consequently, this article updates the unit-commitment (UC) formulation with the commitment aspects of DR units. The proposed extension to the UC problem considers the critical aspects of DR participation, such as: the total length of interruptions within a window, the frequency of interruptions within a time-window irrespective of their length, and the net energy deviation from the original load profile. Deployment of the smart DR contract in the unit dispatch problem requires translating DR participants’ characteristics to their equivalent aspects in conventional thermal generators, such as minimum up time, minimum down-time, start-up and shutdown costs. The obtained results demonstrate significant improvement in social welfare, notable reduction of curtailed renewable energy and reduction in extreme ramping events of conventional generators.

Article 2 - A New Index of Power System Flexibility: Response Delay (θ) of Distributed Devices

Published in IEEE Transactions on Smart Grid, in Sept 2019

In this work we investigate the different characteristics of end-user power flexibility that can be achieved and the importance of each characteristic to the grid dispatch. We develop a novel type of flexibility index: response delay and assess its importance for aligning with different reserve requirements and ancillary services that can be offered to the grid through Demand Response.

Abstract - Power system flexibility consists of three indices: ramping capability limit ( ρ), power capacity ( π), and energy capacity ( ε). The existing research body neglects the effect of demand response (DR) units' action delay time, and its effect on the system's contingency response. This paper proposes a fourth flexibility index, the Response Time Delay, denoted as ( θ), and investigates the isolated effect of this factor on the system. A novel extension on the security constrained optimal power flow formulation is presented in this paper, to explicitly model DR unit's response delay time. The value of the response delay ( θ) on the system's operation cost is determined. Making this information available to Virtual Power Plants (VPP) and aggregators empowers management of demand & distributed generation profiles, market design for ancillary services, and policy making for aggregators. It also supports making better investments decisions for all stakeholders. The proposed formulation is tested on a modified version of the IEEE14-bus system with DR units having different response characteristics. DR units yield a decrease in secure energy price, total system operation cost and up-reserve. On the other hand, DR units raise the price of down-reserve.

Article 3 - A Review of Power System Flexibility With High Penetration of Renewables

Published in IEEE Transactions on Power Systems, in July 2019

In this work we investigate power system flexibility and its impact on power grid resilience. It assesses the different type of reserve needed to operate a power grid securely and how this reserve requirement can be met through procurement of MW flexibility from end users through Demand Response.

Abstract - The notion of secure operation of power systems, with its present semantic, dates back to the last decade. Since then, tremendous research effort has investigated secure operation of the power system. Nevertheless, operators are still faced with security issues, with even larger uncertainty, however, caused by the integration of renewable energy sources (RES). The system's ability to cope with the volatility of RES and load becomes a critical issue in power system operation. This paper surveys the literature on the concepts of power system flexibility, indices of flexibility, and implementation of the concept of flexibility in power system security. The paper proceeds to review the origin of the reserve problem, the meaning of reserve, its technical classification and related economical aspects. The paper highlights the effect of renewables on these aspects, and suggests new research directions.

Article 4 - Investigating Emission Regulation Policy in the Electricity Sector: Modeling an Oligopolistic Electricity Market under Hourly Cap-and-Trade

Published in Energy Economics Journal, Elsevier, in Feb 2019

In this work we investigate the application of a cap-and-trade emission regulation scheme in an oligopolistic electricity market and assess the effect of the hourly market-clearing of the ensuing joint market-clearing problem.

Abstract - Global warming is one of the most alarming phenomena facing our planet today. There is a consensus among scientists that human-induced greenhouse gases (GHGs) should be regulated to slow down the heating of the Earth's oceans and atmosphere. As a major GHG producer, the electricity industry's emissions should be considered in any global emission regulation policy initiative. This paper develops an original equilibrium model for a cap-and-trade emission regulation scheme (CAT) applied to an oligopolistic electricity market. The model accounts for the strategic behavior of power companies under emission regulation and explicitly illustrates how this behavior is influenced by the scheme design. The model respects the electricity sector's emission targets over a commitment interval while accounting for the effect of these targets on the hourly operation of electricity markets, given hourly variations in system demand. Simulation results over different demand levels show that the model of the proposed policy is successful in meeting short-term emission targets by dispatching generation based on privately owned power generating companies' (Gencos') generation costs and emission intensities. The results signify the importance of accounting for the effects of hourly permit trading on hourly market clearing and hourly gaming strategies when studying the allocation of commitment interval permits among Gencos.

Article 5 - Exam Timetabling with Allowable Conflicts within a Time Window

Published in Computer and Industrial Engineering Journal, Elsevier, in Jan 2019

In this work we investigate the use of graph theory to solve a complex mathematical modeling problem.

Abstract - The exam timetabling problem is considered an NP-complete problem and its complexity depends on the different constraints and policies set by an institution’s administration. The goal of this work is to facilitate exam timetabling for Masdar Institute (MI), which is a graduate level institution. Besides the renowned constraint on conflicts for students, MI’s timetabling case includes the incorporation of venues’ limited capacities, special instructor requests, and the number of exams scheduled for one student within a preset window of days. To the best knowledge of the authors, the latter constraint is new to the literature. Moreover, it increases the problem’s complexity since it requires cross-validation on both student and course levels. This contrasts with conventional exam timetabling which only deals with checks on a course level. We introduce an integer programming (IP) formulation that captures all the studied constraints. The proposed formulation can solve small problems using commercial software; however, this formulation’s performance deteriorates as the problem size increases. Therefore, the paper proposes heuristics to solve medium and large sized problems in a timely manner. This study employs graph coloring algorithms that include a new approach, within the steps of the proposed exam timetabling heuristics. Four real-case studies from MI are solved to illustrate the feasibility and competitiveness of the proposed heuristic. Finally, a computational study is presented to benchmark the proposed heuristics against the IP formulation. The results show that the proposed heuristics are capable of obtaining optimal and near-optimal solutions in smaller computational time.

Article 6 - Advancing Cyber–Physical Sustainability through Integrated Analysis of Smart Power Systems: A Case Study on Electric Vehicles

Published in International Journal of Critical Infrastructure Protection, Elsevier, in Dec 2018

In this work we investigate the resilience of power systems with the evolution of smart grids and the enhanced use of cyber space. These smart systems have intrinsic vulnerabilities. A smarter power grid is more reliant on an ICT backbone. Such reliance renders the physical power system subjected to an ICT realm whose security depends on a set of metrics, and standards alien to those of classical power systems

Abstract - Satisfying the growing energy demand, power systems are required to increase their capacity and be able to distribute energy over wider geographical area. To maintain the reliability of such power systems, more dependence is placed on automating the process controlling the physical system. Such power systems are known as smart grids, where data is transmitted in real-time across the power grid facilitating automated actions. These smart systems have intrinsic vulnerabilities. A smarter power grid is more reliant on an ICT backbone. Such reliance renders the physical power system subjected to an ICT realm whose security depends on a set of metrics, and standards alien to those of classical power systems. The sustainability of a power system will depend on the secure and reliable operation of the new smart system. This paper proposes a comprehensive approach to solve the challenges enumerated above. The proposed approach sets the ground for new metrics of overall system sustainability, by dissecting the overall smart grid into three layers: the physical system, the SCADA system, and the ICT infrastructure. The proposed methodology is tested on the case of electric vehicles, where cyber intrusion scenarios are studied in light of their effect on the physical layer.

Article 7 - Development and Assessment of Simplified Building Representations under the Context of an Urban Energy Model: Application to Arid Climate Environment

Published in Energy and Building Journal, Elsevier, in Aug 2018

In this work we investigate the loss of accuracy versus gain in computational effort incurred by the use of different types of simplified building representations relative to a more detailed one when applied in a building case study.

Abstract - For buildings in arid areas, requiring significant cooling loads, predictions of long term building cooling loads and the development of accurate Building Energy Models (BEM's) are of critical importance. However, numerous challenges and limitations are encountered in the course of generating such energy models. Furthermore, recent studies have emphasized the integration of the urban heat island phenomena in modeling building energy behavior in urban environments. This study assesses the loss of accuracy versus gain in computational effort incurred by the use of different types of simplified building representations relative to a more detailed one when applied in a building case study. The study shows that such simplification results in limited loss of accuracy, when compared to a detailed model. The RC-based simplified model reported a satisfying level of performance and was thus used to simulate the building cooling load of the case in an urban context. Furthermore, results showed an anticipated increase of cooling load demonstrating the practicality of the developed simplified model to be used in this context.

Article 8 - Review of Water-Energy-Food Nexus Tools to Improve the Nexus Modelling Approach for Integrated Policy Making

Published in Environmental Science & Policy Journal, Elsevier, in Nov 2017

In this work we investigate Nexus modelling for integrated policy making to help policy makers, practitioners, and agencies trying to implement the Nexus Approach to identify a tool that is most suited to their modelling needs.

Abstract - The synergies and trade-offs between the water, energy, and food sectors are represented by the Water-Energy-Food Nexus. The Nexus Approach is an integrated decision making practice that can be used by policy makers to optimize these synergies and manage trade-offs. In this paper, the direction of the Nexus Approach regarding the development of modelling tools is explored. The objective of this paper is to review the existing Nexus modelling tools used for integrated policy making to determine and to help policy makers, practitioners, and agencies trying to implement the Nexus Approach to identify a tool that is most suited to their modelling needs. The predominant capabilities of the current tools lie in the understanding of Nexus complexity, consideration of financial elements in the tools, recognition of the importance of multiple Nexus Approach directions, incorporation of different time scales, and enhanced tool accessibility. The main limitations are the extensive data requirements of current tools, and the poor synergy between tools assessing individual Nexus areas. This enhanced overview of the existing tools allows policy makers to maximize the synergies between the Nexus areas, to avoid consumption dilemmas, and to facilitate sustainable development.

Article 9 - Energy Efficiency and Potential National Savings in UAE

Published in the U.A.E. State of Energy Report, by Ministry of Energy in U.A.E., in Jun 2017

Article 10 - Energy/Water Nexus Modeling Approach in the Context of Integrated Policy Making in UAE

Published in the U.A.E. State of Energy Report, by Ministry of Energy in U.A.E., in Jun 2017

Article 11 - Cyberattacks on Critical Infrastructure and Potential Sustainable Development Impacts

Published in descriptionCivil and Environmental Engineering: Concepts, Methodologies, Tools, and Applications - IGI Global, in Dec 2016

Abstract - Because of advancement in information and communication technologies, modern infrastructure systems are currently operated, monitored and controlled by automated systems such as distributed process control networks and supervisory control and data acquisition. Such systems will make the critical infrastructures in any country vulnerable to failures caused by either operational failures or to potential cyberattacks similar to Stuxnet and Night Dragon. The objective of this paper is to shed the light on the synergy between cybersecurity and sustainable development in relation to the potential social, economic, and environment consequences of potential cybersecurity attacks on critical infrastructures. Examples of both operational and cybersecurity incidents are shown including their sustainable development implications.

Article 12 - Potential Impact of Methane Hydrate Development on GCC and NEA Energy Trade, in Energy Relations and Policy Making in Asia

Published in Springer, in Nov 2016

Abstract - The emergence of unconventional hydrocarbons, such as methane hydrates, may have a major future impact on bilateral trade relations between the countries of Northeast Asia (NEA) and the Gulf Cooperation Council (GCC). In this paper, the historical energy trade relationship between the two regions is examined as well as the evolution and scientific basics of methane hydrates, the methods of methane hydrate extraction, the challenges faced in extraction, and the potential pricing of this alternative fuel source. The analysis shows the viability of methane hydrates as an alternative hydrocarbon as well as the current barriers to full exploitation of this alternative energy source. Policy recommendations are proposed based on the potential for NEA methane hydrate development to become a ‘black swan’ event for GCC countries.

Article 13 - The Effect of Implementing a Feed-in Tariff in Abu Dhabi UAE

Published in Applied Economics and Finance, in Oct 2016

Abstract - Although most countries in the world have been trying to introduce renewable energy into their power supplies to address issues related to the environment and energy security, the Middle East has the lowest overall renewable energy capacity in the world. However, there is currently a trend of accelerating renewable energy deployment with increased investment in the region for the purposes of improving energy security and independence and promoting long-term social and economic benefits. This study aims to examine the impact of implementing a feed-in tariff (FiT) in Abu Dhabi, United Arab Emirates. After a simulated test, it was found that the levelized cost of electricity (LCOE) and the current average unit cost of electricity were considerably divergent. That is to say, a large extra cost is incurred in order to deploy renewable energy in Abu Dhabi. In this context, the effectiveness of implementing a FiT in Abu Dhabi is confirmed. Furthermore, an estimation of the size of the renewable energy surcharge indicated that the impact of implementing a FiT would be enormous. For example, if the target rate of deploying renewable energy is set at 7%, a renewable energy surcharge equivalent to approximately one third of the total turnover of the electricity sector should be additionally imposed. It follows that the electricity rate will be raised by about thirty percent on average, unless subsidies are provided by the government.

Article 14 - Job Creation Potentials and Skill Requirements in, PV, CSP, Wind, Water-to-Energy and Energy Efficiency Value Chains

Published in Renewable and Sustainable Energy Reviews Journal, Elsevier, in Dec 2015

Abstract - Job creation is an important component of the socio-economic effects associated with the development and deployment of renewable energy (RE) and energy efficiency (EE) technologies. The potential contribution of the RE and EE sectors in creating new jobs affect the public policy as well as the allocation of public resources to promote related activities. This paper provides an overview on the job creation potential along the value chains of key RE and EE technologies by skill set, technological category and the stage in the life cycle of the development and deployment process. We summarize the existing approaches to estimate job creation effects of the RE and EE sectors and report the existing estimations of job creation figures by technology and capacity. The paper concludes with the cases studies on Germany, Spain, the United States and the Middle Eastern region to showcase the variation of job creation potential in different regions.

Article 15 - Driving Productivity & Profitability of Energy Efficiency in UAE

Published By General Electric, in Jan 2015

Abstract - While the interventions analyzed in this paper by no means represent an exhaustive list, they were identified by the collaborative team at Masdar Institute and General Electric as major sources for national wealth savings and an appropriate stepping stone for future research. In the paper, the potential national wealth savings for the U.A.E. government are calculated across different energy efficiency interventions using an in-house model developed at Masdar Institute. The savings are broken down according to their type, which include: fossil fuel subsidy savings (FSS) – from natural gas and diesel; electricity tariff subsidy savings (TSS); and opportunity cost savings (OCS) from the potential export of natural gas and diesel at a higher international market price

Article 15_Driving Productivity & Profitability of Energy Efficiency in the UAE

Article 16 - Formulation of an Integrated Energy Strategy for Abu Dhabi based on a Holistic Optimization of the Country's Energy Resources

Published By Energy Procedia Journal, Elsevier, in Nov 2014

Abstract - This paper is the initial phase of on going research work to develop a decision-making tool that employs a bottom-up model of the integrated energy sector in Abu Dhabi. It showcases the formulation framework and the modelling design that will facilitate scenario analysis leading into policy recommendations that will promote sustainability in this sector. The stability of Abu Dhabi's energy sector, hence the stability of its economy are strongly coupled to volatile fuel prices and exhaustible resources therefore explicitly reflecting a future of energy security concerns. As such, the technology-explicit model developed in this work will provide optimal energy diversification targets essential to Abu Dhabi's future energy security. The major strength of the model is its ability to capture existing energy flows starting from resource management to end use demand. The existing consumption trends are used to constrain the production function while allowing for the minimization of energy supply costs. A set of scenarios was introduced in this study to: i) assess how the roadmap to a low carbon economy should be paved; and ii) analyse the impact of current and future energy conservation efforts on the cost of electricity and the amount of imported natural gas. This paper presents the baseline modelling scenario results in an effort to devise Abu Dhabi's comprehensive energy strategy.

Article 17 - Emission Allowances Auction for an Oligopolistic Electricity Market Operating under Cap-and-Trade

Published By IET Generation, Transmission & Distribution Journal, Institution of Engineering & Technology, in Feb 2010

Abstract - The authors consider a yearly auction where electricity generating companies (Gencos) bid to receive yearly green house gas (GHG) emission allowances. Gencos sell electricity in an oligopolistic electricity market that clears on an hourly basis and operates under a cap-and-trade emissions regulation scheme. Gencos strategically self-allocate their yearly allowance into hourly allowances that they then use to take part in the hourly electricity market. If a Genco emits above or below its self-allocated allowance for that hour then, in the first case, the hourly deficit is made up by buying an allowance from an external market, whereas in the second the hourly allowance surplus is sold to the external market. Recognising that the levels of power and emissions produced by the Gencos as well as the associated prices throughout the year will be influenced by both the yearly and hourly allowances, the auction maximises an objective function that is equal not only to the total amount bid by the Gencos to obtain allowances but also includes the yearly social welfare. This study proposes an approach that considers all of the above-mentioned points in a coordinated fashion and can be viewed as a mathematical program (the allowance auction) subject to a Nash equilibrium problem (the distribution by each Genco of its yearly allowance into hourly allowances), which in turn is subject to the Cournot–Nash equilibrium conditions of the hourly oligopolistic electricity market.

Article 18 - Negotiating Bilateral Contracts in Electricity Markets

Published By IEEE Transactions on Power Systems, in May 2007

Abstract - In mixed pool/bilateral electricity markets, participants can sign forward bilateral contracts several months in advance of its delivery. In addition, generators may sell to and loads may buy from the pool at the spot price through the day-ahead or balancing markets. Forward bilateral contracts have the advantage of price predictability in comparison with the uncertain spot price. However, the risk is that such a contract commits the partners to a price that may be disadvantageous compared to the spot price. Here, we propose a systematic negotiation scheme through which a generator and load can reach a mutually beneficial and risk tolerable forward bilateral contract, either physical or financial. Under this approach, the generator and load respond rationally to a stream of bilateral bids/counter-bids and offers/counter-offers considering their respective benefits while accounting for the risks incurred by the prediction uncertainty in the pool spot price and other market parameters over the length of the contract. Each negotiating party can choose its own definition of risk which can be influenced by regret, value-at-risk or dispersion from the mean. Numerical tests show that this flexible negotiating approach can be readily put into practice

Article 19 - Carbon tax is Superior to Cap-and-Trade in an Oligopolistic Electricity Market

Published n Proceedings of International Conference on European Energy Markets, IEEE, Jun 2012

Abstract - For the same level of long-term emissions, we quantitatively compare the behaviour of an oligopolistic electricity market under cap and trade versus carbon tax. Under both emission regulation schemes, Gencos game by accounting for both generation cost and generation emission efficiencies. Under cap and trade, the social planner allocates a specified yearly emission cap on the electricity sector amongst the Gencos by maximizing social welfare. This allocation is conducted by recognizing that the Gencos will self-allocate these permits in the joint hourly electricity/permits market so as to maximize their long-term profits in a Nash-based manner. Moreover, in the joint hourly market, each Genco uses its self-allocated hourly permits to dispatch power and either buy permits in the global market in case of a deficit or sell in case of a surplus, all in a Nash-based strategic manner. Under carbon tax, the social planner imposes an hourly carbon tax whose parameters are computed so as: (1) to maximize yearly social welfare; (2) to end up with the same level of yearly emissions as with cap and trade. As under cap and trade, in executing these two steps, the social planner recognizes that the Gencos will game in the hourly electricity market (since under carbon tax there is no permits market) and that their gaming strategy will be affected by the carbon tax. Simulations suggest that, generally speaking, cap and trade offers greater gaming opportunities due to the presence of permits trading, allowing cheap Gencos to maintain market power despite their high emissions intensity. Moreover, the increased gaming opportunities under cap and trade tend to increase prices as well as rendering them more difficult to predict. In contrast, under carbon tax, low polluting Gencos tend to increase their market power thus making higher profits, thereby promoting greater investments in low emission technologies, despite their higher costs.

Article 20 - On Gaming in Electricity Markets under Cap-and-Trade

Published By Proceedings of Sustainable Alternative Energy Conference, IEEE, Sept 2009

Abstract - This paper examines the effect of gaming by electricity generating companies (Gencos) operating in an electricity market under cap-and-trade. We show how Gencos strategically offer on the basis of their allocated allowances and emission intensities and, through an example, examine how this gaming strategy affects the Gencos’ profits and the overall market equilibrium.