The low-carbon building has been proposed to mitigate the climate change caused by environmental problems and realize carbon neutrality in urban areas. In addition, the integrated energy system (IES) has been develope...
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The low-carbon building has been proposed to mitigate the climate change caused by environmental problems and realize carbon neutrality in urban areas. In addition, the integrated energy system (IES) has been developed to reduce renewable energy curtailment in the power distribution system and improve energy efficiency due to the independent operation of traditional energy systems. In this paper, we propose a stochastic planning method for low-carbon building IES, in which the Vehicle to Grid (V2G) is also considered to further increase the flexibility of low-carbon buildings. The proposed planning method optimizes the investment and operation costs, and CO2 emission of the building IES, to achieve the maximum benefit of the low-carbon building and help realize carbon neutrality. By considering the uncertainty of distributed renewable energy, multi-energy load fluctuation and the random behavior of EV users, a two-stage stochastic programming model is formulated with chance constraints, in which the heuristic moment matching scenario generation (HMMSG) and sample average approximation (SAA) methods are applied to deal with the uncertainties. In the case study, a real IES office building in Shanghai, where photovoltaic (PV), energy storage system (ESS), fuel cell (FC), EV, etc. are included as planning options, is used as the test system to verify the effectiveness of the proposed planning method, and the functions of the ESS and EV in IES are analyzed in detail in different operation scenarios. The case study results show that the proposed planning scheme can reduce the total cost and carbon emission significantly. (c) 2017 Elsevier Inc. All rights reserved.
In this paper, we examine a selling environment where a manufacturer-controlled retailer and an independent retailer sell a slow-moving A item. The manufacturer offers the independent retailer a price protection contr...
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In this paper, we examine a selling environment where a manufacturer-controlled retailer and an independent retailer sell a slow-moving A item. The manufacturer offers the independent retailer a price protection contract stipulating that the manufacturer reimburses the independent retailer in case of a reduction in the wholesale price. The price set by the independent retailer is assumed to be determined by Retail Fixed Markdown (RFM) policy. The manufacturer also offers the independent retailer a special discount rate for the replenishment orders and the retailers are assumed to follow (R, S) inventory replenishment policy. The manufacturer adopts a periodic-review pricing strategy and the mean demand observed by each retailer in a given period depends on the prices. We also take the customers choosing no-purchase option into account. We employ multinomial logit (MNL) models to forecast customers' preferences based on retail prices. The retailers' market shares are esti-mated by customized choice probability functions. We propose stochastic programming models to determine the manufacturer's pricing strategy. Then, we propose a variant stochastic Dual Dynamic programming (SDDP) algorithm to determine the manufacturer's approximately optimal pricing strategy by getting around three curses of dimensionality. Then, we move on to the observations on the impact of four critically important contractual parameters on the price, the market shares and the expected total net profits and finally discuss some possible approaches for the selection of the best compromise values of those contractual parameters.
In planning evacuation services against the threat of disasters, it is important to optimize pickup point location and rescue vehicle routing decisions while recognizing the risks of service disruptions. In this paper...
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In planning evacuation services against the threat of disasters, it is important to optimize pickup point location and rescue vehicle routing decisions while recognizing the risks of service disruptions. In this paper, a reliable location and routing model with backup service plans is proposed to plan targeted strategic evacuation, which minimizes the total expected cost for deployment of pickup stations, rescue vehicle routing, and evacuee assignments and exposure while the service is subject to probabilistic disruptions. We formulate the problem as a mixed-integer non-linear program, and develop two customized solution algorithms, one based on Lagrangian relaxation (LR) and the other based on meta-heuristic, to decompose and solve the problem. Numerical experiments with various parameters are conducted to not only demonstrate the applicability of the proposed model and effectiveness of the solution algorithms, but also to draw managerial insights. The impacts of demand distribution, facility cost, disruption probability, and evacuee exposure risk are assessed in a series of sensitivity analyses, so as to inform agencies how to carefully consider these factors while developing a reliable targeted evacuation service plan.
This paper aims to provide an improvement in the modeling of supply chain designs by incorporating correlated uncertainty among multiple parameters, resulting in a more resilient design. A new methodology to generate ...
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This paper aims to provide an improvement in the modeling of supply chain designs by incorporating correlated uncertainty among multiple parameters, resulting in a more resilient design. A new methodology to generate forecasts for historically correlated time series, regardless of their underlying probability distributions, is presented and applied to generate scenarios for energy and carbon prices, which historically proved to be correlated. These scenarios are then used in a stochastic computation to obtain a three-echelon supply chain design in Europe maximizing the economic performance. The emissions were monetarized through the incorporation of the European Union cap-and-trade emissions trading system into the model. The social impact of the supply chain network is measured in terms of the direct, indirect and induced jobs it creates, which are proportional to the economic performance. By combining the developed methodology with data mining algorithms, a reduction in the number of required scenarios by more than 90% was achieved. The numerical case study moreover shows that the stochastic design ensures an average reduction of emissions by more than 3 ktons compared to the use of a deterministic approach. In comparison, the computation of a stochastic supply chain design without parameter correlation takes 5 times longer.
This paper proposes an operational planning model based on optimal active and reactive power control strategies to enhance solar photovoltaics (PV)' hosting capacity in distribution networks. Reactive power contro...
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This paper proposes an operational planning model based on optimal active and reactive power control strategies to enhance solar photovoltaics (PV)' hosting capacity in distribution networks. Reactive power control is carried out through optimum static VAr compensators (SVCs) placement, while active power control is performed through flexible loads, particularly shiftable and interruptible loads. The first stage of the proposed two-stage stochastic model assigns decision-making regarding calculating PV hosting capacity at different nodes, in addition to the allocation and capacity of SVCs. In the second stage, the first stage decisions are assessed to ensure the power flow constraints under various uncertainties such as daily load and stochastic PV generation. The presented model is investigated through numerical analyses on modified IEEE 15-bus and IEEE 33-bus distribution systems considering different active-reactive strategy cases. While most previous works only rely on one type of active or reactive power control strategy, this study investigates the challenges of the respective application of active and reactive power control in various modes of fundamental practices. The obtained results prove the superiority of the proposed hybrid active-reactive control strategy for enhancing PV hosting capacity compared to respective active or reactive power controls.
The COVID-19 pandemic has presented tremendous challenges to the world, one of which is the management of infectious waste generated by healthcare activities. Finding cost-efficient services with minimum threats to pu...
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The COVID-19 pandemic has presented tremendous challenges to the world, one of which is the management of infectious waste generated by healthcare activities. Finding cost-efficient services with minimum threats to public health has become a top priority. The pandemic has induced extreme uncertainties, not only in the amount of generated waste, but also in the associated service times. With this in mind, the present study develops a mixed-integer linear programming (MILP) model for the location-routing problem with time windows (LRPTW). To handle the uncertainty in the amount of generated waste, three scenarios are defined respectively reflecting different severity levels of a pandemic. Furthermore, chance constraints are applied to deal with the variation of the service times at small generation nodes, and time windows at the transfer facilities. The complexity of the resulting mathematical model motivated the application of a branch-and-price (B&P) algorithm along with an -constraint technique. A case study of the situation of Wuhan, China, during the initial COVID-19 outbreak is employed to examine the performance and applicability of the proposed model. Our numerical tests indicate that the B&P algorithm outperforms CPLEX in the computational times by more than 83% in small-sized problem instances and reduces the gaps by at least 70% in large-scale ones. Through a comparison with the current and deterministic systems, our proposed stochastic system can timely adjust itself to fulfill nearly four times the demand of other systems in an extreme pandemic scenario, while maintaining a cost-efficient operation with no outbreak.
As one of the important renewable energy sources (RESs), the integration of wind energy into the electric grid is growing fast. This higher penetration level of wind power calls for requirements for reinforcing the ex...
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As one of the important renewable energy sources (RESs), the integration of wind energy into the electric grid is growing fast. This higher penetration level of wind power calls for requirements for reinforcing the existing transmission network to reduce wind power curtailment. In this context, this research focuses on developing a mathematical methodology for joint transmission network and wind power investment problem under a centralized approach. Unlike the existing models, where the objective function to be minimized is the overall cost, the objective function of this work is different. It is defined as the ratio of the total cost to the total wind power generation. The definition of this objective function allows the operator to minimize the total cost while maximizing the wind power output from wind farms. The convex AC power flow is utilized to model the power flow equations. The proposed investment model is mixed-integer quasi-convex programming (MIQCP) that is converted into a mixed-integer convex programming (MICP) problem. The numerical study indicates that the resulting MICP problem is computationally efficient, making it suitable for a realistic electric grid. In addition, it will promote the wind power output of wind farms.
Decision-making processes often involve uncertainty. A common approach for modeling uncertain scenario-based decision-making progressions is through multi-stage stochastic programming. The size of optimization problem...
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Decision-making processes often involve uncertainty. A common approach for modeling uncertain scenario-based decision-making progressions is through multi-stage stochastic programming. The size of optimization problems derived from multi-stage stochastic programs is frequently too large to be addressed by a direct solution technique. This is due to the size of the optimization problems, which grows exponentially as the number of scenarios and stages increases. To cope up with this computational difficulty, solution schemes turn to decomposition methods for defining smaller and easier to solve equivalent sub-problems, or through using scenario-reduction techniques. In our study a new methodology is proposed, titled Limited Multi-stage stochastic programming (LMSP), in which the number of decision variables at each stage remains constant and thus the total number of decision variables increases only linearly as the number of scenarios and stages grows. The LMSP employs a decision-clustering framework, which utilizes the optimal decisions obtained by solving a set of deterministic optimization problems to identify decision nodes, which have similar decisions. These nodes are clustered into a preselected number of clusters, where decisions are made for each cluster instead of for each individual decision node. The methodology is demonstrated on a multi-stage water supply system operation problem, which is optimized for flow and salinity decisions. LMSP performance is compared to that of classical multi-stage stochastic programming (MSP) method. (c) 2012 Elsevier Ltd. All rights reserved.
stochastic network-constrained unit commitment (S-NCUC) can be used to manage the uncertainty of an increasing penetration level of renewable energy effectively. However, the drawbacks of the progressive hedging algor...
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Low-probability but high-impact extreme events, such as floods, earthquakes, hurricanes, etc., could threaten the security of a multi-energy system, especially on the distribution level, and cause severe energy supply...
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Low-probability but high-impact extreme events, such as floods, earthquakes, hurricanes, etc., could threaten the security of a multi-energy system, especially on the distribution level, and cause severe energy supply outages. In this paper, a coordinated restoration method is presented for the renewable energy-integrated multi-energy distribution system (MDS) with several coupling points to coordinate the preparation and load recovery stages after the extreme event. First, the MDS restoration is comprehensively modeled with coupled power and thermal network constraints. Especially, the thermal inertia, which is in the form of pipe storage and thermal demand response of smart buildings to serve as a buffer when the source fails, is fully utilized to reduce the energy supply cost after disasters. Secondly, both preparation and load recovery stage measures are employed to facilitate efficient and reliable system restoration. Furthermore, multiple uncertainties from the renewable generation and power demands in the MDS restoration are dealt with via a risk-averse two-stage stochastic programming approach. Finally, simulation results validate the effectiveness of our method and its superiority over the traditional restoration methods.
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