This study investigates the potential of hydrogen as an energy carrier to store seasonal energy from wind power in a remote off-grid underground mine located in the Northwest Territories, Canada. The energy demands to...
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This study investigates the potential of hydrogen as an energy carrier to store seasonal energy from wind power in a remote off-grid underground mine located in the Northwest Territories, Canada. The energy demands to be satisfied by the Energy Supply System (ESS) were electricity, heating, and cooling. Diesel imports and local wind were the energy utilities available. An optimization model of the mine's ESS was formulated using mixedintegerlinearprogramming to search for cost-effective and sustainable energy supply solutions. The objective function to be minimized was the total cost of the ESS (investment plus operation costs). Several optimization scenarios were investigated in a sensitivity analysis, varying the time discretization (12 typical days v. 365 days), and the amount of conventional energy sources (i.e., diesel) available. The analysis could be extended to include other demands, such as mobile work demand and related conversion technologies, i.e.,hydrogen-fueled mobile equipment. For the case study considered, results demonstrated that it is technically feasible to meet the demands of a remote mine using a local renewable energy resource exclusively. However, the cost, size, and complexity of the ESS make such an option, in general, unattractive in comparison with a fossil fuel-based system. (C) 2020 Elsevier Ltd. All rights reserved.
This paper presents a mathematical model for the energy management (EM) problem of a microgrid (MG) by means of a mixedintegerlinearprogramming approach. In the EM problem, the objective is to determine a generatio...
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This paper presents a mathematical model for the energy management (EM) problem of a microgrid (MG) by means of a mixedintegerlinearprogramming approach. In the EM problem, the objective is to determine a generation and a controllable load demand policy that minimises, over a planning horizon, the operation cost subject to economical and technical constraints. We propose a detail modelling for microturbines (MTs) and fuel cells (FCs), where the constraints associated with such factors as the ramps, minimum up and downtime, and generation limits, represent various peculiarities that have not been adequately considered in literature. The proposed model also considers a detailed representation of critical, reschedulable and curtailable loads, which are important aspects in the MG concept. To analyse the proposed modelling, a MG is used along with a MT, a FC, a battery bank, wind and photovoltaic generators connected to the main grid. The results indicate that the model is adequate for the MG EM. (C) 2014 Elsevier B.V. All rights reserved.
The behavior of timed continuous Petri nets (TCPN) can be ruled by linear equations during certain time elapses (IB-states), but changes in the marking and conflict solving policies make nonlinear the complete computa...
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The behavior of timed continuous Petri nets (TCPN) can be ruled by linear equations during certain time elapses (IB-states), but changes in the marking and conflict solving policies make nonlinear the complete computation of the behavior. In this paper a global characterization of the switching behavior of TCPN through mixed linear integer programming (MLIP) is presented. The contribution is an analytical technique to compute the evolution graph of a TCPN, which allows deriving MLIP problems from TCPN models including cycles and structural conflicts;conflict resolution policies by priorities and sharing are considered. (C) 2015 Elsevier Ltd. All rights reserved.
In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several us...
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In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several users, and a single eavesdropper that intends to wiretap the transmitted message within each OFDMA subchannel. By taking into consideration the existence of the eavesdropper, the base station aims to assign subchannels and allocate the available power in order to optimize the max-min fairness criterion over the users' secrecy rate. The considered problem is a mixedinteger nonlinear program. For a fixed subchannel assignment, the optimal power allocation is obtained by developing an algorithm of polynomial computational complexity. In the general case, the problem is investigated from two different perspectives due to its combinatorial nature. In the first, the number of users is equal or higher than the number of subchannels, whereas in the second, the number of users is less than the number of subchannels. In the first case, we provide the optimal solution in polynomial time by transforming the original problem into an assignment one for which there are polynomial time algorithms. In the second case, the secrecy rate formula is linearly approximated and the problem is transformed to a mixedintegerlinear program, which is solved by a branch-and-bound algorithm. Moreover, optimality is discussed for two particular cases where the available power tends to infinity and zero, respectively. Based on the resulting insights, three heuristic schemes of polynomial complexity are proposed, offering a better balance between performance and complexity. Simulation results demonstrate that each one of these schemes achieves its highest performance at a different power regime of the system.
Small-scale distributed photovoltaic (PV) generation, in which PV panels are installed on residential customers' rooftops, has been envisaged as an approach to increase renewable energy participation. In this pape...
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ISBN:
(纸本)9781509033591
Small-scale distributed photovoltaic (PV) generation, in which PV panels are installed on residential customers' rooftops, has been envisaged as an approach to increase renewable energy participation. In this paper, we have presented a method to determine the economic benefits obtained by residential customers who can freely purchase and sell electricity from an open electricity market, when PV panels are installed on their rooftops with and without support from electrical storage. By using our method, the number of PV panels that can be optimally installed on rooftops for maximum economic benefits can be determined. Further, since PV costs are expected to decrease over the next decade, we have extended the methodology to model progressive piecemeal installations of PV panels over many years. We applied our methodology to the case of a Finnish customer participating in the Nordic electricity market. Although installing PV panels is not beneficial for Finnish residential customers today considering the current LCOE prices, customers obtain longterm benefits from using PV panels, and these benefits improve with the inclusion of batteries.
Nowadays, Supply Chain success and competitiveness heavily depend on the integration of its components and adaptability to deal with a changing environment. This article suggests the integration of design and manageme...
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Nowadays, Supply Chain success and competitiveness heavily depend on the integration of its components and adaptability to deal with a changing environment. This article suggests the integration of design and management of a Supply Chain from an outcome-driven perspective. We propose a two-phase decision-making support methodology: first suppliers are pre-screened by solving a multi criteria sorting problem, and then a design and management plan is generated by solving a mixedintegerlinearprogramming Model. Experimentally we showed that the proposed methodology can efficiently solve to optimality the most popular benchmark instances published in previous paper moreover our model also includes problem characteristics that have not been addressed together in previous published papers.
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