Results 1 - 10 of 1722
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[en] The flow of a commodity is modelled as a quasi-thermodynamic irreversible process. The flow is treated not as a mass quantity, but more like a transient energy quantity. A commodity is thus considered an artefact that depends on whether it resides or is stored within the system or is in transit across the system boundary to the surroundings. This allows the use of the fundamental laws of thermodynamics and brings further insight into the process of commodity diffusion. The methods of irreversible thermodynamics are also considered and a coupling relation between commodity price and quality is derived. (author)
[en] The Virtual Power Plant (VPP) has gained an increasing interest over the last few years. A VPP is a flexible representation of a portfolio of Distributed Energy Resources (DER: distributed generation, demand response and electricity storage). One of the key activities of a VPP is the delivery of (near-)real-time balancing services. In order to operate such a (near-)real-time coordination activity optimally, the VPP needs to maintain a dynamic merit-order list of all DER participating in the VPP. In order to make optimal decisions based on this list, the merit order needs to be based on the true marginal cost (or marginal benefit in case of demand response) of the individual DER units. The marginal electricity costs of most types of DER are highly dependent on local context and, hence, change over time. From analysis of the short-term bid strategies of various DER units, the existence of a bid strategy spectrum becomes clear. On one end of the spectrum, bidding strategies are based straightforwardly on true marginal cost or benefit. Further along the spectrum, optimal bidding strategies become less dependent on marginal cost levels and more on the price dynamics in the (VPP) market context. These results are relevant for VPP operations both from business and technical perspectives.
[en] A supply chain model comprising of one manufacturer and two retailers have been discussed in the proposed model, where the manufacturer acts as leader. It has been assumed that both the retailers offer service facilities to the customers. The optimal pricing strategy of the members of the supply chain have been derived analytically in three situations, namely, Cournot situation, Collusion situation and Stackelberg situation. In Cournot situation, both the retailers set independently the unit selling prices on the wholesale price set by the manufacturer. In Collusion situation, both the retailers agree to set their unit selling prices which maximizes the total profit of the retailers. In case of Stackelberg situation, one of the two retailers acts as leader and the other retailer is the follower. It has been observed that in Collusion situation, the retailer-1 incurs highest profit, whereas, in Stackelberg situation, the retailer-2 achieves highest profit. In the Collusion situation, the retailer-2 can charge higher selling price, but due to more service expenses, the corresponding profit of the retailer-2 is lower than that of retailer-1. The model is solved analytically and the solution has been illustrated with the help of two numerical examples.
[en] Wholesale marginal electricity prices are being used in several actual competitive generation markets worldwide, both to remunerate generators and to charge consumption. These prices must account not only for energy, but also for guarantee of supply in the long and the short term. This paper: (a) provides a sound conceptual and quantitative foundation for wholesale pricing based on generation services, where any existing restrictions in operation or planning in real power markets are accounted for, (b) clearly establishes the relationship between short term marginal costs, long term marginal costs and optimal wholesale electricity prices, and (c) identifies the reasons for mismatches in cost recovery with marginal generation prices. The theoretical results are verified with a detailed realistic power system model
[en] Congestion cost allocation is a very important topic in congestion management. Allocation methods based on the Aumann-Shapley value use the discrete numerical integration method, which needs to solve the incremented OPF solution many times, and as such it is not suitable for practical application to large-scale systems. The optimal solution and its sensitivity change tendency during congestion removal using a DC optimal power flow (OPF) process is analysed. A simple continuous integration method based on the sensitivity is proposed for the congestion cost allocation. The proposed sensitivity analysis method needs a smaller computation time than the method based on using the quadratic method and inner point iteration. The proposed congestion cost allocation method uses a continuous integration method rather than discrete numerical integration. The method does not need to solve the incremented OPF solutions; which allows it use in large-scale systems. The method can also be used for AC OPF congestion management. (author)
[en] Successful real-time electricity pricing depends firstly upon consumers' willingness to subscribe to such terms and, secondly, on their ability to curb consumption levels. The present paper addresses both issues by considering consumers differentiated by their electricity saving costs, half of whom resist saving electricity. We demonstrate that when consumers are free to adopt real-time prices, producers prefer charging inefficient prices and, in so doing, discriminate against that portion of the consumer population which faces no saving costs. We also find that efficient marginal cost pricing is feasible, but is incompatible with mass adoption of real-time prices. - Highlights: • We model consumers switching from uniform to real-time electricity pricing (RTP). • Half the consumer population is pro-RTP and half resists saving electricity. • Efficient RTP is feasible but is incompatible with mass adoption
[en] Highlights: • We analyze Cournot oligopolies with heterogeneous firms of generic size. • Rational and naive players are considered. • Stability with respect to oligopoly composition is studied. • In some settings, increasing the rational firms fraction introduces instability. - Abstract: In this paper we study oligopolies of generic size consisting of heterogeneous firms, which adopt best response adjustment mechanisms with either perfect foresight (rational firms) or static expectations (naive firms). Assuming an isoelastic demand function and possibly different marginal costs for the two groups of firms, we focus on the local stability of the Nash equilibrium. We show that, with respect to the oligopoly composition, described in terms of the fraction of rational firms, different scenarios are possible. We find that a high rationality degree may not always guarantee stability, in particular when rational firms have sufficiently larger marginal costs. In fact, in this situation, increasing the fraction of rational firms can even introduce instability. Besides the usual scenarios in which replacing some naive firms with rational ones leads to a stabilization of (or at least keeps unchanged) the dynamics, we provide a family of situations, characterized by costs ratio favorable to naive firms, in which equilibrium loses its stability when naive firms are replaced by rational ones. The results we present are both analytical and simulative.
[en] In many countries, electricity demand increases very steeply during the morning hours, and decreases steeply during the evening hours. A steep change in electricity demand incurs considerable costs for ramping up and down electric power equipment, and raises the possibility of a large-scale blackout. This paper gives new insights into classical real-time pricing (RTP) by considering the case in which demand changes very steeply. We generalize the concept of the ramping costs, and derive an extended form of RTP that achieves the optimal rate of change in quantity demanded by explicitly taking the ramping costs into account. Under the optimal pricing policy, the prices are dramatically reduced during the period corresponding to the lower end of the slope of the load curve. In contrast, the prices are dramatically raised during the period corresponding to the upper end of the slope of the load curve. As a result, the steepness of the load curve will be remarkably controlled, which will reduce both the ramping costs and the possibility of a large-scale blackout. (author)
[en] There is general agreement amongst economists and ecologists that transportation is an important contributor to greenhouse gas emissions. Typical proposals to reduce the demand for transportation, and consequently emissions, focus on imposing a fuel tax or a direct fee on vehicles. This paper outlines the method and advantages of treating the environmental risk as additional pseudo coverage rated under existing property and liability motor vehicle insurance systems. (author)
[en] The paper presents an intuitively logical split between: (a) embedded, (b) operating, and (c) expansion cost based pricing and methodologies for implementation, for transmission services. A conceptually straightforward mechanism for the equitable allocation of transmission network embedded cost recovery based on capacity-use and reliability benefit is proposed, expansion cost is charged on a long-run marginal cost basis and finally, operating cost recovery is based on short-run marginal pricing. This is followed by co-ordinating these alternatives and integrating the pricing mechanisms to achieve appropriate price signals for bulk power users of transmission systems. (author)