Network-constrained models of liberalized electricity markets: the devil is in the details

Numerical models for electricity markets are frequently used to inform and support decisions. How robust are the results? Three research groups used the same, realistic data set for generators, demand and transmission network as input for their numerical models. The results coincide when predicting competitive market results. In the strategic case in which large generators can exercise market power, the predicted prices differed significantly. The results are highly sensitive to assumptions about market design, timing of the market and assumptions about constraints on the rationality of generators. Given the same assumptions the results coincide. We provide a checklist for users to understand the implications of different modelling assumptions

Network-constrained models of liberalized electricity markets: the devil is in the details

Numerical models for electricity markets are frequently used to inform and support decisions. How robust are the results? Three research groups used the same, realistic data set for generators, demand and transmission network as input for their numerical models. The results coincide when predicting competitive market results. In the strategic case in which large generators can exercise market power, the predicted prices differed significantly. The results are highly sensitive to assumptions about market design, timing of the market and assumptions about constraints on the rationality of generators. Given the same assumptions the results coincide. We provide a checklist for users to understand the implications of different modelling assumptions.Market power, Electricity, Networks, Numeric models, Model comparison

Supply function equilibria in transportation networks

Transport constraints limit competition and arbitrageurs' possibilities of exploiting price differences between commodities in neighbouring markets. We analyze a transportation network where oligopoly producers compete with supply functions under uncertain demand, as in wholesale electricity markets. For symmetric networks with a radial structure, we show that existence of symmetric supply function equilibria (SFE) is ensured if demand shocks are sufficiently evenly distributed. We can explicitly solve for them for uniform multi-dimensional nodal demand shocks

Modeling and Control of High-Voltage Direct-Current Transmission Systems: From Theory to Practice and Back

The problem of modeling and control of multi-terminal high-voltage direct-current transmission systems is addressed in this paper, which contains five main contributions. First, to propose a unified, physically motivated, modeling framework - based on port-Hamiltonian representations - of the various network topologies used in this application. Second, to prove that the system can be globally asymptotically stabilized with a decentralized PI control, that exploits its passivity properties. Close connections between the proposed PI and the popular Akagi's PQ instantaneous power method are also established. Third, to reveal the transient performance limitations of the proposed controller that, interestingly, is shown to be intrinsic to PI passivity-based control. Fourth, motivated by the latter, an outer-loop that overcomes the aforementioned limitations is proposed. The performance limitation of the PI, and its drastic improvement using outer-loop controls, are verified via simulations on a three-terminals benchmark example. A final contribution is a novel formulation of the power flow equations for the centralized references calculation

Congestion management in electricity networks

Wholesale electricity markets use different market designs to handle congestion in the transmission network. We compare nodal, zonal and discriminatory pricing in general networks with transmission constraints and loop flows. We conclude that in large games with many producers who are allowed to participate in the real-time market the three market designs result in the same efficient dispatch. However, zonal pricing with counter-trading results in additional payments to producers in exportconstrained nodes

Congestion management in electricity networks: Nodal, zonal and discriminatory pricing

Wholesale electricity markets use different market designs to handle congestion in the transmission network. We compare nodal, zonal and discriminatory pricing in general networks with transmission constraints and loop flows. We conclude that in large games with many producers who are allowed to participate in the real-time market the three market designs result in the same efficient dispatch. However, zonal pricing with counter-trading results in additional payments to producers in exportconstrained nodes.discriminatory pricin

Optimal Transmission Regulation in an Integrated Energy Market

The capacity of the transmission network determines the extent of integration of a multinational energy market. Cross-border externalities render coordination of network maintenance and investments across countries valuable. Is it then optimal to collect powers in the hands of a single regulator? Should a common system operator manage the entire network? I show that optimal network structure depends on (i ) how the common regulator would balance the interests of the different member states; (ii ) how the gains from market integration vary across countries; (iii ) network characteristics (substitutability versus complementarity); and (iv ) the social cost of operator rent.Multi-national Energy Market; Transmission; Supranational Regulation; System Operation; Multi-contracting

Supply Function Equilibrium in Networked Electricity Markets

We study deregulated power markets with strategic power suppliers. In deregulated markets, each supplier submits its supply function (i.e., the amount of electricity it is willing to produce at various prices) to the independent system operator (ISO), who based on the submitted supply functions, dispatches the suppliers to clear the market with minimal total generation cost. If all suppliers reported their true marginal cost functions as supply functions, the market outcome would be efficient (i.e., the total generation cost is minimized). However, when suppliers are strategic and aim to maximize their own profits, the reported supply functions are not necessarily the true marginal cost functions, and the resulting market outcome may be inefficient. The efficiency loss depends crucially on the topology of the underlying transmission network. This paper provides an analytical upper bound of the efficiency loss due to strategic suppliers, and proves that the bound is tight under a large class of transmission networks (i.e., weakly cyclic networks). Our upper bound sheds light on how the efficiency loss depends on the transmission network topology (e.g., the degrees of nodes, the admittances and flow limits of transmission lines).Comment: 13 pages, 6 figure

The stability of downtown parking and traffic congestion

Consider a transport facility in steady state that is operating at maximum throughput. How does it respond to a once-and-for-all increase in demand? The trip price must increase to ration the increased demand, but how? These questions have been the subject of a debate in transport economic theory dating back to Walters’ classic paper (1961). The current wisdom is that the facility continues to operate at full capacity, with travel at reduced velocity and/or increased queuing serving to increase the trip price. This paper analyzes the transient dynamics and stability of steady states for a spatially uniform road network with on-street parking, and finds in this context that the increase in demand may cause operation at reduced throughput