Network Access in the Deregulated European Electricity Market: Negotiated Third-Party Access vs. Single Buyer

The question of third-party access to the networks has become central to the debate around the liberalisation of the European electricity markets due to the natural monopoly characteristic of the transmission network. The European Union?s electricity directive provides three institutional options for the organisation of network access: the single buyer procedure, the negotiated third-party access and the regulated third-party access. This paper analyses these regimes in a framework of an imperfect decision-making regulation authority which can commit errors when supervising the transmission tariffs. It will be shown that the equivalence of the systems required in the directive is usually not achieved. In addition, conditions for deciding between the three systems are derived under social welfare considerations. -- Bei der Liberalisierung der europäischen Elektrizitätsmärkte ist wegen der natürlichen Monopoleigenschaft des Übertragungsnetzes die Frage des Netzzugangs Dritter von zentraler Bedeutung. Die EU-Stromrichtline bietet drei institutionelle Alternativen zur Organisation des Netzzugangs an: Das Alleinkäufersystem, den regulierten und den verhandelten Netzzugang. Dieser Beitrag untersucht diese drei Netzzugangsregime im Kontext einer fehlerhaft entscheidenden Aufsichtsbehörde. Er kommt zu dem Ergebnis, daß die in der Richtlinie postulierte Ergebnisäquivalenz der Systeme in der Regel nicht erreicht wird. Darüberhinaus werden Kriterien für die Entscheidung zwischen den Alternativen unter Effizenzgesichtspunkten hergeleitet.Electricity Industry,Network Access,Imperfect Regulation Agency

Characterization of Time-Consistent Sets of Measures in Finite Trees

In this paper we give an alternative characterization for time-consistent sets of measures in a discrete setting. For each measure p in a time-consistent set P we get a distinct set of predictable processes which in return describe the p uniquely. This implies we get a one-to-one correspondence between time-consistent sets of measures and sets of predictable processes with specifc features.Multiple Priors, Time-Consistency, Ambiguity, Uncertainty Aversion

Bioprocessing: Prospects for space electrophoresis

The basic principles of electrophoresis are reviewed in light of its past contributions to biology and medicine. The near-zero gravity environment of orbiting spacecraft may present some unique advantages for a variety of processes, by abolishing the major source of convection in fluids. As the ground-based development of electrophoresis was heavily influenced by the need to circumvent the effects of gravity, this process should be a prime candidate for space operation. Nevertheless, while a space facility for electrophoresis may overcome the limitations imposed by gravity, it will not necessarily overcome all problems inherent in electrophoresis. These are, mainly, electroosmosis and the dissipation of the heat generated by the electric field. The NASA program has already led to excellent coatings to prevent electroosmosis, while the need for heat dissipation will continue to impose limits on the actual size of equipment. It is also not excluded that, once the dominant force of gravity is eliminated, disturbances in fluid stability may originate from weaker forces, such as surface tension

Hormone purification by isoelectric focusing in space

The objective of the program was the definition and development of optimal methods for electrophoretic separations in microgravity. The approach is based on a triad consisting of ground based experiments, mathematical modeling and experiments in microgravity. Zone electrophoresis is a rate process, where separation is achieved in uniform buffers on the basis of differences in electrophoretic mobilities. Optimization and modeling of continuous flow electrophoresis mainly concern the hydrodynamics of the flow process, including gravity dependent fluid convection due to density gradients and gravity independent electroosmosis. Optimization of focusing requires a more complex model describing the molecular transport processes involved in electrophoresis of interacting systems. Three different focusing instruments were designed, embodying novel principles of fluid stabilization. Fluid stability was achieved by: (1) flow streamlining by means of membrane elements in combination with rapid fluid recycling; (2) apparatus rotation in combination with said membrane elements; and (3) shear stress induced by rapid recycling through a narrow gap channel

Density functional theory of electrowetting

The phenomenon of electrowetting, i.e., the dependence of the macroscopic contact angle of a fluid on the electrostatic potential of the substrate, is analyzed in terms of the density functional theory of wetting. It is shown that electrowetting is not an electrocapillarity effect, i.e., it cannot be consistently understood in terms of the variation of the substrate-fluid interfacial tension with the electrostatic substrate potential, but it is related to the depth of the effective interface potential. The key feature, which has been overlooked so far and which occurs naturally in the density functional approach is the structural change of a fluid if it is brought into contact with another fluid. These structural changes occur in the present context as the formation of finite films of one fluid phase in between the substrate and the bulk of the other fluid phase. The non-vanishing Donnan potentials (Galvani potential differences) across such film-bulk fluid interfaces, which generically occur due to an unequal partitioning of ions as a result of differences of solubility contrasts, lead to correction terms in the electrowetting equation, which become relevant for sufficiently small substrate potentials. Whereas the present density functional approach confirms the commonly used electrocapillarity-based electrowetting equation as a good approximation for the cases of metallic electrodes or electrodes coated with a hydrophobic dielectric in contact with an electrolyte solution and an ion-free oil, a significantly reduced tendency for electrowetting is predicted for electrodes coated with a dielectric which is hydrophilic or which is in contact with two immiscible electrolyte solutions.Comment: Submitte

Controlling the interfacial and bulk concentrations of spontaneously charged colloids in non-polar media

Stabilization and dispersion of electrical charge by colloids in non-polar media, such as nano-particles or inverse micelles, is significant for a variety of chemical and technological applications, ranging from drug delivery to e-ink. Many applications require knowledge about concentrations near the solid|liquid interface and the bulk, particularly in media where colloids exhibit spontaneous charging properties. By modification of the mean field equations to include the finite size effects that are typical in concentrated electrolytes along with disproportionation kinetics, and by considering high potentials, it is possible to evaluate the width of the condensed double layers near planar electrodes and the bulk concentrations of colloids at steady state. These quantities also provide an estimate of the minimum initial colloid concentration that is required to support electroneutrality in the dispersion bulk, and thus provide insights into the quasi-steady state currents that have been observed in inverse micellar media.Comment: 13 pages, 5 figure

Opportunities for space bioprocessing

The need for improved purification technologies, the role of electrophoresis, and isoelectric focusing are discussed in the context of space bioprocessing