Regulated electricity networks, investment mistakes in retrospect and stranded assets under uncertainty

From 2004 to 2018 the Regulatory Asset Base (RAB) of electricity networks across Australia’s National Electricity Market tripled in value, from $32 billion to$93 billion. The run-up in the capital stock was driven by forecast demand growth and a tightening of reliability standards. But demand contracted from 2010-2015. With a rising RAB, contracting demand and a regulated revenue constraint, an adverse cycle of sharply rising tariffs and falling demand appeared to be emerging. Some networks were characterised by significant investment mistakes in retrospect, and perhaps unsurprisingly, various consumer groups and regulatory bodies argued assets should be stranded or written-off completely and network tariffs reduced. From 2015-2018, energy demand increased once again. In this article we present a method for dealing with stranded assets under uncertainty; rather than permanently stranding assets that fail a used and useful test, we reorganise the financial and economic affairs of a template network utility and “Park” excess capacity, issue credit-wrapped bonds to temporarily finance the stranded capital stock, then re-test the Parked Assets at the end of each five-year regulatory determination. Parked Assets can then be “Un-Parked” and returned-to-service in line with connections growth, load growth, or both. The most interesting result is the immediate reduction in network tariffs, and a more stable trajectory under our generalised assumptions

Modulation of a surface plasmon-polariton resonance by sub-terahertz diffracted coherent phonons

Coherent sub-THz phonons incident on a gold grating that is deposited on a dielectric substrate undergo diffraction and thereby induce an alteration of the surface plasmon-polariton resonance. This results in efficient high-frequency modulation (up to 110 GHz) of the structure's reflectivity for visible light in the vicinity of the plasmon-polariton resonance. High modulation efficiency is achieved by designing a periodic nanostructure which provides both plasmon-polariton and phonon resonances. Our theoretical analysis shows that the dynamical alteration of the plasmon-polariton resonance is governed by modulation of the slit widths within the grating at the frequencies of higher-order phonon resonances.Comment: 5 pages, 4 figure

Nominally forbidden transitions in the interband optical spectrum of quantum dots

We calculate the excitonic optical absorption spectra of (In,Ga)As/GaAs self-assembled quantum dots by adopting an atomistic pseudopotential approach to the single-particle problem followed by a configuration-interaction approach to the many-body problem. We find three types of allowed transitions that would be naively expected to be forbidden. (i) Transitions that are parity forbidden in simple effective mass models with infinite confining wells (e.g. 1S-2S, 1P-2P) but are possible by finite band-offsets and orbital-mixing effects; (ii) light-hole--to--conduction transitions, enabled by the confinement of light-hole states; and (iii) transitions that show and enhanced intensity due to electron-hole configuration mixing with allowed transitions. We compare these predictions with results of 8-band k.p calculations as well as recent spectroscopic data. Transitions in (i) and (ii) explain recently observed satellites of the allowed P-P transitions.Comment: Version published in Phys. Rev.

Semianalytical Structural Analysis Based on Combined Application of Finite Element Method and Discrete-continual Finite Element Method Part 3: Plate Analysis

AbstractThis paper is devoted to so-called semianalytical plate analysis, based on combined application of finite element method (FEM) [1,2] and discrete-continual finite element method (DCFEM) [3–11]. Kirchhoff model is under consideration. In accordance with the method of extended domain, the given domain is embordered by extended one. The field of application of DCFEM comprises structures with regular (constant or piecewise constant) physical and geometrical parameters in some dimension (“basic” dimension). DCFEM presupposes finite element mesh approximation for non-basic dimension of extended domain while in the basic dimension problem remains continual. Corresponding discrete and discrete-continual approximation models for subdomains and coupled multilevel approximation model for extended domain are under consideration. Brief information about software and verification sample are presented as well

Nonequilibrium nuclear-electron spin dynamics in semiconductor quantum dots

We study the spin dynamics in charged quantum dots in the situation where the resident electron is coupled to only about 200 nuclear spins and where the electron spin splitting induced by the Overhauser field does not exceed markedly the spectral broadening. The formation of a dynamical nuclear polarization as well as its subsequent decay by the dipole-dipole interaction is directly resolved in time. Because not limited by intrinsic nonlinearities, almost complete nuclear polarization is achieved, even at elevated temperatures. The data suggest a nonequilibrium mode of nuclear polarization, distinctly different from the spin temperature concept exploited on bulk semiconductorsComment: 5 pages, 4 figure