That’s Not Fair: Tariff Structures for Electric Utilities with Rooftop Solar

Problem definition: Utility regulators are grappling to devise compensation schemes for customers who sell rooftop solar generation back to the grid, balancing environmental interests and the financial interests of utilities, solar system installers, and retail customers. This is difficult: Regulatory changes made in Nevada in 2015 to protect Nevada’s utility induced SolarCity, the market leader in solar systems, to suspend local operations. We show that the choice of utility tariff structure is crucial to achieving socially desirable objectives. Academic/practical relevance: It is important for regulators to understand how tariff structure interacts with social objectives. This has implications for consumers, regulators, and industry. Methodology: We use a sequential game to analyze the regulator’s social welfare maximization problem in a market with a regulated utility; an unregulated, price-setting, profit-maximizing solar system installer; and customers who endogenously determine whether to adopt solar or not, based on utility tariffs, solar prices, and their heterogeneous usage profiles and generation potentials. Results: We illustrate that the effectiveness of tariff structures is not governed simply by the number of free tariff parameters, but by the functions these parameters serve. In particular, an effective tariff must discriminate among customer usage tiers and between customers with and without rooftop solar to achieve socially desirable outcomes. We present a tariff structure with these two characteristics and show how it can be implemented as a simple buy-all, sell-all tariff while retaining its favorable properties. We illustrate our findings numerically using data from Nevada and New Mexico, two states grappling with this issue. Managerial implications: Many utilities in the United States operate tariff structures that are missing at least one of the two identified features. Regulators must overhaul these tariff structures to adequately safeguard all stakeholders

Optimal Structural Results for Assemble-to-Order Generalized M-Systmes

Cataloged from PDF version of article.We consider an assemble-to-order generalized M-system with multiple components and multiple products, batch ordering of components, random lead times, and lost sales. We model the system as an in nite-horizon Markov decision process and seek an optimal control policy, which speci es when a batch of components should be produced and whether an arriving demand for each product should be satis ed. To facilitate our analysis, we introduce new functional characterizations for convexity and submodularity with respect to certain non-unitary directions. These help us characterize optimal inventory replenishment and allocation policies under a mild condition on component batch sizes via a new type of policy: lattice-dependent base-stock and lattice-dependent rationing

Intrinsic Metastabilities in the Charge Configuration of a Double Quantum Dot

We report a thermally activated metastability in a GaAs double quantum dot exhibiting real-time charge switching in diamond shaped regions of the charge stability diagram. Accidental charge traps and sensor back action are excluded as the origin of the switching. We present an extension of the canonical double dot theory based on an intrinsic, thermal electron exchange process through the reservoirs, giving excellent agreement with the experiment. The electron spin is randomized by the exchange process, thus facilitating fast, gate-controlled spin initialization. At the same time, this process sets an intrinsic upper limit to the spin relaxation time.Comment: 4 pages, 5 figures (color

TLR ligand-induced podosome disassembly in dendritic cells is ADAM17 dependent

Toll-like receptor (TLR) signaling induces a rapid reorganization of the actin cytoskeleton in cultured mouse dendritic cells (DC), leading to enhanced antigen endocytosis and a concomitant loss of filamentous actin–rich podosomes. We show that as podosomes are lost, TLR signaling induces prominent focal contacts and a transient reduction in DC migratory capacity in vitro. We further show that podosomes in mouse DC are foci of pronounced gelatinase activity, dependent on the enzyme membrane type I matrix metalloprotease (MT1-MMP), and that DC transiently lose the ability to degrade the extracellular matrix after TLR signaling. Surprisingly, MMP inhibitors block TLR signaling–induced podosome disassembly, although stimulated endocytosis is unaffected, which demonstrates that the two phenomena are not obligatorily coupled. Podosome disassembly caused by TLR signaling occurs normally in DC lacking MT1-MMP, and instead requires the tumor necrosis factor α–converting enzyme ADAM17 (a disintegrin and metalloprotease 17), which demonstrates a novel role for this “sheddase” in regulating an actin-based structure

Real-time delay announcement under competition

Internet-based technology enables firms to disseminate real-time delay information to delay-sensitive customers. We study how such delay announcements impact service providers in a competitive environment with two service providers who compete for market share. We model the service providers' strategies based on an endogenous timing game, investigating strategies that emerge in equilibrium. We determine the service providers' market shares under the various game outcomes by analyzing continuous-time Markov chains, which capture customers' joining decisions, and by developing a novel computational technique to analyze the intractable asymmetric Join-the-Shortest Queue system, providing bounds on the market shares. We find that only the lower capacity service provider announces its real-time delay under intermediate system loads and highly imbalanced capacities. However, for most parameter settings, the mere presence of a competitor induces both providers to announce delays in equilibrium, leaving customers better off on average. We relate our findings to the single-provider delay announcement literature by discussing the impact of competition on service providers, delay announcement technology firms, and customers

PROBLEMS IN THE DETERMINATION OF EFFECTIVE DIFFUSION COEFFICIENTS OF GASES AND LIQUIDS USING THE UP-TAKE TECHNIQUE

Diffusion processes play an important role in many areas of science and technology. Since pore diffusion processes strongly depend on the pore texture of the porous solid, a desired value of an effective diffusion coefficient, D, has to be determined experimentally. Although, several measuring techniques have been described in the open literature, only a few of them can be used to set up a routine procedure. One of these methods is the so-called Up-Take Technique. The evaluation of the experimental data in this case, however, can lead to difficulties which will be discussed in detail