Integrating Distributed Generation: Regulation and Trends in Three Leading Countries

We explore trends in the deployment and integration of distributed generation in Germany, Denmark and Sweden. In particular, we examine the regulation of renewable energy generation with a focus on grid access and connection mechanisms. The high rate of distributed generation penetration in these countries is the result of early support given to the expansion of renewable energy generation – mainly wind and solar - within their respective national policies. Germany and Denmark are the countries with the most sophisticated support schemes, which have shown changes over time. In terms of connections, Germany is the country with the most favourable connection regime. It provides not only priority connection but also priority use of the grid to generation units that produce electricity from renewable energy sources. Sweden guarantees equal treatment among different technologies (i.e. a non-discrimination principle) and is thus the least favourable. High connection costs have been observed, especially in Germany and Denmark. The costs of network upgrades are usually socialised across customers. The use of smart solutions combined with novel business models might allow more efficient use of the current distribution electricity infrastructure. Hence, integration issues should be taken into consideration in order to avoid expansion of distributed generation in a way that unnecessarily raises total system costs, via high connection costs

An evaluation of a local reactive power market: the case of Power Potential

This paper quantifies the benefits of introducing reactive power markets that promote the participation of distributed energy resources (DER) in a coordinated way, between the electricity system operator and the electricity distribution utilities. The contribution that DER could make by displacing conventional network assets in supplying reactive power support is evaluated in the context of a case study, the Power Potential (PP) project in Great Britain. We discuss the rising need for absorptive (leading) reactive power in the PP trial area, driven by the rapid connection of renewable generation in an area of low demand growth. A social cost benefit analysis (SCBA) is performed to quantify the net benefits, with sensitivities regarding bid prices, % of DER participation, time horizons. Price information from the PP live trial conducted between January and March 2021 is also used to evaluate the robustness of the SCBA and to estimate benefits using actual prices. Our results suggest that energy consumers could save from 8-21% of business as usual asset costs by 2050. The introduction of trial bid prices increases these savings by around 3% of business as usual asset costs out to 2050. Potential sources of additional benefits on top of those identified in the SCBA are also discussed

Where next for the electricity distribution system operator? Evidence from a survey of European DSOs and National Regulatory Authorities

This paper seeks to shed light on the nature of optimal regulation of the electricity distribution system operator (DSO) over the period to 2025 and beyond, following the implementation of the EU Clean Energy Package and its constituent parts: Electricity Regulation (EU) 2019/943 and Electricity Directive (EU) 2019/944. We conducted two parallel surveys of DSOs and their national regulatory authorities (NRAs) across 39 European countries. This produced 39 responses from DSOs and 12 responses from NRAs covering, respectively, 40% and 78% of customers in those countries. We asked both DSOs and NRAs three sets of questions related to: (1) the definition and regulation of the future system operator function of the DSO; (2) lessons learned from transmission system operator (TSO) regulation that can be translated to the DSO; and (3) the way in which regulators support the capacity of the DSO to operate and coordinate the system. Our findings are consistent with the observation that the move towards a more active role for the DSO remains work in progress for both DSOs and their NRAs, given the fact that the Clean Energy Package has only passed into European Law relatively recently and some Member States are still implementing its provisions

Geometry of Goodness-of-Fit Testing in High Dimensional Low Sample Size Modelling

We introduce a new approach to goodness-of-fit testing in the high dimensional, sparse extended multinomial context. The paper takes a computational information geometric approach, extending classical higher order asymptotic theory. We show why the Wald – equivalently, the Pearson X2 and score statistics – are unworkable in this context, but that the deviance has a simple, accurate and tractable sampling distribution even for moderate sample sizes. Issues of uniformity of asymptotic approximations across model space are discussed. A variety of important applications and extensions are noted

Localization and Capacitance Fluctuations in Disordered Au Nano-junctions

Nano-junctions, containing atomic-scale gold contacts between strongly disordered leads, exhibit different transport properties at room temperature and at low temperature. At room temperature, the nano-junctions exhibit conductance quantization effects. At low temperatures, the contacts exhibit Coulomb-Blockade. We show that the differences between the room-temperature and low temperature properties arise from the localization of electronic states in the leads. The charging energy and capacitance of the nano-junctions exhibit strong fluctuations with applied magnetic field at low temperature, as predicted theoretically.Comment: 20 pages 8 figure

First Measurement of the Neutron β\beta-Asymmetry with Ultracold Neutrons

We report the first measurement of angular correlation parameters in neutron $\beta$-decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for $\sim 30$ s in a Cu decay volume. The $\vec{\mu}_n \cdot \vec{B}$ potential of a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage (AFP) spin-flipper and enter a decay volume, situated within a 1 T, $2 \times 2\pi$ superconducting solenoidal spectrometer. We determine a value for the $\beta$-asymmetry parameter $A_0$, proportional to the angular correlation between the neutron polarization and the electron momentum, of $A_0 = -0.1138 \pm 0.0051$.Comment: 4 pages, 2 figures, 1 table, submitted to Phys. Rev. Let