Measuring persistent and transient energy efficiency in the US

The promotion of US energy efficiency policy is seen as a very important activity. Generally, the level of energy efficiency of a country or state is approximated by energy intensity, commonly calculated as the ratio of energy use to GDP. However, energy intensity is not an accurate proxy for energy efficiency given that changes in energy intensity are a function of changes in several factors including the structure of the economy, climate, efficiency in the use of resources, behaviour and technical change. The aim of this paper is to measure persistent and transient energy efficiency for the whole economy of 49 states in the US using a stochastic frontier energy demand approach. A total US energy demand frontier function is estimated using panel data for 49 states over the period 1995 to 2009 using two panel data models: the Mundlak version of the random effects model (which estimates the persistent part of the energy efficiency) and the true random effects model (which estimates the transient part of the energy efficiency). The analysis confirms that energy intensity is not a good indicator of energy efficiency, whereas, by controlling for a range of economic and other factors, the measures of energy efficiency obtained via the approach adopted here are. Moreover, the estimates show that although for some states energy intensity might give a reasonable indication of a state’s relative energy efficiency, this is not the case for all states.ISSN:1570-646XISSN:1570-647

Key findings from the core North American scenarios in the EMF34 intermodel comparison

Within Canada, Mexico or the United States, policy-making organizations are evaluating energy markets and energy trade within their own borders often by ignoring how these countries’ energy systems are integrated with each other. These analytical gaps provided the main motivation for the Energy Modeling Forum (EMF) 34 study on North American energy integration and trade. This paper compares North American results from 17 models and discusses their policy motivation. Oil and natural gas production in the three major countries are modestly sensitive to crude oil and natural gas price changes, although these elasticities are below unity. Carbon taxes displace coal and some natural gas with renewables within all three power markets. Lower natural gas prices replace coal and some renewables with natural gas within electric generation. Higher intermittent renewable penetration in the power sector displaces coal and some natural gas. A key conclusion is that much remains to be done in integrating future analyses and in sharing and improving the quality and consistency of the underlying data

Magnetic field production via the Weibel instability in interpenetrating plasma flows

Many astrophysical systems are effectively “collisionless,” that is, the mean free path for collisions between particles is much longer than the size of the system. The absence of particle collisions does not preclude shock formation, however, as shocks can be the result of plasma instabilities that generate and amplify electromagnetic fields. The magnetic fields required for shock formation mayeither be initially present, for example, in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the Weibel instability is a candidate mechanism for the generation of sufficiently strong magnetic fields to produce shocks. In experiments on the OMEGA Laser, we have demonstrated a quasi-collisionless system that is optimized for the study of the non-linear phase of Weibel instability growth. Using a proton probe to directly image electromagnetic fields, we measure Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows. The collisionality of the system is determined from coherent Thomson scattering measurements, and the data are compared to similar measurements of a fully collisionless system. The strong, persistent Weibel growth observed here serves as a diagnostic for exploring large-scale magnetic field amplification and the microphysics present in the collisional–collisionless transition

Magnetic field production via the Weibel instability in interpenetrating plasma flows

Many astrophysical systems are effectively “collisionless,” that is, the mean free path for collisions between particles is much longer than the size of the system. The absence of particle collisions does not preclude shock formation, however, as shocks can be the result of plasma instabilities that generate and amplify electromagnetic fields. The magnetic fields required for shock formation may either be initially present, for example, in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the Weibel instability is a candidate mechanism for the generation of sufficiently strong magnetic fields to produce shocks. In experiments on the OMEGA Laser, we have demonstrated a quasi-collisionless system that is optimized for the study of the non-linear phase of Weibel instability growth. Using a proton probe to directly image electromagnetic fields, we measure Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows. The collisionality of the system is determined from coherent Thomson scattering measurements, and the data are compared to similar measurements of a fully collisionless system. The strong, persistent Weibel growth observed here serves as a diagnostic for exploring large-scale magnetic field amplification and the microphysics present in the collisional-collisionless transition

A complementary understanding of residential energy demand, consumption and services

This chapter explores potential ways to implement, and benefits for policymaking of, the complementary use of two different types of modelling for analysing residential energy consumption and ethnographic research. The more traditional approach of techno-economic modelling is considered alongside agent-based modelling that incorporates both causal and intentional relationships; ethnographic approaches provide 'thick understanding' of the relationships between social and technical elements and the environment. In doing so, the chapter builds on real examples from academic-policy engagement in the EU on energy demand, consumption and services. We examine three myths of the role of modelling in policymaking and propose practical ways of employing different types of modelling in a complementary way to increase policymakers' understanding of residential energy demand, consumption and services. Finally, we make three concrete recommendations for developing future interdisciplinary work on integrating social and technical models for informing policy.Energy & Industr