• Energy Research

A longstanding question in the study of energy demand concerns the role of information as a determinant of home efficiency improvements. Although the provision of information via energy audits is frequently asserted to be an effective means for governments to encourage the implementation of efficiency-enhancing renovations, empirical support for this assertion is tenuous at best. Apart from endogeneity issues with respect to receiving an audit, two other factors have complicated attempts to measure their effect: First, the nature of the information provided by the audit is typically unobserved, and, second, the response to this information may vary over households. Using household data from Germany, we address both sources of heterogeneity by estimating a random-parameter model of four retrofitting alternatives. In addition to confirming the importance of costs and savings as determinants of renovation choices, our results suggest that the effects of consultancy vary substantially across households, with some households responding negatively to the provision of information.

Abstract This study extends an energy-balance-equation wave model (a phase-averaging wave model) for multidirectional random wave transformations to account for wave shoaling, refraction, diffraction, reflection and breaking. Quadratic upstream interpolation for convective kinematics is used in the discretization to reduce numerical diffusion. Predictions using the present wave model are compared with Sommerfeld's solutions for wave transformation through a gap between breakwaters, experimental observations for wave transformation due to a circular shoal, and field measurements for waves behind a breakwater. The results of these comparisons show fairly good agreement.

Among the latest achievements in gasification technology, one may list the development of a method to preheat gasification agents using switched ceramic honey combs. The best output from this technology is achieved with use of water steam as a gasification agent, which is heated up to 1600 °C. The application of these temperatures with steam as a gasification agent provides a cleaner syngas (no nitrogen from air, cracked tars) and the ash melts into easily utilised glass-like sludge. High hydrogen content in output gas is also favourable for end-user applications.Among the other advantages of this technology is the presumable application of fixed-bed-type reactors fed by separately produced and preheated steam. This construction assumes relatively high steam flow rates to deliver the heat needed for endothermic reactions involving biomass. The biomass is to be heated uniformly and evenly in the volume of the whole reactor, providing easier and simpler control and operation in comparison to other types of reactors. To provide potential constructors and exploiters of these reactors with the kinetic data needed for the calculations of vital parameters for both reactor construction and exploitation, basic experimental research of high-temperature steam gasification of four types of industrially produced biomass has been conducted.Kinetic data have been obtained for straw and wood pellets, wood-chip charcoal and compressed charcoal of mixed origin. Experiments were conducted using two experimental facilities at the Energy and Furnace Division of the Department of Material Science and Engineering (MSE) at the School of Industrial Engineering and Management (ITM) of the Royal Institute of Technology (KTH) and at the Combustion Laboratory of the Mechanical Engineering Department of the University of Maryland (UMD), USA. The experimental facility at the Energy and Furnace Division has been improved with the addition of several constructive elements, providing better possibilities for thermo-gravimetric measurements.The obtained thermo-gravimetric data were analysed and approximated using several models described in the literature. In addition, appropriate software based on the Scilab package was developed. The implementation of the isothermal method based on optimisation algorithms has been developed and tested on the data obtained under the conditions of a slow decrease of temperature in experiments with the char gasification in small-scale experimental facilities in the Energy and Furnace Division.The composition of the gases generated during the gasification of straw and wood pellets by high-temperature steam has been recorded and analysed for different experimental conditions. QC 20101124 Study of ignition and kinetics of biomass/solid waste thermal conversion with high-temperature air/steam

This study aims to test the relevance of EKC hypothesiswhile also test the impact of percapita GDP and energy consumption percapita towards environmental degradationin lower-middle, upper-middle, and high income countries over the period of 1985 - 2014. This study uses panel data method and Random Effect Model (REM) approach for lower-middle and high income countries, while for upple-middle income country uses Fixed Effect Model (FEM) approach. This study findsthat the EKC hypothesis is relevant in upper-middle income country, with the turning point of percapita GDP at USD 9,143. In addition, this study also findsthat energy consumption percapitahasa positive and significant impact on environmental degradation in all income groups, and percapita GDP hasa positive and significant impact on environmental degradation in lower-middle and upper-middle country, meanwhile a negative and significant impact in high income country.

A longstanding question in the study of energy demand concerns the role of information as a determinant of home-efficiency improvements. Although the provision of information via home energy audits is frequently asserted to be an effective means for governments to encourage the implementation of efficiency-enhancing renovations,empirical support for this assertion is tenuous at best. Two factors have complicated attempts to measure the effect of audits: first, the nature of the information provided by the audit is typically unobserved, and, second, the response to this information may vary over households. Using household-level data from Germany, we address both sources of heterogeneity by estimating a random-parametermodel of four retrofitting alternatives. In addition to confirming the importance of costs and savings as determinants of renovation choices, our results suggest that the effects of consultancy vary substantially across households, with some households responding negatively to the provision of information. Discussion Paper / SFB 823;41/2011

We investigate the long-time behavior of the Glauber dynamics for the random energy model below the critical temperature. We give very precise estimates on the motion of the process to and between the states of extremal energies. We show that when disregarding time, the consecutive steps of the process on these states are governed by a Markov chain that jumps uniformly on all possible states. The mean times of these jumps are also computed very precisely and are seen to be asymptotically independent of the terminal point. A first indicator of aging is the observation that the mean time of arrival in the set of states that have waiting times of order T is itself of order T . The estimates proven in this paper will furnish crucial input for a follow-up paper where aging is analysed in full detail.

We consider the parabolic Anderson model (PAM) on the n-dimensional hypercube with random i.i.d. potentials. We parametrize time by volume and study the solution at the location of the k-th largest potential. Our main result is that, for a certain class of potential distributions, the solution exhibits a phase transition: for short time scales it behaves like a system without diffusion, whereas, for long time scales the growth is dictated by the principle eigenvalue and the corresponding eigenfunction of the Anderson operator, for which we give precise asymptotics. Moreover, the transition time depends only on the difference between the largest and k-th largest potential. One of our main motivations in this article is to investigate the mutation-selection model of population genetics on a random fitness landscape, which is given by the ratio of the solution of PAM to its total mass, with the field corresponding to the fitness landscape. We show that the phase transition of the solution translates to the mutation-selection model as follows: a population initially concentrated at the site of the k-th best fitness value moves completely to the site of the best fitness on time scales where the transition of growth rates happens. The class of potentials we consider involve the Random Energy Model (REM) of statistical physics which is studied as one of the main examples of a random fitness landscape.

Reducing the usage of fossil fuels is a central issue in ongoing policy debates. This in particular holds for Dutch horticulture, given its energy-intensive production. We analyse differences in energy usage and price responsiveness of horticultural firms by estimating energy demand functions using a Bayesian random coefficient model. Beyond, the effects of a proposed energy tax are assessed. Allowing for firm-specific energy price coefficients gives a better model fit compared to conventional models with fixed slope parameters. This confirms that firms respond differently to energy prices, which is taken into account in simulating the effects of more restrictive energy policies. The results show that larger-sized firms use less gas per square meter yet also point at a considerable spread in additional energy expenses between firms.