• Energy Research

Abstract An assessment is made of on-the-road performance, for a pure hydrogen fuel cell car, a pure battery operated car, and a hydrogen fuel cell-battery hybrid car. The tool used for this study is the modular software-package ADVISOR [Markel T, et al. ADVISOR. J Power Sources 2002; 110:255–66], which is well tested and offers a range of simple, parametrized sub-models or more detailed physical models for the fuel cell stack, the batteries, the electric motor, the exhaust control, the transmission and entire power train including controls and control strategies. The basis configurations of the cars modelled is characterized by high energy efficiency, before adding a fuel cell and electric motor also of high conversion efficiencies. Preceding the presentation of results, the best way to characterize energy efficiency is discussed.

A simple optimization of a crystalline silicon solar cell is performed using a one-dimensional finite element calculation, and a neural network is subsequently trained to reproduce the data. The quality of this reproduction is discussed. Considering that translation of the original problem to run on a trained neural network permits a reduction of calculation time by three to six orders of magnitude, the scope for continued work on and extension of this method appears appealing.

Abstract Global climate warming mitigation efforts are more likely to be successful if they are based on per-capita emissions rather than on complex negotiated emission rights. I propose a path to temperature stabilisation optimised for each country and reaching a common per-capita rate of greenhouse gas emissions by the end of the 21st century. Consistent emission pathways for given levels of temperature stabilisation are calculated by use of a simple model that is consistent with the circulation models and data sets surveyed by the Intergovernmental Panel on Climate Change. The allowable emissions are detailed on a regional level and on individual country level. I discuss the merits of this type of approach relative to other policy approaches, as well as some of the objections that may be voiced.

Abstract An imlementation of life-cycle analysis (LCA) for energy systems is presented and applied to two renewable energy systems (wind turbines and building-integrated photovoltaic modules) and compared with coal plants.

ENERGY STORAGE OPTIONS CAN BE SEGMENTED BY THE LENGTH OF STORAGE THAT THEY OFFER. LONG-TERM STORAGE SUCH AS HYDRO RESERVOIRS MAY STORE ENERGY FOR MANY MONTHS AND HAVE AN IMPORTANT IMPACT ON THE OVERALL ENERGY BUDGET, WHILE SMALL-TIME STORAGE SUCH AS CAPACITORS CAN HELP AVOID FLICKERING OF THE LIGHT WHEN NET COMPANIES SWITCH BETWEEN DIFFERENT ELECTRICITY SUPPLIERS. IN THIS ARTICLE BENT SORENSEN ASSESSES A SELECTION OF SHORT-TERM ENERGY STORAGE DEVICES AND THEIR FIELDS OF APPLICATION.

THE INTERMITTENCY OF RENEWABLES IS FORCING ENERGY PROVIDERS TO LOOK AT WAYS TO STORE ENERGY – AS A WAY TO GUARANTEE STABLE SUPPLY. IN A NEW REGULAR COLUMN LOOKING AT THE ENERGY STORAGE CONUNDRUM, BENT SORENSEN FROM ROSKILDE UNIVERSITY IN DENMARK LOOKS AT A CLASSIC CASE OF ENERGY STORAGE – VEHICLES THAT USE BATTERIES AND FUEL CELLS.

An approach to energy systems modelling is presented. It employs a mixture of non–linear programming techniques considered suitable for the particular structure of energy models, in order to overcome the problems encountered in optimisation with a non–trivial objective function topology, e.g. with several local minima. Preliminary results for a European energy model are presented.