Per Bromand Nørgård

Superconducting wind turbine generators

We have examined the potential of 10?MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10?MW have been determined from an up-scaling of an existing 5?MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10?kW, 100?kW, 1?MW and 10?MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10?kW and an extreme high field 10?MW generator are found to be 7.5?km and 1500?km, respectively. A more realistic estimate is 200?300?km of tape per 10?MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

Design Study of 10 kW Superconducting Generator for Wind Turbine Applications

We have performed a design study of a 10 kW superconducting slow rotating generator suitable for demonstration in a small scale wind turbine, where the drive train only consists of the turbine blades connected directly to the generator. The flux density in the superconducting rotor is chosen as B = 1 Tesla to be similar to the performance of permanent magnets and to represent a layout, which can be scaled up in future off-shore wind turbines. The proposed generator is a 8 pole synchronous machine based on race-track coils of high temperature superconducting tapes and an air cored copper stator enclosed in an iron shield.

Wind and Photovoltaic Large-Scale Regional Models for Hourly Production Evaluation

This work presents two large-scale regional models used for the evaluation of normalized power output from wind turbines and photovoltaic power plants on a European regional scale. The models give an estimate of renewable production on a regional scale with 1h resolution, starting from a mesoscale meteorological data input and taking in account the characteristics of different plants technologies and spatial distribution. An evaluation of the hourly forecasted energy production on a regional scale would be very valuable for the transmission system operators when making the long-term planning of the transmission system, especially regarding the cross-border power flows. The tuning of these regional models is done using historical meteorological data acquired on a per-country basis and using publicly available data of installed capacity.

Electrical Vehicle Batteries Testing in a Distribution Network Using Sustainable Energy

EV technologies are still relatively new and under strong development. Many different designs and choices of technologies have been pursued by the automotive OEMs, battery industry and EV research centers. Although some standardized solutions are being promoted and becoming a new trend, there is an outstanding need for common platforms and sharing of knowledge and core technologies. This paper presents the development of a test platform, including three Li-ion batteries designed for EV applications and three associated bi-directional power converters, for testing impacts on different advanced loadings of EV batteries. The aim of the tests has been to study the impact of smart charging and fast charging on the power system, on the battery state of health and degradation, and to find out the limitations of the batteries for a Smart Grid. The paper outlines the advantages and disadvantages of both tests in terms of regulation of the aggregated local power, power capacity and the power exchange with the grid.

Domestic refrigerators temperature prediction strategy for the evaluation of the expected power consumption

This paper discusses and presents a simple temperature prediction strategy for the domestic refrigerator. The main idea is to predict the duration it takes to the cold chamber temperature to reach the thresholds according to the state of the compressor and to the last temperature measurements. The experiments are conducted at SYSLAB facility at DTU Risø Campus having a set of refrigerators working at different set point temperatures, with different ambient temperatures and under different thermal load conditions. The prediction strategy is tested using a set of different refrigerators in order to validate the performances. The challenges to calculate the time with less error pronouncement in temperature, regulating power supply and its duration are also discussed.

Energy shift estimation of demand response activation on refrigerators — A field test study

This paper presents a method to estimate the amount of energy that can be shifted during demand response (DR) activation on domestic refrigerator. Though there are many methods for DR activation like load reduction, load shifting and onsite generation, the method under study is load shifting. Electric heating and cooling equipment like refrigerators, water heaters and space heaters and coolers are preferred for such DR activation because of their energy storing capacity. Accurate estimation of available regulating power and energy shift is important to understand the value of DR activation at any time. In this paper a novel method to estimate the available energy shift from domestic refrigerators with only two measurements, namely fridge cool chamber temperature and compressor power consumption is proposed, discussed and evaluated.

Charging and discharging tests for obtaining an accurate dynamic electro-thermal model of high power lithium-ion pack system for hybrid and EV applications

This paper presents a battery test platform including two Li-ion battery designed for hybrid and EV applications, and charging/discharging tests under different operating conditions carried out for developing an accurate dynamic electro-thermal model of a high power Li-ion battery pack system. The aim of the tests has been to study the impact of the battery degradation and to find out the dynamic characteristics of the cells including nonlinear open circuit voltage, series resistance and parallel transient circuit at different charge/discharge currents and cell temperature. An equivalent circuit model, based on the runtime battery model and the Thevenin circuit model, with parameters obtained from the tests and depending on SOC, current and temperature has been implemented in MATLAB/Simulink and Power Factory. A good alignment between simulations and measurements has been found.

Economic Dispatch of Hydrogen Systems in Energy Spot Markets

Economic Dispatch of Hydrogen Systems in Energy Spot Markets Hydrogen system, as a new energy carrier, could deliver clean and efficient energy services in a wide range of applications. This paper presents an economic dispatch-based mathematical model that facilitates investigations on the techno-economic feasibility of hydrogen systems in the context of energy spot markets. The generic hydrogen system is comprised of an electrolysis for hydrogen production, a hydrogen storage tank and a fuel cell system for cogeneration of electricity and heat. A case study is presented with information from practical hydrogen systems and the Nordic energy markets to demonstrate the effectiveness of the proposed model and approach.

Superconducting wind turbines

In this project we shall investigate the feasibility of using type II high temperature superconductors in electric generators of future off shore wind turbines. High temperature superconductors can be used to generate a considerable higher magnetic field than in classical magnet designs and thereby reduce weight. The purpose is to assess the technical and economical feasibility of using superconducting generators for sea based wind turbines producing 10-20 MW.