Energy performance of concentrator and flat plate photovoltaics in the mediterranean area
A comparative analysis of the energy production of a High Concentrator Photovoltaic (CPV) and a flat plate amorphous photovoltaic (PV) plants, installed in the same place in the southern Italy, is presented. This analysis aims at providing reliable production values of CPV based on a long term monitoring with reference to this specific geographic zone. The daily normalized power production in different weather conditions is presented and the correlation between energy production and daily solar irradiance is discussed. Further, a statistical analysis on the normalized energy production is developed for both plants, referring to the measured historical data. Finally, economic aspects and the evaluation of levelized cost of energy for CPV based on in-field data are reported. On the basis of these considerations, the feasibility of CPV systems in southern Europe are discussed.
Levelized Cost of Electricity: PV and CPV in Comparison to Other Technologies
This paper presents the findings of the Fraunhofer ISE study on the levelized cost of electricity (LCOE) of renewable energy technologies with a focus on PV (Fraunhofer ISE, 2013). It predicts future cost and market developments through 2030 based on technology-specific learning curves and market scenarios. Photovoltaics (PV) are assessed in Germany. Moreover, the solar technologies PV and concentrating photovoltaics (CPV) are analyzed in regions with higher solar irradiation. They are compared to other renewable energy technologies such as (onshore and offshore) wind power, concentrating solar power (CSP) and biogas on the basis of common market financing costs. The current and future LCOE for new conventional power plants (brown coal, hard coal, combined cycle gas turbine (CCGT), oil-fired power plants) are calculated as a reference.
Neutron Residual Stress Measurements on Rail Sections for Different Production Conditions
Rail sectioning with subsequent neutron diffraction experiments has been used to assess residual stresses in the rails. In this study we present the results of neutron stress measurements performed at the NIST Center for Neutron Research (NCNR) on rail sections from rails that were produced under various conditions. Specifically, these are air-cooled, air-cooled and roller-straightened, head-hardened and head-hardened and roller-straightened. More significantly, a head-hardened and roller-straightened rail was also studied after service to elucidate evolution of the service-induced residual stresses. In the latter case both a transverse-cut slice and the central region of a 0.53 m long piece were studied. Measurements on this piece are the first in which triaxial stresses have been determined for an intact rail. Neutron strain measurements with 3×3×3 mm3 spatial resolution were successfully employed for transversally cut slices to verify the difference in the stress state depending on the production process. Although examination of slices allows determination of only two-dimensional stresses in the plane of the slice, additional measurements on obliquely-cut slices, which were also carried out, and utilization of FEM gives the possibility of reconstructing the full triaxial stress distribution. Together, these approaches provide a better understanding of rail fabrication and the possibility of improving the durability and safety of rails in the future.Copyright © 2004 by ASME