The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform

Kamf Jonas - One of the best experts on this subject based on the ideXlab platform.

  • Mooring forces in a floating point-absorbing WEC system – a comparison between full-scale measurements and numerical simulations
    'Informa UK Limited', 2020
    Co-Authors: Ringsberg Jonas, Yang Shun-han, Lang Xiao, Johnson Erland, Kamf Jonas
    Abstract:

    The study presents results from an investigation of Waves4Power’s WaveEL 3.0 wave energy converter (WEC), which was used as a reference for full-scale mooring line force measurements. The unique elastic mooring system of this WEC has three mooring legs, wherein each leg is divided into two mooring lines with an intermediate submerged floater. The mooring forces and buoy motions were continuously measured in a measurement campaign between June and November 2017 at an Installation Location off the coast of Runde in Norway.A numerical simulation model of the full-scale Installation was developed in the DNV GL software SESAM. The sea state conditions were not measured during the measurement campaign. A methodology was developed that used the recorded motion data to compute the sea state conditions (significant wave height, wave period, wave directionality) at the test site. The simulated WEC motions based on the computed sea states agreed very well with the measured WEC motions. The measured and simulated mooring forces were compared under various environmental conditions. Although 3-hour sea state realizations are typically preferred in numerical simulations, influences from the tide at the test site showed that sea states were normally stationary for only 1-2 hours. The measured and simulated average mooring forces agreed very well during 1-hour periods, whereas the simulations overestimated the mooring forces in 3-hour periods because of the tide. Finally, the results were discussed with regard to uncertainties in general and the prediction capacity of the numerical model

  • Mooring forces in a floating point-absorbing WEC system – a comparison between full-scale measurements and numerical simulations
    2019
    Co-Authors: Ringsberg Jonas, Yang Shun-han, Lang Xiao, Johnson Erland, Kamf Jonas
    Abstract:

    Functional elastic mooring system designs for floating point-absorbing wave energy converters (WECs) are important for WEC power capture and the durability and reliability of its mooring system. This study presents results from an investigation of Waves4Power’s WaveEL 3.0 WEC, which was used as a reference for full-scale mooring line force measurements. The unique elastic mooring system of this WEC has three mooring legs, wherein each leg is divided into two mooring lines with an intermediate submerged floater. The mooring forces and buoy motions were continuously measured in a measurement campaign between June and November 2017 at an Installation Location off the coast of Runde in Norway.A numerical simulation model of the full-scale Installation was developed in the DNV GL software SESAM. The sea state conditions were not measured during the measurement campaign. A methodology was developed that used the recorded motion data to compute the sea state conditions (significant wave height, wave period, wave directionality) at the test site. The simulated WEC motions based on the computed sea states agreed very well with the measured WEC motions. The measured and simulated mooring forces were compared under various environmental conditions. Although 3-hour sea state realizations are typically preferred in numerical simulations, influences from the tide at the test site showed that sea states were normally stationary for only 1-2 hours. The measured and simulated average mooring forces agreed very well during 1-hour periods, whereas the simulations overestimated the mooring forces in 3-hour periods because of the tide. Finally, the results were discussed with regard to uncertainties in general and the prediction capacity of the numerical model

Francis Osullivan - One of the best experts on this subject based on the ideXlab platform.

  • parametric modeling of life cycle greenhouse gas emissions from photovoltaic power
    Applied Energy, 2019
    Co-Authors: Ian Miller, Emre Gencer, Hilary S Vogelbaum, Patrick R Brown, Sarah Torkamani, Francis Osullivan
    Abstract:

    Abstract From 2007 to 2017, global installed solar photovoltaic power capacity grew by a factor of 50. Practices that were minor, including solar tracking, inverter overloading, and Chinese module manufacturing, became mainstream. Countries including the US and India installed large amounts of solar in warm regions with mean temperatures above 20 °C. The impacts of these developments on greenhouse gas emissions from photovoltaic power have not been analyzed by life cycle assessment in depth. This study helps to fill that gap. A modeling tool is built that integrates photovoltaic life cycle inventories, background emission factors, known physical correlations, and modern photovoltaic performance modeling, including temperature-dependent performance ratios. Using this tool, four novel findings are produced on life cycle greenhouse gas emissions from photovoltaic power, referred to here as carbon intensity. Firstly, reversible temperature effects on modules raise the carbon intensity of silicon photovoltaic power installed in warm regions, including by 10% in the southwestern US and 13% in western India. All temperature effects raise silicon photovoltaic carbon intensity by ∼23% in southern India (from 35 to 43 gCO2e/kWh). Secondly, emission impacts of tracking, relative to stationary mounting, depend on Installation Location and module type. For multi-crystalline silicon and cadmium telluride modules, respectively, adding tracking changes carbon intensity by −11% and −3% in the southwestern US, and by −4% and +5% in eastern Australia. This dependence on Location and module type, and the novel result that tracking can increase emissions intensity, is explained by interactions between tracking energy gain, tracker production emissions, and module production emissions. Thirdly, Chinese manufacturing of multi-crystalline silicon modules emits ∼25% more greenhouse gases than European manufacturing, due not only to higher carbon intensity of upstream electricity, as previously reported, but also to more electricity and fuel input per module produced. Fourthly, inverter overloading as practiced slightly diminishes photovoltaic carbon intensity, by less than 2 gCO2e/kWh. Finally, mainstream photovoltaic power in all its forms has significantly lower life cycle greenhouse gas emissions than fossil power.

Eric Hu - One of the best experts on this subject based on the ideXlab platform.

  • life cycle assessment and evaluation of energy payback time on high concentration photovoltaic power generation system
    Applied Energy, 2010
    Co-Authors: Akira Nishimura, S. Kato, Masafumi Hirota, Kenji Araki, Y. Hayashi, K. Tanaka, Eric Hu
    Abstract:

    In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of Installation Location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100Â MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64Â year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27Â year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188Â kWÂ h/(m2Â year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.

Andrea L Hicks - One of the best experts on this subject based on the ideXlab platform.

  • effect of manufacturing and Installation Location on environmental impact payback time of solar power
    Clean Technologies and Environmental Policy, 2020
    Co-Authors: Courtney Grant, Andrea L Hicks
    Abstract:

    Solar photovoltaic (PV) systems are a promising technology to reduce the environmental impacts of electricity production. Several Locations in the USA are favorable for solar PV deployment due to having a high solar potential. This study evaluates the environmental impact payback time (PBTI) for installing multi-crystalline silicon PV systems in multiple US cities, Seattle, Miami, Los Angeles, Phoenix and Indianapolis, with varying electricity mixes and solar potential, using life cycle inventory data and the Tool for the Reduction and Assessment of Chemicals and other environmental impacts as the impact assessment method. China, USA and European manufacturing scenarios were analyzed to compare the effect of the electricity mix used during manufacturing on PBTI. The results show that the PBTI ranges between < 1 year and 3000 + years across all impact categories. A Chinese manufacturing scenario increased the PBTI in some impact categories (i.e., global warming) compared to the USA and Europe manufacturing, but had no effect for others. The PBTI is within the solar panel life span for the impact categories of global warming, acidification and fossil fuel depletion, but is longer than the lifespan for other impact categories (i.e., eutrophication and ozone depletion). According to the global warming PBTI, policies should incentivize solar panels in the following order: Phoenix, Indianapolis, Miami, Los Angeles, Seattle. This work provides guidance to policy makers and manufacturers on the PBTI when the manufacturing Location, solar potential and electricity mix are known.

Mohamad Fani Sulaima - One of the best experts on this subject based on the ideXlab platform.

  • impact of solar photovoltaic system on transformer tap changer in low voltage distribution networks
    Energy Procedia, 2016
    Co-Authors: Zainal Salam, Mohamad Fani Sulaima
    Abstract:

    Abstract This paper investigates the impact of solar resource variability on the operation of a low-voltage On-Load-Tap-Changer (OLTC) in a generic distribution network from the Malaysian grid. The OLTC's operation is studiedin two different weather conditions—sunny and cloudy days. The aspects analysed are the OLTC's time delay setting, PV penetration levels and PV Installation Location. The results suggest that the number of tap changes in a cloudy day is approximately 1.5 times higher than in a sunny day. In addition, at 50% PV penetration level on a cloudy day, the OLTC operation increases by 38% and it is doubled at 100% penetration.