4,328 research outputs found
The Recognition of Fires Originating from Photovoltaic (PV) Solar Systems
No full textThere has been an observable increase in the fitting of photovoltaic (PV) solar panels on the roofs
of buildings in the UK over the last decade. The origin of some fires in domestic and commercial
properties has been attributed to PV systems. This thesis examines the ability of fire examiners to
recognise and record details of fires believed to have originated from PV systems, as well as
investigating the effect of internal heating in direct current (DC) isolators to the point at which they
fail.
National fire data was examined along with the methods for collecting and collating these data.
This clarified that national fire data cannot identify the specifics of electrical fires. Validity of these
data was then tested by identifying the confidence and competence in the recognition of the origin
of fire, (especially when associated with PV systems), of some fire staff responsible for collecting
fire data. This suggests that some fire scenes examiners are not confident in their own ability to
recognise fires originating from PV systems. Evidence for fires occurring in PV systems in Kent
between 2009 and 2014 was then examined, including a cold case forensic review of the
evidence. This provided an indication that a potential common point of failure, which may lead to
fire originating from a PV system, was to be found within the DC section of the PV circuits and
probably within the DC isolator switch itself. Experimentation revealed that internal heating of a
terminal connection can lead to changes of the phase of the insulating material, causing failure of
structural integrity and therefore allowing an arc to be established. Observable post fire indicators
associated with this mechanism of failure have been identified as well as hydrocarbons evolved
from pyrolysis of isolator insulating material.
Finally, areas for further experimental research and training of fire staff are suggested as well as
the modification of recording mechanisms and building regulations
Understanding innovation system build up: The rise and fall of the Dutch PV Innovation System
No full textRenewable energy technologies have a hard time to break through in the existing energy regime. In this paper we focus on analysing the mechanisms behind this problematic technology diffusion. We take the theoretical perspective of innovation system dynamics and apply this to photovoltaic solar energy technology (PV) in the Netherlands. The reason for this is that there is a long history of policy efforts in The Netherlands to stimulate PV but results in terms of diffusion of PV panels is disappointingly low, which clearly constitutes a case of slow diffusion. The history of the development of the PV innovation system is analysed in terms of seven key processes that are essential for the build up of innovation systems. We show that the processes related to knowledge development are very stable but that large fluctuations are present in the processes related to ‘guidance of the search’ and ‘market formation’. Surprisingly, entrepreneurial activities are not too much affected by fluctuating market formation activities. We relate this to market formation in neighbouring countries and discuss the theoretical implications for the technological innovation system framework.Photovoltaic, Innovation system dynamics, Motors of Change
Electrical impact of photovoltaic plant in distributed network
No full textThis paper presents the problem of the power penetration of photovoltaic (PV) systems in urban networks. After a qualitative problem description, two different environments for the PV systems have been analyzed: rural and urban networks. Concerning the rural network a single line has been simulated in order to evaluate the relation between the number of PV system installed along the line and the maximum PV power installable. In the second part of the paper the possible problems due to the power penetration have been examined concerning a clustered PV system that will be installed in the city of Torino (Italy) in ambit of an EU project
Electrical Impact Of Photovoltaic Plant In Distributed Network
No full textThis paper presents the problem of power penetration of photovoltaic (PV) systems in urban networks. After a qualitative problem description, two different environments for PV systems have been analyzed: rural and urban networks. Concerning the rural network, a single line has been simulated in order to evaluate the relation between the number of PV systems installed along the line and the maximum PV power installable. In the second part of this paper, possible problems due to power penetration have been examined concerning a clustered PV system that will be installed in the city of Torino (Italy) within the ambit of the EU project called POLYCIT
Electrical design for a 10kW photovoltaic trough concentrator system installed at the Murdoch University South Street Campus
No full textThe Electrical design of the 10kW Photovoltaic (PV) Trough Concentrator System involves the use of equipment from the original Rockingham Campus PV system to achieve the aim of exporting power to the South West Interconnected System (SWIS) electrical grid.The 10kW system has been designed to all relevant Australian Standards, in particular AS5033:2005 Installation of photovoltaic (PV) arrays and AS4777:2005 Grid connection of energy systems via inverters.Using the university’s Spire Solar Simulator, all 80 of the photovoltaic receivers have been tested for functionality and degradation, and from these test results the most suitable 40 receivers in terms of power output and mismatch effects were selected and installed.
The results have been documented and placed into the university’s engineering computer directory for future reference.The test results have enabled the electrical design and configuration for the PV array to be completed with the inverter and associated electrical equipment specified.Part B of this report involved two additional projects that were undertaken. The first being the overhaul of an unsafe PV array structure that required major repairs to enable the array to be moved, and the second, the design and implementation of two new structures including fabrication and construction of new beams, bearings and gearboxes, to enable future PV arrays to be constructed for future use by engineering students.These two tasks required project management skills to liaise, communicate and supervise with contractors that were sourced for the projects. The projects were completed safely and to a high standard.The 10 kW PV array, though not yet electrically connected, has shown under concentration tests that it can produce up to approximately 80% of its rated output power when the receivers are aligned correctly.In view of the above, the PV array when connected should perform close to design specifications and should be an invaluable tool for the learning requirements of future engineering students
Equatorwards-breaking Rossby waves in the North Atlantic storm track : forecast quality, predictability and dynamics
No full textUpper-level disturbances (ULDs) penetrating from the extratropics into low lati- tudes are a frequent feature of the synoptic-scale circulation over the North Atlantic and can be involved in significant weather events such as heavy precipitation over the western and northern parts of Africa, or Saharan dust outbreaks. The present project is the first to systematically explore the huge dynamical information content of long-term data from the European Centre for Medium-Range Weather Forecasts operational ensemble prediction system (EPS) and from the recently established THORPEX Interactive Grand Global Ensemble (TIGGE) for that particular at- mospheric feature. It investigates the dynamics, forecast quality and predictability of this atmospheric phenomenon exploring a wide range of verification and analysis tools based on potential vorticity (PV). The main conclusions from this work are: (i) The EPSs shows a generally underdispersive behaviour in the ULD region. (ii) Forecast errors are reduced by about 50% if each TIGGE centre's own analysis is used instead of the ECMWF analysis, particularly in regions of large PV gradients. (iii) There is a tendency of too weak Rossby wave breaking and therefore a north- ward shift of the PV streamers in the forecasts. (iv) Ensemble-mean multi-model forecasts of a four-day accumulated precipitation event appear accurate enough for a successful severe-weather warning in contrast to some single-model EPSs. (v) Diabatic processes upstream early in the forecasts appear to be more impor- tant than blocking downstream for strengthening the PV streamers in the medium range. The results and the analysis tools developed in this project have improved the understanding of such ULDs and their impacts and has advanced the verifica- tion of EPSs, which can both contribute to an improvement of numerical weather forecasting in the long term
Technology roadmap: solar photovoltaic energy - 2014 edition
No full textSolar power enhances energy diversity and hedges against price volatility of fossil fuels, thus stabilising costs of electricity generation in the long term, argues this report.
Overview
Solar energy is widely available throughout the world and can contribute to reduced dependence on energy imports. As it entails no fuel price risk or constraints, it also improves security of supply. Solar power enhances energy diversity and hedges against price volatility of fossil fuels, thus stabilising costs of electricity generation in the long term.
Solar PV entails no greenhouse gas (GHG) emissions during operation and does not emit other pollutants (such as oxides of sulphur and nitrogen); additionally, it consumes no or little water. As local air pollution and extensive use of fresh water for cooling of thermal power plants are becoming serious concerns in hot or dry regions, these benefits of solar PV become increasingly important.
Key findings:
Since 2010, the world has added more solar photovoltaic (PV) capacity than in the previous four decades. Total global capacity overtook 150 gigawatts (GW) in early 2014
The geographical pattern of deployment is rapidly changing. While a few European countries, led by Germany and Italy, initiated large-scale PV development, since 2013, the People’s Republic of China has led the global PV market, followed by Japan and the United States
PV system prices have been divided by three in six years in most markets, while module prices have been divided by five
This roadmap envisions PV’s share of global electricity reaching 16% by 2050, a significant increase from the 11% goal in the 2010 roadmap
Achieving this roadmap’s vision of 4 600 GW of installed PV capacity by 2050 would avoid the emission of up to 4 gigatonnes (Gt) of carbon dioxide (CO2) annually
This roadmap assumes that the costs of electricity from PV in different parts of the world will converge as markets develop, with an average cost reduction of 25% by 2020, 45% by 2030, and 65% by 2050, leading to a range of USD 40 to 160/MWh, assuming a cost of capital of 8%
To achieve the vision in this roadmap, the total PV capacity installed each year needs to rise from 36 GW in 2013 to 124 GW per year on average, with a peak of 200 GW per year between 2025 and 2040
The variability of the solar resource is a challenge. All flexibility options – including interconnections, demand-side response, flexible generation, and storage –need to be developed to meet this challenge
Appropriate regulatory frameworks – and well-designed electricity markets, in particular – will be critical to achieve the vision in this roadmap
Levelised cost of electricity from new-built PV systems and generation by sector
Multi-objective design optimisation of standalone hybrid wind-PV-diesel systems under uncertainties
No full textOptimal design of a standalone wind-PV-diesel hybrid system is a multi-objective optimisation problem with conflicting objectives of cost and reliability. Uncertainties in renewable resources, demand load and power modelling make deterministic methods of multi-objective optimisation fall short in optimal design of standalone hybrid renewable energy systems (HRES). Firstly, deterministic methods of analysis, even in the absence of uncertainties in cost modelling, do not predict the levelised cost of energy accurately. Secondly, since these methods ignore the random variations in parameters, they cannot be used to quantify the second objective, reliability of the system in supplying power. It is shown that for a given site and uncertainties profile, there exist an optimum margin of safety, applicable to the peak load, which can be used to size the diesel generator towards designing a cost-effective and reliable system. However, this optimum value is problem dependent and cannot be obtained deterministically. For two design scenarios, namely, finding the most reliable system subject to a constraint on the cost and finding the most cost-effective system subject to constraints on reliability measures, two algorithms are proposed to find the optimum margin of safety. The robustness of the proposed design methodology is shown through carrying out two design case studies
Thermal management of concentrator photovoltaics
No full textPhotovoltaic Concentrator systems, which increase the solar radiation intensity on the
photovoltaic cells, may reduce the system cost, if the cost of the concentrator is less than
the photovoltaic material displaced. An Asymmetric Compound Parabolic Photovoltaic
Concentrator (ACPPVC) for building façade integration with a solar concentration ratio of
2.0 has been designed, fabricated and experimentally characterised. The truncated
ACPPVC has acceptance half angles of 0° and 55° and an absorber width of 125mm. Phase
Change Materials (PCM) have been integrated to the rear of the PV panel to moderate the
temperature rise of the PV and maintain good solar-electrical conversion efficiency. The
thermal behaviour of a Fresnel lens PV Concentrator (FPVC) has also been studied in this
work.
A two-dimensional ray trace technique has been used to predict the optical performance
and the angular acceptance of the ACPPVC system. The predicted highest optical
efficiency was 88.67% for the ACPPVC-55 system. Extensive indoor experimental
characterisation of a number of PV systems was undertaken for a range of incident solar
radiation intensities using a highly collimated solar simulator developed specifically for this
project. Experimental results showed that the electrical output from the ACPPVC-55 was
approximately 1.8 of that of a non-concentrating PV system with similar solar cells area.
The electrical conversion efficiency for the ACPPVC-55 system was further increased,
when RT27 PCM was incorporated to its rear
Modelling and Simulation of a Grid-Connected PV System based on Efficient Maximum Power Point Tracking Algorithm
No full textThe results presented in this paper have been acquired through simulation of a grid-connected photovoltaic system (GCPV) to a specific section of Alsabyia generation station part of Kuwait national grid with efficient maximum power point tracking (MPPT) algorithm incorporated into a DC-DC boost converter. The simulations were performed using Power Simulation Software (PSIM). The analytical model of a photovoltaic (PV) module has been combined with a 'perturb and observe' (P&O) method so that MPP is achieved with the external temperature and solar radiation (SR) also considered. A DC-AC inverter is used to track the output voltage of the converter and interface the PV array with the grid. The results show that the model not only achieves the MPP function but also improves the output of the inverter by reducing the ripples in the sine waveforms
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