Reliability based design of fluid power pitch systems for wind turbines

This paper presents a qualitative design tool for evaluation of the risk for fluid power pitch systems. The design tool is developed with special attention to industry standard failure analysis methods and is aimed at the early phase of system design. Firstly, the concept of Fault Tree Analysis is used for systematic description of fault propagation linking failure modes to system effects. The methodology is conducted solely on a circuit diagram and functional behavior. The Failure Mode and Effects Criticality Analysis is subsequently employed to determine the failure mode risk via the Risk Priority Number. The Failure Mode and Effect Criticality Analysis is based on past research concerning failure analysis of wind turbine drive trains. Guidelines are given to select the severity, occurrence and detection score that make up the risk priority number. The usability of the method is shown in a case study of a fluid power pitch system applied to wind turbines. The results show a good agreement to recent field failure data for offshore turbines where the dominating failure modes are related to valves, accumulators and leakage. The results are further used for making design improvements to lower the overall risk of the pitch system

Electricity portfolio innovation for energy security: the case of carbon constrained China

China’s energy sector is under pressure to achieve secure and affordable supply and a clear decarbonisation path. We examine the longitudinal trajectory of the Chinese electricity supply security and model the near future supply security based on the 12th 5 year plan. Our deterministic approach combines Shannon-Wiener, Herfindahl-Hirschman and electricity import dependence indices for supply security appraisal. We find that electricity portfolio innovation allows China to provide secure energy supply despite increasing import dependence. It is argued that long-term aggressive deployment of renewable energy will unblock China’s coal-biased technological lock-in and increase supply security in all fronts. However, reduced supply diversity in China during the 1990s will not recover until after 2020s due to the long-term coal lock-in that can threaten to hold China’s back from realising its full potential

Considerations in relation to off-site emergency procedures and response for nuclear accidents

The operation of nuclear facilities has, fortunately, not led to many accidents with off-site consequences. However, it is well-recognised that should a large release of radioactivity occur, the effects in the surrounding area and population will be significant. These effects can be mitigated by developing emergency preparedness and response plans prior to the operation of the nuclear facility that can be exercised regularly and implemented if an accident occurs. This review paper details the various stages of a nuclear accident and the corresponding aspects of an emergency preparedness plan that are relevant to these stages, both from a UK and international perspective. The paper also details how certain aspects of emergency preparedness have been affected by the accident at Fukushima Dai-ichi and as a point of comparison how emergency management plans were implemented following the accidents at Three Mile Island 2 and Chernobyl. In addition, the UK’s economic costing model for nuclear accidents COCO-2, and the UK’s Level-3 Probabilistic Safety Assessment code “PACE” are introduced. Finally, the factors that affect the economic impact of a nuclear accident, especially from a UK standpoint, are described

Assessing the potential of utilisation and storage strategies for post-combustion CO2 emissions reduction

The emissions reduction potential of three carbon dioxide handling strategies for post-combustion capture is considered. These are carbon capture and sequestration/storage (CCS), enhanced hydrocarbon recovery (EHR), and carbon dioxide utilization (CDU) to produce synthetic oil. This is performed using common and comparable boundary conditions including net CO2 sequestered based on equivalent boundary conditions. This is achieved using a “cradle to grave approach” where the final destination and fate of any product is considered. The input boundary is pure CO2 that has been produced using a post-combustion capture process as this is common between all processes. The output boundary is the emissions resulting from any product produced with the assumption that the majority of the oil will go to combustion processes. We also consider the “cradle to gate” approach where the ultimate fate of the oil is not considered as this is a boundary condition often applied to EHR processes. Results show that while CCS can make an impact on CO2 emissions, CDU will have a comparable effect whilst generating income while EHR will ultimately increase net emissions. The global capacity for CDU is also compared against CCS using data based on current and planned CCS projects. Analysis shows that current CDU represent a greater volume of capture than CCS processes and that this gap is likely to remain well beyond 2020 which is the limit of the CCS projects in the database

A simple energy usage toolkit from manufacturing simulation data

A fundamental problem in energy management is the inability to clearly predict any possible energy saving opportunities. The cost of both under or overestimating potential returns on investment can be prohibitive to a decision maker. In recent years the simulation of energy usage using existing manufacturing simulation tools has increased in popularity among researchers, but it is energy managers who need to see the benefits of this discipline. This paper proposes an interactive manufacturing energy management tool which makes use of existing productivity simulation models for the prediction of energy usage. An interactive Microsoft® Excel® based tool is developed to control Lanner’s WITNESS® discrete-event simulation software using Microsoft® Visual Basic® for Applications. The tool has the ability to predict potential areas where energy saving opportunities can be made within a complex manufacturing line, and is accessible from management presentations and proposals. The interactivity of the tool provides an environment which facilitates efficient hypothesis testing. The paper includes an industrial case study where the approach was used to quantify theoretical savings from certain energy usage reduction scenarios within a complex automotive engine manufacturing line

Gas generation and wind power: A review of unlikely allies in the United Kingdom and Ireland

No single solution currently exists to achieve the utopian desire of zero fossil fuel electricity generation. Until such time, it is evident that the energy mix will contain a large variation in stochastic and intermittent sources of renewable energy such as wind power. The increasing prominence of wind power in pursuit of legally binding European energy targets enables policy makers and conventional generating companies to plan for the unique challenges such a natural resource presents. This drive for wind has been highly beneficial in terms of security of energy supply and reducing greenhouse gas emissions. However, it has created an unusual ally in natural gas. This paper outlines the suitability and challenges faced by gas generating units in their utilisation as key assets for renewable energy integration and the transition to a low carbon future. The Single Electricity Market of the Republic of Ireland and Northern Ireland and the British Electricity Transmission Trading Agreement Market are the backdrop to this analysis. Both of these energy markets have a reliance on gas generation matching the proliferation of wind power. The unlikely and mostly ignored relationship between natural gas generation and wind power due to policy decisions and market forces is the necessity of gas to act as a bridging fuel. This review finds gas generation to be crucially important to the continued growth of renewable energy. Additionally, it is suggested that power market design should adequately reward the flexibility required to securely operate a power system with high penetrations of renewable energy, which in most cases is provided by gas generation

Fundamental spray and combustion measurements of soy methyl-ester biodiesel

Although biodiesel has begun to penetrate the fuel market, its effect on injection processes, combustion and emission formation under diesel engine conditions remains somewhat unclear. Typical exhaust measurements from engines running biodiesel indicate that particulate matter, carbon monoxide and unburnt hydrocarbons are decreased, whereas nitrogen oxide emissions tend to be increased. However, these observations are the result of complex interactions between physical and chemical processes occurring in the combustion chamber, for which understanding is still needed. To characterize and decouple the physical and chemical influences of biodiesel on spray mixing, ignition, combustion and soot formation, a soy methyl-ester (SME) biodiesel is injected into a constant-volume combustion facility under diesel-like operating conditions. A range of optical diagnostics is performed, comparing biodiesel to a conventional #2 diesel at the same injection and ambient conditions. Schlieren high-speed imaging shows virtually the same vapour-phase penetration for the two fuels, while simultaneous Mie-scatter imaging shows that the maximum liquid-phase penetration of biodiesel is higher than diesel. Differences in the liquid-phase penetration are expected because of the different boiling-point temperatures of the two fuels. However, the different liquid-phase penetration does not affect overall mixing rate and downstream vapour-phase penetration because each fuel spray has similar momentum and spreading angle. For the biodiesel and diesel samples used in this study, the ignition delay and lift-off length are only slightly less for biodiesel compared to diesel, consistent with the fuel cetane number (51 for biodiesel, 46 for diesel). Because of the similarity in lift-off length, the differences in equivalence ratio distribution at the lift-off length are mainly affected by the oxygen content of the fuels. For biodiesel, the equivalence ratio is reduced, which, along with the fuel molecular structure and oxygen content, significantly affects soot formation downstream. Spatially resolved soot volume fraction measurements obtained by combining line-of-sight laser extinction measurements with planar laser-induced incandescence imaging show that the soot concentration can be reduced by an order of magnitude for biodiesel. These integrated measurements of spray mixing, combustion and quantitative soot concentration provide new validation data for the development of computational fluid dynamics spray, combustion and soot formation models suitable for the latest biofuels.This work was supported by the Spanish Ministry of Science and Innovation for Jean-Guillaume Nerva's visiting research, through the OPTICOMB project [TRA2007-67961-C03-01].Nerva, J.; Genzale, CL.; Kook, S.; García Oliver, JM.; Pickett, LM. (2013). Fundamental spray and combustion measurements of soy methyl-ester biodiesel. International Journal of Engine Research. 14(4):373-390. https://doi.org/10.1177/1468087412456688S373390144(2009). World Energy Outlook 2009. World Energy Outlook. doi:10.1787/weo-2009-enMonyem, A., & H. Van Gerpen, J. (2001). The effect of biodiesel oxidation on engine performance and emissions. Biomass and Bioenergy, 20(4), 317-325. doi:10.1016/s0961-9534(00)00095-7LAPUERTA, M., ARMAS, O., & RODRIGUEZFERNANDEZ, J. (2008). Effect of biodiesel fuels on diesel engine emissions. Progress in Energy and Combustion Science, 34(2), 198-223. doi:10.1016/j.pecs.2007.07.001Fisher, B. T., Knothe, G., & Mueller, C. J. (2010). Liquid-Phase Penetration under Unsteady In-Cylinder Conditions: Soy- and Cuphea-Derived Biodiesel Fuels Versus Conventional Diesel. Energy & Fuels, 24(9), 5163-5180. doi:10.1021/ef100594pFang, T., Lin, Y.-C., Foong, T. M., & Lee, C. (2009). Biodiesel combustion in an optical HSDI diesel engine under low load premixed combustion conditions. Fuel, 88(11), 2154-2162. doi:10.1016/j.fuel.2009.02.033Pastor, J. V., García-Oliver, J. M., Nerva, J.-G., & Giménez, B. (2011). Fuel effect on the liquid-phase penetration of an evaporating spray under transient diesel-like conditions. Fuel, 90(11), 3369-3381. doi:10.1016/j.fuel.2011.05.006Fisher, B. T., & Mueller, C. J. (2010). Liquid penetration length of heptamethylnonane and trimethylpentane under unsteady in-cylinder conditions. Fuel, 89(10), 2673-2696. doi:10.1016/j.fuel.2010.04.024Kim, H. J., Park, S. H., Suh, H. K., & Lee, C. S. (2009). Atomization and Evaporation Characteristics of Biodiesel and Dimethyl Ether Compared to Diesel Fuel in a High-Pressure Injection System. Energy & Fuels, 23(3), 1734-1742. doi:10.1021/ef800811gSuh, H. K., Roh, H. G., & Lee, C. S. (2008). Spray and Combustion Characteristics of Biodiesel∕Diesel Blended Fuel in a Direct Injection Common-Rail Diesel Engine. Journal of Engineering for Gas Turbines and Power, 130(3). doi:10.1115/1.2835354Pickett, L. M., & Siebers, D. L. (2006). Soot Formation in Diesel Fuel Jets Near the Lift-Off Length. International Journal of Engine Research, 7(2), 103-130. doi:10.1243/146808705x57793Pickett, L. M., Kook, S., Persson, H., & Andersson, Ö. (2009). Diesel fuel jet lift-off stabilization in the presence of laser-induced plasma ignition. Proceedings of the Combustion Institute, 32(2), 2793-2800. doi:10.1016/j.proci.2008.06.082Yoo, C. S., Richardson, E. S., Sankaran, R., & Chen, J. H. (2011). A DNS study on the stabilization mechanism of a turbulent lifted ethylene jet flame in highly-heated coflow. Proceedings of the Combustion Institute, 33(1), 1619-1627. doi:10.1016/j.proci.2010.06.147Pastor, J. V., Payri, R., Gimeno, J., & Nerva, J. G. (2009). Experimental Study on RME Blends: Liquid-Phase Fuel Penetration, Chemiluminescence, and Soot Luminosity in Diesel-Like Conditions. Energy & Fuels, 23(12), 5899-5915. doi:10.1021/ef9007328Benajes, J., Molina, S., Novella, R., & Amorim, R. (2010). Study on Low Temperature Combustion for Light-Duty Diesel Engines. Energy & Fuels, 24(1), 355-364. doi:10.1021/ef900832cPickett, L. M., & Siebers, D. L. (2002). An investigation of diesel soot formation processes using micro-orifices. Proceedings of the Combustion Institute, 29(1), 655-662. doi:10.1016/s1540-7489(02)80084-0Siebers, D. L., & Pickett, L. M. (2004). Injection Pressure and Orifice Diameter Effects on Soot in DI Diesel Fuel Jets. Thermo- and Fluid Dynamic Processes in Diesel Engines 2, 109-132. doi:10.1007/978-3-662-10502-3_7Pickett, L. M., & Siebers, D. L. (2004). Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure. Combustion and Flame, 138(1-2), 114-135. doi:10.1016/j.combustflame.2004.04.006Cheng, A. S., Upatnieks, A., & Mueller, C. J. (2006). Investigation of the impact of biodiesel fuelling on NOx emissions using an optical direct injection diesel engine. International Journal of Engine Research, 7(4), 297-318. doi:10.1243/14680874jer05005Cheng, A. S. (Ed), Upatnieks, A., & Mueller, C. J. (2007). Investigation of Fuel Effects on Dilute, Mixing-Controlled Combustion in an Optical Direct-Injection Diesel Engine. Energy & Fuels, 21(4), 1989-2002. doi:10.1021/ef0606456Klein-Douwel, R. J. H., Donkerbroek, A. J., van Vliet, A. P., Boot, M. D., Somers, L. M. T., Baert, R. S. G., … ter Meulen, J. J. (2009). Soot and chemiluminescence in diesel combustion of bio-derived, oxygenated and reference fuels. Proceedings of the Combustion Institute, 32(2), 2817-2825. doi:10.1016/j.proci.2008.06.140Fang, T., & Lee, C. F. (2009). Bio-diesel effects on combustion processes in an HSDI diesel engine using advanced injection strategies. Proceedings of the Combustion Institute, 32(2), 2785-2792. doi:10.1016/j.proci.2008.07.031Payri, F., Pastor, J. V., Nerva, J.-G., & Garcia-Oliver, J. M. (2011). Lift-Off Length and KL Extinction Measurements of Biodiesel and Fischer-Tropsch Fuels under Quasi-Steady Diesel Engine Conditions. SAE International Journal of Engines, 4(2), 2278-2297. doi:10.4271/2011-24-0037Kook, S., & Pickett, L. M. (2012). Liquid length and vapor penetration of conventional, Fischer–Tropsch, coal-derived, and surrogate fuel sprays at high-temperature and high-pressure ambient conditions. Fuel, 93, 539-548. doi:10.1016/j.fuel.2011.10.004Settles, G. S. (2001). Schlieren and Shadowgraph Techniques. doi:10.1007/978-3-642-56640-0Pickett, L. M., Manin, J., Genzale, C. L., Siebers, D. L., Musculus, M. P. B., & Idicheria, C. A. (2011). Relationship Between Diesel Fuel Spray Vapor Penetration/Dispersion and Local Fuel Mixture Fraction. SAE International Journal of Engines, 4(1), 764-799. doi:10.4271/2011-01-0686MUSCULUS, M., & PICKETT, L. (2005). Diagnostic considerations for optical laser-extinction measurements of soot in high-pressure transient combustion environments. Combustion and Flame, 141(4), 371-391. doi:10.1016/j.combustflame.2005.01.013Williams, T. C., Shaddix, C. R., Jensen, K. A., & Suo-Anttila, J. M. (2007). Measurement of the dimensionless extinction coefficient of soot within laminar diffusion flames. International Journal of Heat and Mass Transfer, 50(7-8), 1616-1630. doi:10.1016/j.ijheatmasstransfer.2006.08.024Kook, S., & Pickett, L. M. (2011). Soot volume fraction and morphology of conventional and surrogate jet fuel sprays at 1000-K and 6.7-MPa ambient conditions. Proceedings of the Combustion Institute, 33(2), 2911-2918. doi:10.1016/j.proci.2010.05.073De Francqueville, L., Bruneaux, G., & Thirouard, B. (2010). Soot Volume Fraction Measurements in a Gasoline Direct Injection Engine by Combined Laser Induced Incandescence and Laser Extinction Method. SAE International Journal of Engines, 3(1), 163-182. doi:10.4271/2010-01-0346Musculus, M. P. B., & Kattke, K. (2009). Entrainment Waves in Diesel Jets. SAE International Journal of Engines, 2(1), 1170-1193. doi:10.4271/2009-01-1355Desantes, J. M., Pastor, J. V., García-Oliver, J. M., & Pastor, J. M. (2009). A 1D model for the description of mixing-controlled reacting diesel sprays. Combustion and Flame, 156(1), 234-249. doi:10.1016/j.combustflame.2008.10.008Idicheria, C. A., & Pickett, L. M. (2011). Ignition, soot formation, and end-of-combustion transients in diesel combustion under high-EGR conditions. International Journal of Engine Research, 12(4), 376-392. doi:10.1177/1468087411399505Aizawa, T., & Kosaka, H. (2008). Investigation of early soot formation process in a diesel spray flame via excitation—emission matrix using a multi-wavelength laser source. International Journal of Engine Research, 9(1), 79-97. doi:10.1243/14680874jer01407Bruneaux, G. (2008). Combustion structure of free and wall-impinging diesel jets by simultaneous laser-induced fluorescence of formaldehyde, poly-aromatic hydrocarbons, and hydroxides. International Journal of Engine Research, 9(3), 249-265. doi:10.1243/14680874jer0010

Firm-level technology transfer and technology cooperation for wind energy between Europe, China and India: From North–South to South–North cooperation?

For several decades the leading wind energy nations were European, while China and India were mainly the recipients of technology transfer. This paper aims to explore the role technology transfer/cooperation from Europe played in shaping firm-level wind energy technologies in China and India and to discuss whether the recent technology cooperation between the Chinese, Indian, and European wind firms challenges the classical North–South technology cooperation paradigm. The research finds that firm-level technology transfer/cooperation shaped the leading wind energy technologies in China and to a lesser extent in India. The paper also finds that several trends towards South–North technology cooperation have been observed between China, India and Europe, such as South–North flows of capital, drivers for market access, and R&D leadership, while the origins of innovation (e.g. patents) seem to remain predominantly in the global North. The paper concludes that the technology cooperation between China, India, and Europe has become more multi-faceted and increasingly Southern-led