Robustness of Trans-European Gas Networks

Here we uncover the load and fault-tolerant backbones of the trans-European gas pipeline network. Combining topological data with information on inter-country flows, we estimate the global load of the network and its tolerance to failures. To do this, we apply two complementary methods generalized from the betweenness centrality and the maximum flow. We find that the gas pipeline network has grown to satisfy a dual-purpose: on one hand, the major pipelines are crossed by a large number of shortest paths thereby increasing the efficiency of the network; on the other hand, a non-operational pipeline causes only a minimal impact on network capacity, implying that the network is error-tolerant. These findings suggest that the trans-European gas pipeline network is robust, i.e., error tolerant to failures of high load links.Comment: 11 pages, 8 figures (minor changes

Magnetic bearing turbomachinery case histories and applications for space related equipment

The concept of magnetic levitation is not a new one and can be easily traced back to the 1800's. It is only recently, however, that the congruous technologies of electronic control systems, power electronics, and magnetic materials have begun to merge to make the magnetic suspension device a viable product. A brief overview of an active magnetic bearing technology is provided. Case histories of various turbomachinery in North America presently operating on magnetic bearings are reviewed. Finally, projections are made as to the space related machinery that may be benefited by incorporating magnetic bearings into the equipment design

Investigating new accident causation, risk assessment, and mitigation strategy selection tools in the petroleum industry

The inherent complexity of the processes and the volatile nature of petroleum products compel the petroleum industry to continually seek and develop tools and techniques to identify, evaluate, and mitigate potential risks that can negatively impact their process operations. Additionally, government agencies and nonprofit professional societies guide the petroleum industry with regulatory guidelines, standards, and recommended best practices. The industry and these agencies and societies work to improve operational management, to ensure safe working conditions, and to minimize risk of all kinds, so that if failures occur, damage is contained within tolerable limits (Health and Safety Executives, 2013). The currently used of both qualitative and quantitative risk assessment tools fall short in identifying and ranking potential risks in the petroleum industry and they fail to demonstrate that risks have been reduced as low as reasonably practicable (ALARP) (Fitzgerald, 2004, p. 3). Moreover, the tools are limited to large, complex, and expensive studies (Fitzgerald, 2004, p. 3). Because accidents due to both human errors and electromechanical failures still occur and result in various consequences, critics have raised concerns about the petroleum industry\u27s safety and risk mitigation credentials and question its ability to prevent major accidents. The purpose of this research is to introduce new methods that provide more detailed and structure information to decision makers. They are more robust and easier-to-use so that novice engineers can successfully apply them without experts\u27 need. This dissertation employs the publication option, where the research results are reported by presenting the text of five journal-conference publications. --Abstract, page iv

Hydrogen and fuel cell technologies for heating: A review

The debate on low-carbon heat in Europe has become focused on a narrow range of technological options and has largely neglected hydrogen and fuel cell technologies, despite these receiving strong support towards commercialisation in Asia. This review examines the potential benefits of these technologies across different markets, particularly the current state of development and performance of fuel cell micro-CHP. Fuel cells offer some important benefits over other low-carbon heating technologies, and steady cost reductions through innovation are bringing fuel cells close to commercialisation in several countries. Moreover, fuel cells offer wider energy system benefits for high-latitude countries with peak electricity demands in winter. Hydrogen is a zero-carbon alternative to natural gas, which could be particularly valuable for those countries with extensive natural gas distribution networks, but many national energy system models examine neither hydrogen nor fuel cells for heating. There is a need to include hydrogen and fuel cell heating technologies in future scenario analyses, and for policymakers to take into account the full value of the potential contribution of hydrogen and fuel cells to low-carbon energy systems

Financial viability of offshore wind on the Texas Gulf Coast

Offshore wind is already a significant component of the electricity generation mix in Europe, and improvements in technology and cost are enabling increased offshore wind penetration in new markets around the world. Thus far, the US has struggled to materially participate in this industry, with only a single 30 MW offshore project in operation. Navigating a complicated regulatory framework, the lack of a coherent national policy, and facing local opposition, the industry has experienced some spectacular failures in recent years. However, the US now has an opportunity to take advantage of the lessons learned from years of (primarily) European development and combine them with excellent offshore wind resources close to transmission-constrained load centers. By far the leader of the US onshore wind industry, and with a long history of offshore oil and gas development, Texas has some major advantages when it comes to offshore wind. Wind resources in the Gulf of Mexico are more than adequate for economic production. With shallow depths and relatively calm seas, the Texas Gulf Coast is also well suited to offshore wind construction. These factors, coupled with a pro-development state regulatory scheme and extended jurisdiction over submerged lands, suggest that Texas is an ideal candidate for offshore wind development. With no currently active projects in the pipeline, this thesis examines the economic viability of offshore wind development on the Texas Gulf Coast at the project level. Using an ideal location and cost data from National Renewable Energy Laboratory (NREL), the Energy Information Administration (EIA), and industry sources, a hypothetical “test project” was developed and evaluated against three cost estimate cases and ten regulatory scenarios. These inputs were fed into a Discounted Cash Flow model to determine potential competitiveness in the Power Purchase Agreement (PPA) market in the ERCOT region. Results indicate that without significant cost reductions or major changes to either market conditions or federal/state incentive schemes, Texas Gulf Coast offshore wind cannot compete with other forms of onshore renewable generation. With ever-decreasing costs, it is not impossible that offshore wind could become viable at some point in the future, but given current conditions, it is not likely that any projects are on the near-term horizon.Energy and Earth Resource

Effect of flow pattern at pipe bends on corrosion behaviour of low carbon steek and its challenges

Recent design work regarding seawater flow lines has emphasized the need to identify, develop, and verify critical relationships between corrosion prediction and flow regime mechanisms at pipe bend. In practice this often reduces to an pragmatic interpretation of the effects of corrosion mechanisms at pipe bends. Most importantly the identification of positions or sites, within the internal surface contact areas where the maximum corrosion stimulus may be expected to occur, thereby allowing better understanding, mitigation, monitoring and corrosion control over the life cycle. Some case histories have been reviewed in this context, and the interaction between corrosion mechanisms and flow patterns closely determined, and in some cases correlated. Since the actual relationships are complex, it was determined that a risk based decision making process using selected ‘what’ if corrosion analyses linked to ‘what if’ flow assurance analyses was the best way forward. Using this in methodology, and pertinent field data exchange, it is postulated that significant improvements in corrosion prediction can be made. This paper outlines the approach used and shows how related corrosion modelling software data such as that available from corrosion models Norsok M5006, and Cassandra to parallel computational flow modelling in a targeted manner can generate very noteworthy results, and considerably more viable trends for corrosion control guidance. It is postulated that the normally associated lack of agreement between corrosion modelling and field experience, is more likely due to inadequate consideration of corrosion stimulating flow regime data, rather than limitations of the corrosion modelling. Applications of flow visualization studies as well as computations with the k-ε model of turbulence have identified flow features and regions where metal loss is a maximu

Next Steps for Hydrogen - physics, technology and the future

Hydrogen has been proposed as a future energy carrier for more than 40 years. In recent decades, impetus has been given by the need to reduce global greenhouse gas emissions from vehicles. In addition, hydrogen has the potential to facilitate the large-scale deployment of variable renewables in the electricity system. Despite such drivers, the long-anticipated hydrogen economy is proving to be slow to emerge. This report stresses the role that physics and physics-based technology could play in accelerating the large-scale deployment of hydrogen in the energy system. Emphasis is given to the potential of cryogenic liquid hydrogen and the opportunities afforded by developments in nanoscience for hydrogen storage and use. The use of low-temperature liquid hydrogen opens up a technological opportunity separate from, but complementary with, energy applications. The new opportunity is the ability to cool novel materials into the superconducting state without the need to use significant quantities of expensive liquid helium. Two of the authors have previously coined the term “hydrogen cryomagnetics” for when liquid hydrogen is utilised in high-field and high-efficiency magnets. The opportunity for liquid hydrogen to displace liquid helium may be a relatively small business opportunity compared to global transport energy demands, but it potentially affords an opportunity to kick-start the wider commercial use of hydrogen. The report considers various important factors shaping the future for hydrogen, such as competing production methods and the importance of safety, but throughout it is clear that science and engineering are of central importance to hydrogen innovation and physics has an important role to play