Incorporation of LNG into Small Gas Networks via FSRUs

Geopolitical risks on pipeline gas imports, increasing natural gas demand and the need to ensure continuous power supply with ever increasing fluctuating renewable power generation require diversification of gas sources to ensure supply security. With the global liquefied natural gas (LNG) trade increasing every year and natural gas prices remaining relatively low, more and more countries are interested in investing in regasification infrastructure. Establishing a floating storage and regasification unit (FSRU) and importing LNG has several advantages: lower cost compared to an onshore terminal, flexibility in relocation and the availability of short-term contracts all of which help serve small markets. FSRUs can also be operated in standby mode or used as an LNG storage facility. Operating an FSRU as a storage facility while beneficial for small networks introduces the challenges of LNG weathering and managing of the boil-off gas (BOG). To investigate these challenges on operation, a mathematical model is developed to determine the boil-off rate (BOR) over various time frames. The initial BOR is 0.129% of the initial storage volume increased to 0.143% after 10 weeks. Subsequent use of Aspen HYSYS to determine the change in LNG composition determined that Wobbe Index (WI) of the LNG varied from 51.58 to 51.616 MJ/Nm3 after 10 weeks of storage. An annual economic estimation of operating FSRU as a storage facility was carried out determining that the per unit price of gas obtained from regasified LNG is at least 42% lower than the current per unit price of gas in Ireland

Synthetic Natural Gas Production: Production Cost, Key Cost Factors and Optimal Configuration

The volatile nature of the renewable energy sources requires energy storage to compensate for the imbalances and to provide reliable base load. Power-to-Methane technology facilitates long-term high capacity renewable energy storage in the form of Synthetic Natural Gas (SNG) in the gas network. Unlike hydrogen, SNG usage in the network has no restrictions and natural gas appliances can operate on SNG. The two inputs required to produce SNG in the methanator are hydrogen and CO2 and they can be obtained from several sources. This leads to multiple possible process flow configurations in SNG production, each of them with varying performance. An optimization model has been developed in GAMS to analyse the performance of these various configurations. The objective of this research is to determine the optimal configuration, key cost factors and their effects on the production cost to identify the areas that require further development for cost reduction. This work also aims to determine the production cost per unit of SNG and the factors with most significant influence on the production cost by implementing a factorial design and a multivariate analysis (analysis of variance) approach. Methanator, electrolyser, biogas upgrader and hydrogen storage are considered as the fundamental process units in this work. The lowest production cost identified in the first year of production is 0.432 €/kWhSNG. The discounted production cost obtained shows that the lowest cost in 20 years from now is 0.143 €/kWhSNG. The variable with the most influence on the production cost is the capex of the methanator followed by the capacity of the methanator

Dungeness crab fishermen perceptions of injury causation and factors in staying safe

Background: Commercial fishing is a hazardous occupation in the United States (US). Injury surveillance data relies heavily on US Coast Guard reports, which capture injuries severe enough to require reporting. The reports do not incorporate the fishermen’s perspective on contributing factors to injuries and staying safe while fishing.  Materials and methods: We conducted a pre-season survey of Dungeness crab fishermen during 2015 to 2016. Community researchers administered surveys to fishermen. Respondents reported their opinions about factors contributing to injuries and staying safe, which were grouped into similar themes by consen- sus. Descriptive statistics were calculated to explore the number of injuries, crew position, age, and years of experience. Chi-square tests compared perceptions of injury causation, staying safe, and other factors.  Results: Four hundred twenty-six surveys were completed. Injury causation perceptions were sorted into 17 categories, and staying safe perceptions were sorted into 13 categories. The most frequently cited causes of injury were heavy workload (86, 21.9%), poor mental focus (78, 19.9%), and inexperience (56, 14.3%). The most frequently cited factors in staying safe while fishing were awareness (142, 36.1%), good and well-maintained fishing gear/vessel (41, 10.4%), and best marine practices (39, 9.9%). Opinions were not significantly associated with experiencing an injury in the past while fishing, but some opinions were significantly associated with crew position, age, and years of experience.  Conclusions: The perceptions of fishermen can be evaluated further and incorporated into training or intervention development. The fishermen-led approach of this project lends itself to developing injury pre- vention strategies that are effective, realistic and suitable. The resources available at FLIPPresources.org, such as informational sheets for new fishermen, sample crew agreements, and first aid kit resources, supply workers in this fishery with real solutions for issues they identified through their survey responses.

Injury Risk Perception of Commercial Dungeness Crab Fishermen

The Fishermen Led Injury Prevention Program is the first and only research focused on non-fatal injury prevention among commercial fishermen. • No fishermen reported that they had zero chance of injury, regardless of injuries sustained in career and/or in the past year. • Fishermen who have sustained an injury in their career and/or in the past year, have a higher perception of injury risk. • There is no connection between a fisherman’s history with injury and the amount they worry about sustaining an injury.• Commercial fishing is one of the most dangerous professions in the United States. • Between 2002-2014 Dungeness crab fishermen had 209 fatalities per 100,000 full-time equivalent workers. • 405 surveys were collected by community researchers before the 2015-2016 Dungeness crab season. • We examine here the association of injury and risk perception