碳减排背景下氢燃料电池船舶发展现状及监管建议

为实现碳减排目标,航运业必须寻找更为清洁环保的船舶替代燃料,而零碳排放的氢能源电池将发挥巨大潜力.在介绍氢燃料电池船舶国内应用现状和技术规范基础上,分析氢燃料电池船舶的优势和面临的挑战,最后从海事管理机构的角度提出了对氢燃料电池船舶的监管建议.     

Top-down effects and carbon flux in the ocean: A hypothesis

The close relationships between mesozooplankton, chlorophyll, and primary production normally observed across latitudes may be regarded as a bottom-up effect of increased productivity or, conversely, as a top-down effect of mesozooplankton on microzooplankton, releasing phytoplankton growth. The time-course of primary producers and mesozooplankton observed during the Late Winter Bloom in subtropical waters suggests a top-down effect, similar to the results found in lakes and mesocosm experiments. Two scenarios were observed during the development of the bloom in the Canary Island waters. The first was the increase in mesozooplankton as the effect of higher primary production due to mixing. The second scenario was the decrease in mesozooplankton due to the top-down effect of predation by diel vertical migrants upon epipelagic mesozooplankton. The structure of the food web in the euphotic zone was different depending on the presence or not of mesozooplankton, suggesting important consequences for the transport of carbon in those large areas of the ocean.     

LiOH药粒的粉尘抑制技术现状与展望

LiOH是密闭空间中一种重要的CO2吸收剂。针对LiOH药粒在使用过程中易产生刺激性粉尘的缺点,本文主要介绍了几种LiOH药粒粉尘抑制技术的技术原理,分析了各种技术的主要特点,展望了LiOH粉尘抑制技术的研究前景。     

Carbon and nutrient dynamics in a hypertrophic lagoon in southwestern Taiwan

Dissolved and particulate phases of carbon (DIC, DOC, POC) and nutrients (DIN, DIP, DSi, DON, DOP, PN) were investigated bimonthly from August 1999 to August 2000 to study biogeochemical dynamics of carbon and nutrients in Tapong Bay, a small semi-enclosed and hypertrophic lagoon in southwestern Taiwan. The lagoon has only a tidal inlet for exchanging water between Tapong Bay and Taiwan Strait, which may result in low water exchange rates and various oxygen-deficient conditions in bottom water of the inner bay during warm seasons. The water exchange time of Tapong Bay ranges from 7 days (summer) to 13 days (winter) with a mean of 10 days. Nutrient dynamics were largely ascribed to allochthonous inputs, biological and exported removals in the lagoon. Diffusion fluxes from sediments to overlying water accounted for only about 7.6% of annual DIN inputs and 1.0% of annual DIP inputs. High primary productivity (89 mol C m⁻² year⁻¹) supported by abundant nutrients primarily drove the lagoon into a hypertrophic condition as particulate organic matter was derived mainly from biological production. Excess of DIP appeared to occur throughout the study period in the lagoon. Temperature, solar radiation and turbidity, rather than nutrients, perhaps controlled seasonal variations of primary productivity. The net ecosystem production (NEP) derived from daily changes of DOC and POC inventories was about 6.3 mmol C m⁻² day⁻¹ that was close to 6.7 mmol C m⁻² day⁻¹ simulated from the biogeochemical modeling. Therefore, the net ecosystem production (NEP) rate of organic carbon estimated from the biogeochemical model was reliable, and the NEP was temporally variable with an annual mean of 5.8 mol C m⁻² year⁻¹, implying that Tapong Bay was an autotrophic system. Although calcification proceeded pronouncedly in warm seasons, an invasion of CO₂ was significant in this system. In terms of nitrogen budget, the annual nitrogen fixation exceeded the annual denitrification with a magnitude of 1.30 mol N m⁻² year⁻¹, which may be supported by the abundance of nitrogen fixation microplanktons in the lagoon.     

基于营运数据的船舶能效分析及预测

为应对航运业日益严苛的温室气体减排要求,提出一种计算船舶实际营运性能的方法,并基于该方法实现对营运能效的分析和预测。以某大型集装箱船为研究对象,对其在2021年前2个月的营运数据进行分析。结果表明：该船的实际性能相比设计值降低约11.2%,通过采取坞修和调整船舶营运工况等措施能有效提高船舶的营运能效指数;通过对该船的营运能效进行预测,可给出提高船舶碳排放强度等级的具体措施,为船舶能效管理计划的制订提供参考。     

Air transportation in a carbon constrained world: Long-term dynamics of policies and strategies for mitigating the carbon footprint of commercial aviation

With increasing demand for air transportation worldwide and decreasing marginal fuel efficiency improvements, the contribution of aviation to climate change relative to other sectors is projected to increase in the future. As a result, growing public and political pressures are likely to further target air transportation to reduce its greenhouse gas emissions. The key challenges faced by policy makers and air transportation industry stakeholders is to reduce aviation greenhouse gas emissions while sustaining mobility for passengers and time-sensitive cargo as well as meeting future demand for air transportation in developing and emerging countries. This paper examines five generic policies for reducing the emissions of commercial aviation; (1) technological efficiency improvements, (2) operational efficiency improvements, (3) use of alternative fuels, (4) demand shift and (5) carbon pricing (i.e. market-based incentives). In order to evaluate the impacts of these policies on total emissions, air transport mobility, airfares and airline profitability, a system dynamics modeling approach was used. The Global Aviation Industry Dynamics (GAID) model captures the systemic interactions and the delayed feedbacks in the air transportation system and allows scenarios testing through simulations. For this analysis, a set of 34 scenarios with various levels of aggressiveness along the five generic policies were simulated and tested. It was found that no single policy can maintain emissions levels steady while increasing projected demand for air transportation. Simulation results suggest that a combination of the proposed policies does produce results that are close to a “weak” sustainability definition of increasing supply to meet new demand needs while maintaining constant or increasing slightly emissions levels. A combination of policies that includes aggressive levels of technological and operations efficiency improvements, use of biofuels along with moderate levels of carbon pricing and short-haul demand shifts efforts achieves a 140% increase in capacity in 2024 over 2004 while only increasing emissions by 20% over 2004. In addition, airline profitability is moderately impacted (10% reduction) compared to other scenarios where profitability is reduced by over 50% which pose a threat to necessary investments and the implementation of mitigating measures to reduce CO2 emissions. This study has shown that an approach based on a portfolio of mitigating measures and policies spanning across technology and operational improvements, use of biofuels, demand shift and carbon pricing is required to transition the air transportation industry close to an operating point of environmental and mobility sustainability.     

Development of a corrected average speed model for calculating carbon dioxide emissions per link unit on urban roads

The purpose of our study is to develop a “corrected average emission model,” i.e., an improved average speed model that accurately calculates CO₂ emissions on the road. When emissions from the central roads of a city are calculated, the existing average speed model only reflects the driving behavior of a vehicle that accelerates and decelerates due to signals and traffic. Therefore, we verified the accuracy of the average speed model, analyzed the causes of errors based on the instantaneous model utilizing second-by-second data from driving in a city center, and then developed a corrected model that can improve the accuracy. We collected GPS data from probe vehicles, and calculated and analyzed the average emissions and instantaneous emissions per link unit. Our results showed that the average speed model underestimated CO₂ emissions with an increase in acceleration and idle time for a speed range of 20 km/h and below, which is the speed range for traffic congestion. Based on these results, we analyzed the relationship between average emissions and instantaneous emissions according to the average speed per link unit, and we developed a model that performed better with an improved accuracy of calculated CO₂ emissions for 20 km/h and below.     

Assessment of carbon emission costs for air cargo transportation

This study presents a set of models that calculate carbon emissions in individual phases of flight during air cargo transportation, investigates resultant carbon footprints by aircraft type and flight route, and estimates increases in transportation costs for airlines due to carbon taxes imposed by the EU ETS. The estimated results provide useful references for airlines in aircraft assignment on different routes and in aircraft selection for new purchases. Validation of the model is conducted by simulating the potential impact of the implementation of the EU ETS on costs of air cargo transportation for six routes and six types of aircraft. Results show that the impact may be subject to various factors including unit carbon emissions per aircraft, aviation emission allowances per airline, and carbon trading prices; and that increases in costs of air cargo transportation range from 0% to 5.27% per aircraft per route. Therefore, the implementation of the EU ETS may encourage airlines to cut down their operating costs by reducing their carbon emissions, thereby ameliorating greenhouse gas pollution caused by air cargo transportation.     

The role of ‘indirect’ greenhouse gas emissions in tourism: Assessing the hidden carbon impacts from a holiday package tour

Tourism is a noticeable contributor to global greenhouse gas (GHG) emissions. Existing estimates of tourism’s carbon footprint are however incomplete as they fail to holistically assess the additional, ‘indirect’ carbon requirements. These arise from the non-use phases of a tourism product or service life cycle and can be further magnified by supply chain industries. Under-development of methods for carbon impact assessment in tourism is the primary reason for the omission of ‘indirect’ GHG emissions. This study develops a new approach for comprehensive appraisal of GHG emissions which incorporates and advances the methodological advantages of existing assessment techniques. It tests the applicability of this approach in tourism by conducting a holistic analysis of a standard holiday package to Portugal, based on the British tourism market. The new approach demonstrates the significance of the ‘indirect’ GHG emissions in the total carbon footprint from the holiday package, thus emphasising the necessity for more comprehensive future assessments.     

Help or hindrance? The travel,energy and carbon impacts of highly automated vehicles

Experts predict that new automobiles will be capable of driving themselves under limited conditions within 5–10 years, and under most conditions within 10–20 years. Automation may affect road vehicle energy consumption and greenhouse gas (GHG) emissions in a host of ways, positive and negative, by causing changes in travel demand, vehicle design, vehicle operating profiles, and choices of fuels. In this paper, we identify specific mechanisms through which automation may affect travel and energy demand and resulting GHG emissions and bring them together using a coherent energy decomposition framework. We review the literature for estimates of the energy impacts of each mechanism and, where the literature is lacking, develop our own estimates using engineering and economic analysis. We consider how widely applicable each mechanism is, and quantify the potential impact of each mechanism on a common basis: the percentage change it is expected to cause in total GHG emissions from light-duty or heavy-duty vehicles in the U.S. Our primary focus is travel related energy consumption and emissions, since potential lifecycle impacts are generally smaller in magnitude. We explore the net effects of automation on emissions through several illustrative scenarios, finding that automation might plausibly reduce road transport GHG emissions and energy use by nearly half – or nearly double them – depending on which effects come to dominate. We also find that many potential energy-reduction benefits may be realized through partial automation, while the major energy/emission downside risks appear more likely at full automation. We close by presenting some implications for policymakers and identifying priority areas for further research.