Uncertainty quantification of CO2 emission reduction for maritime shipping

The International Maritime Organization (IMO) has recently proposed several operational and technical measures to improve shipping efficiency and reduce the greenhouse gases (GHG) emissions. The abatement potentials estimated for these measures have been further used by many organizations to project future GHG emission reductions and plot Marginal Abatement Cost Curves (MACC). However, the abatement potentials estimated for many of these measures can be highly uncertain as many of these measures are new, with limited sea trial information. Furthermore, the abatements obtained are highly dependent on ocean conditions, trading routes and sailing patterns. When the estimated abatement potentials are used for projections, these ‘input’ uncertainties are often not clearly displayed or accounted for, which can lead to overly optimistic or pessimistic outlooks. In this paper, we propose a methodology to systematically quantify and account for these input uncertainties on the overall abatement potential forecasts. We further propose improvements to MACCs to better reflect the uncertainties in marginal abatement costs and total emissions. This approach provides a fuller and more accurate picture of abatement forecasts and potential reductions achievable, and will be useful to policy makers and decision makers in the shipping industry to better assess the cost effective measures for CO₂ emission reduction.     

Investigation on the decarbonization of shipping: An approach to hydrogen and ammonia

Global warming and greenhouse gas emissions are today's major challenges for sustainable industrial developments, and shipping is an important key element of the industrial chain. However, maritime transportation is responsible for 3.1% of total CO₂ emissions worldwide, and International Maritime Organization estimates that it will continue to increase if no measure is taken. In this perspective, alternative fuels are promising solutions to reach the zero-carbon shipping aim. This paper investigates zero-carbon fuels and their power generation solutions to eliminate ship-sourced CO₂ emissions. Hydrogen and ammonia are analyzed to use in a fuel cell according to five different criteria: safety, cost, storage, sustainability, and environmental impact. Criteria weightings are found according to expert points by using the analytic hierarchy process. While the safety and environmental impacts have a major effect on the results, sustainability, storage, and cost are lined up, respectively. A final comparison table is formed by changing weightings for each criterion regarding maritime industry conditions. Sensitivity analysis of the results is carried out with different scenarios to show the reliability of the handled analysis. As a result, ammonia is marginally showed better performance against hydrogen for shipping with applied criteria in this work. This study highlights that shipping has strong options such as ammonia and hydrogen on the road of decarbonization and ammonia can play an important role in the transition to zero-carbon shipping.     

Greenhouse gas emissions from the international maritime transport of New Zealand's imports and exports

Greenhouse gas emissions from international maritime transport are exempt from liabilities under the Kyoto Protocol. Research into quantifying these emissions is ongoing, and influences policy proposals to reduce emissions. This paper presents a cargo-based analysis of fuel consumption and greenhouse gas emissions from New Zealand's international maritime transport of goods. Maritime transport moves 99.5% (by mass) of New Zealand's internationally traded products. It is estimated that 73% of visiting vessels' activity can be directly attributed to the movement of goods in and out of New Zealand. A cargo-based methodology was used to estimate that the international maritime transport of New Zealand's imports and exports consumed 2.5 million tonnes (Mt; 2.6 billion litres) of fuel during the year 2007, which generated 7.7 Mt of carbon dioxide (CO₂) emissions. Double-counting of emissions would occur if a similar method was applied to all New Zealand's trading partners. In contrast, since few large vessels refuel in New Zealand, the National Greenhouse Gas Inventory listed 2007 international maritime transportation emissions as 0.98 Mt of CO₂, calculated from fuel bunkered for international transport. The results, therefore, show a significant difference between activity-based and bunker-fuel methodologies in quantifying New Zealand's emissions. International policy implications are discussed.     

Shore Side Electricity in Europe: Potential and environmental benefits

In the context of reducing emissions from the transport sector, the EU Commission envisions a strong modal shift to energy efficient modes including maritime shipping and inland shipping, as an alternative for road transport. In view of the expected growth of the sector, the emissions from waterborne transport are a key concern. When at berth, ships typically use their auxiliary engines to generate electrical power for communications, lighting, ventilation and other on-board equipment. The extended use of vessels’ auxiliary engines augments greenhouse gas (GHG) emissions and air pollution in the adjacent ports, which are typically located in or near densely populated areas, thus leading to dangerous health and environmental effects. Shore Side Electricity (SSE) is an option for reducing the unwanted environmental impacts of ships at berth, i.e. GHG emissions, other air pollutants (NO_x, SO_x, PM) and noise of ships using their auxiliary engines. This paper quantifies the economic and environmental potential for SSE in Europe, through detailed estimation of in-port ships’ emissions and relevant energy demand, providing an insight of the expected barriers for implementation and formulating recommendations on policy actions that could accelerate the implementation of SSE in European harbors.     

Applying California's AB 32 targets to the regional level: A study of San Diego County greenhouse gases and reduction strategies

This paper presents a summary of a local effort in California to assess greenhouse gas (GHG) emissions and identify potential mitigation measures. Local policymakers in California already have been searching for ways to reduce GHG emissions but it was the California Global Warming Solutions Act of 2006 (AB 32), which seeks to reduce GHG emissions to 1990 levels by 2020, that has provided a framework for regions to evaluate their ability to reduce GHG emissions. We conducted a GHG inventory for the San Diego region from 1990 to 2006, with forecasts to 2020. The region emitted approximately 34 million metric tons of carbon dioxide equivalent (MMT CO₂E) in 2006 from anthropogenic sources, which represents a 17% increase over the 1990 level of 29 MMT CO₂E. Applying a combination of 21 existing or pending state GHG reduction mandates and feasible regional measures we show that the region could achieve the AB 32 target. Although the largest reductions are achieved through state mandates, all measures, including at the local level, will be required to achieve the AB 32 target. Thus local regions retain control over a fairly significant portion of reductions, and remain important actors in the implementation and compliance of state mandates.     

Analysis of policies to reduce oil consumption and greenhouse-gas emissions from the US transportation sector

Even as the US debates an economy-wide CO₂ cap-and-trade policy the transportation sector remains a significant oil security and climate change concern. Transportation alone consumes the majority of the US’s imported oil and produces a third of total US Greenhouse-Gas (GHG) emissions. This study examines different sector-specific policy scenarios for reducing GHG emissions and oil consumption in the US transportation sector under economy-wide CO₂ prices. The 2009 version of the Energy Information Administration’s (EIA) National Energy Modeling System (NEMS), a general equilibrium model of US energy markets, enables quantitative estimates of the impact of economy-wide CO₂ prices and various transportation-specific policy options. We analyze fuel taxes, continued increases in fuel economy standards, and purchase tax credits for new vehicle purchases, as well as the impacts of combining these policies. All policy scenarios modeled fail to meet the Obama administration’s goal of reducing GHG emissions 14% below 2005 levels by 2020. Purchase tax credits are expensive and ineffective at reducing emissions, while the largest reductions in GHG emissions result from increasing the cost of driving, thereby damping growth in vehicle miles traveled.     

Energy balance and GHG-abatement cost of cassava utilization for fuel ethanol in Thailand

Since 2001, in order to enhance ethanol's cost competitiveness with gasoline, the Thai government has approved the exemption of excise tax imposed on ethanol, controlling the retail price of gasohol (a mixture of ethanol and gasoline at a ratio of 1:9) to be less than that of octane 95 gasoline, within a range not exceeding 1.5 baht a litre. The policy to promote ethanol for transport is being supported by its positive effects on energy security and climate change mitigation. An analysis of energy, greenhouse gas (GHG) balances and GHG abatement cost was done to evaluate fuel ethanol produced from cassava in Thailand. Positive energy balance of 22.4 MJ/L and net avoided GHG emission of 1.6 kg CO₂ eq./L found for cassava-based ethanol (CE) proved that it would be a good substitute for gasoline, effective in fossil energy saving and GHG reduction. With a GHG abatement cost of US$99 per tonne of CO₂, CE is rather less cost effective than the many other climate strategies relevant to Thailand in the short term. Opportunities for improvements are discussed to make CE a reasonable option for national climate policy.     

Modeling California policy impacts on greenhouse gas emissions

This paper examines policy and technology scenarios in California, emphasizing greenhouse gas (GHG) emissions in 2020 and 2030. Using CALGAPS, a new, validated model simulating GHG and criteria pollutant emissions in California from 2010 to 2050, four scenarios were developed: Committed Policies (S1), Uncommitted Policies (S2), Potential Policy and Technology Futures (S3), and Counterfactual (S0), which omits all GHG policies. Forty-nine individual policies were represented. For S1–S3, GHG emissions fall below the AB 32 policy 2020 target [427 million metric tons CO₂ equivalent (MtCO₂e) yr⁻¹], indicating that committed policies may be sufficient to meet mandated reductions. In 2030, emissions span 211–428 MtCO₂e yr⁻¹, suggesting that policy choices made today can strongly affect outcomes over the next two decades. Long-term (2050) emissions were all well above the target set by Executive Order S-3-05 (85 MtCO₂e yr⁻¹); additional policies or technology development (beyond the study scope) are likely needed to achieve this objective. Cumulative emissions suggest a different outcome, however: due to early emissions reductions, S3 achieves lower cumulative emissions in 2050 than a pathway that linearly reduces emissions between 2020 and 2050 policy targets. Sensitivity analysis provided quantification of individual policy GHG emissions reduction benefits.     

Scenario analysis of the energy demand and CO<Subscript>2</Subscript> emission reduction potential of the urban transport system of Beijing through 2030

An assessment of the energy demand and the potential for sector-based emission reductions will provide necessary background information for policy makers. In this paper, Beijing was selected as a special case for analysis in order to assess the energy demand and potential of CO₂ abatement in the urban transport system of China. A mathematical model was developed to generate three scenarios for the urban transport system of Beijing from 2010 to 2030. The best pattern was identified by comparing the three different scenarios and assessing their urban traffic patterns through cost information. Results show that in the high motorization-oriented pattern scenario, total energy demand is about 13.94% higher, and the average CO₂ abatement per year is 3.38 million tons less than in the reference scenario. On the other hand, in the bus and rail transit-oriented scenario, total energy demand is about 11.57% less, and the average CO₂ abatement is 2.8 million tons more than in the reference scenario. Thus, Beijing cannot and should not follow the American pattern of high motorization-oriented transport system but learn from the experience of developed cities of Europe and East Asia.     

Scenario analysis of the energy demand and CO2 emission reduction potential of the urban transport system of Beijing through 2030

An assessment of the energy demand and the potential for sector-based emission reductions will provide necessary background information for policy makers. In this paper, Beijing was selected as a special case for analysis in order to assess the energy demand and potential of CO₂ abatement in the urban transport system of China. A mathematical model was developed to generate three scenarios for the urban transport system of Beijing from 2010 to 2030. The best pattern was identified by comparing the three different scenarios and assessing their urban traffic patterns through cost information. Results show that in the high motorization-oriented pattern scenario, total energy demand is about 13.94% higher, and the average CO₂ abatement per year is 3.38 million tons less than in the reference scenario. On the other hand, in the bus and rail transit-oriented scenario, total energy demand is about 11.57% less, and the average CO₂ abatement is 2.8 million tons more than in the reference scenario. Thus, Beijing cannot and should not follow the American pattern of high motorization-oriented transport system but learn from the experience of developed cities of Europe and East Asia.     

ACROPOLIS: An example of international collaboration in the field of energy modelling to support greenhouse gases mitigation policies

Energy models are considered as valuable tools to assess the impact of various energy and environment policies. The ACROPOLIS initiative, supported by the European Commission and the International Energy Agency, used up to 15 energy models to simulate and evaluate selected policy measures and instruments and then compare their impacts on energy systems essentially in terms of costs of greenhouse gas emissions (GHG) reduction and energy technology choice. Four case studies are formulated considering policies and measures on renewable portfolio schemes and internationally tradable green certificates, emissions trading and global GHG abatement target, energy efficiency standards and internalisation of external costs. The main focus of the project is on the electricity sector. From a large set of quantified results, ACROPOLIS provides an international scientific consensus, on some key issues, which could be useful in assessing and designing energy and environment policies at the world, European and national/regional levels. It concludes that the Kyoto targets (and their continuation beyond 2010 in specific scenarios) could be achieved at a cost around 1% of GDP through global emissions trading, indicating also that this flexibility mechanism is a more cost-effective instrument for GHG mitigation than meeting the goal domestically without trade. It demonstrates that internalising external costs through a price increase reduces local pollutants (SO_x, NO_x, and others) and it produces other benefits such as triggering the penetration of clean technologies in addition to the curbing of CO₂ emissions.     

Should a vehicle fuel economy standard be combined with an economy-wide greenhouse gas emissions constraint? Implications for energy and climate policy in the United States

The United States has adopted fuel economy standards that require increases in the on-road efficiency of new passenger vehicles, with the goal of reducing petroleum use and (more recently) greenhouse gas (GHG) emissions. Understanding the cost and effectiveness of fuel economy standards, alone and in combination with economy-wide policies that constrain GHG emissions, is essential to inform coordinated design of future climate and energy policy. We use a computable general equilibrium model, the MIT Emissions Prediction and Policy Analysis (EPPA) model, to investigate the effect of combining a fuel economy standard with an economy-wide GHG emissions constraint in the United States. First, a fuel economy standard is shown to be at least six to fourteen times less cost effective than a price instrument (fuel tax) when targeting an identical reduction in cumulative gasoline use. Second, when combined with a cap-and-trade (CAT) policy, a binding fuel economy standard increases the cost of meeting the GHG emissions constraint by forcing expensive reductions in passenger vehicle gasoline use, displacing more cost-effective abatement opportunities. Third, the impact of adding a fuel economy standard to the CAT policy depends on the availability and cost of abatement opportunities in transport—if advanced biofuels provide a cost-competitive, low carbon alternative to gasoline, the fuel economy standard does not bind and the use of low carbon fuels in passenger vehicles makes a significantly larger contribution to GHG emissions abatement relative to the case when biofuels are not available. This analysis underscores the potentially large costs of a fuel economy standard relative to alternative policies aimed at reducing petroleum use and GHG emissions. It further emphasizes the need to consider sensitivity to vehicle technology and alternative fuel availability and costs as well as economy-wide responses when forecasting the energy, environmental, and economic outcomes of policy combinations.     

Robust MACCs? The topography of abatement by fuel switching in the European power sector

This paper employs a simulation model of the European power sector to analyze the abatement response to a CO₂ price through fuel switching, one of principal means of reducing greenhouse gas emissions in any economy. Abatement is shown to depend not only on the price of allowances, but also and more importantly on the load level of the system and the ratio between natural gas and coal prices. The interplay of these different determinants vitiates any simple relation between a CO₂ price and abatement and requires the development of more than two-dimensional graphics to illustrate these complex relationships. In the terms of the literature on the use of marginal abatement cost curves (MACCs), we find that these MACCs are not robust as usually defined and we suggest that the more complex topography developed in this paper may be more helpful in visualizing this abatement response to a CO₂ price.     

An innovative indicator of carbon dioxide emissions for developing countries: A study of Taiwan

Ever since the Kyoto Protocol entered into force, the issues of climate change and greenhouse gas (GHG) emissions have drawn more and more attention globally. However, the major concern of the Kyoto Protocol to reduce the overall GHG emissions might be inaccessible for most developing countries, which rely heavily on the energy-intensive industries for exports and economic growth. In this study, an innovative indicator of net carbon dioxide (CO₂) emissions, which excludes the emissions corresponding to the exports, is proposed to explicitly reveal domestic situations of developing countries. By introducing the indicator of net CO₂ emissions to top five energy-intensive industries in Taiwan, the analysis indicates that the increase in CO₂ emissions from 1999 to 2004 is mostly contributed by the expanded exports rather than the domestic demand. The distinct growth patterns of the apparent and net CO₂ emissions also imply the transformation of the industrial sector. It is expected that, for developing countries, the concept of net emissions may not only serve as a proper interim target during the process of international negotiations over GHG reductions but also highlights the prominence of addressing the emissions from the industrial sector as the top priority.     

Possible impact of the Renewable Energy Directive on N fertilization intensity and yield of winter oilseed rape in different cropping systems

In 2009, the Renewable Energy Directive (RED), established sustainability criteria for biofuels including legal thresholds for specific greenhouse gas (GHG) emissions, expressed as g CO₂eq per MJ of biofuel. Because biofuels are a major market for winter oilseed rape (WOSR), investigating the possible impact of the RED on WOSR cropping practices is prudent. This study analyses GHG emissions for WOSR cropping practices (namely N fertilization intensity, tillage method and crop rotation) basing on a 6-year field trial in a high yielding area of northern Germany. Using the International Panel on Climate Change (IPCC) methodology the field emissions of nitrous oxide (N₂O) are calculated from the nitrogen (N) inputs to the cropping system.Results showed that the predominant source of GHG emissions is the N related emissions from production of fertilizer and N₂O field emissions. Specific GHG emissions are lowest without N fertilizer but rise continuously with increasing N rates. Yield per ha also responded to N fertilization resulting in lowered acreage productivity when reducing GHG emissions by reducing N fertilization level. Most calculated scenarios and cropping systems result in a drastic decrease of N fertilization to achieve thresholds, causing substantial yield losses. To a certain extent, the required drastic reduction of N fertilization in some scenarios is driven by using the IPCC methodology for calculating N₂O emissions. Therefore characteristics of this methodology are also discussed within this study. To mitigate the impact of the RED on WOSR, peas (legumes) may be a possible preceding crop to WOSR.     

A comparison of avoided greenhouse gas emissions when using different kinds of wood energy

In this study, micro-level data from wood energy producers in Hedmark County were gathered and analysed. The aim was to find how much greenhouse gas (GHG) emissions various kinds of wood energy cause (not only CO₂, but also CH₄ and N₂O), which energy they substitute, their potential to reduce GHG emissions, and the major sources of uncertainty. The method was life cycle assessment. Six types of wood energy were studied: fuel wood, sawdust, pellets, briquettes, demolition wood, and bark.GHG emissions over the life cycle of the wood energy types in this study are 2–19% of the emissions from a comparable source of energy. The lowest figure is for demolition wood substituting oil in large combustion facilities, the highest for fuel wood used in dwellings to substitute electricity produced by coal-based power plants.Avoided GHG emissions per m³ wood used for energy were from 0.210 to 0.640 tonne CO₂-equivalents. Related to GWh energy produced, avoided GHG emissions were from 250 to 360 tonne CO₂-equivalents. Avoided GHG emissions per tonne CO₂ in the wood are 0.28–0.70 tonne CO₂-equivalents. The most important factors were technology used for combustion, which energy that is substituted, densities, and heating values. Inputs concerning harvest, transport, and production of the wood energy are not important.Overall, taking the uncertainties into account there is not much difference in avoided GHG emissions for the different kinds of wood energy.     

Life cycle GHG assessment of fossil fuel power plants with carbon capture and storage

The evaluation of life cycle greenhouse gas emissions from power generation with carbon capture and storage (CCS) is a critical factor in energy and policy analysis. The current paper examines life cycle emissions from three types of fossil-fuel-based power plants, namely supercritical pulverized coal (super-PC), natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC), with and without CCS. Results show that, for a 90% CO₂ capture efficiency, life cycle GHG emissions are reduced by 75–84% depending on what technology is used. With GHG emissions less than 170 g/kWh, IGCC technology is found to be favorable to NGCC with CCS. Sensitivity analysis reveals that, for coal power plants, varying the CO₂ capture efficiency and the coal transport distance has a more pronounced effect on life cycle GHG emissions than changing the length of CO₂ transport pipeline. Finally, it is concluded from the current study that while the global warming potential is reduced when MEA-based CO₂ capture is employed, the increase in other air pollutants such as NO_x and NH₃ leads to higher eutrophication and acidification potentials.     

Scenario analysis on CO2 emissions reduction potential in China's iron and steel industry

The international climate community has begun to assess a range of possible options for strengthening the international climate change effort after 2012. Analysis of the potential for sector-based emissions reduction and relevant mitigation options will provide the necessary background information for the debate. In order to assess the CO₂ abatement potential of China's steel industry, a model was developed using LEAP software to generate 3 different CO₂ emission scenarios for the industry from 2000 to 2030. The abatement potentials of different scenarios were compared, and their respective feasibilities were assessed according to the cost information. High priority abatement measures were then identified. The results show that the average CO₂ abatement per year in the Recent Policy scenario and in the New Policy scenario, compared with the reference scenario, are 51 and 107 million tons, respectively. The corresponding total incremental costs are 9.34 and 80.95 billion dollars. It is concluded that there is great potential for CO₂ abatement in China's steel industry. Adjusting the structure of the industry and technological advancement will play an important role in emissions reduction. Successful implementation of current sustainable development policies and measures will result in CO₂ abatement at a low cost. However, to achieve higher levels of abatement, the cost will increase dramatically. In the near future, specific energy conservation technologies such as dry coke quenching, exhaust gas and heat recovery equipment will be of great significance. However, taking a long term perspective, emissions reduction will rely more on the adjustment of production processes and the application of more modern large scale plants. Advanced blast furnace technology will inevitably play an important role.     

Plug-in hybrid electric vehicles—A low-carbon solution for Ireland?

Between 1990 and 2006, the primary energy requirement of the Irish transport sector increased by 166%. Associated greenhouse gas (GHG) emissions have followed a corresponding trajectory, and are responsible—at least in part—for Ireland’s probable failure to meet its Kyoto targets. As in most countries, Ireland’s transport sector is almost totally reliant on oil—a commodity for which Ireland is totally dependent on imports—and therefore vulnerable to supply and price shocks. Conversely, the efficiency and carbon intensity of the Irish electricity supply system have both improved dramatically over the same period, with significant further improvements projected over the coming decade. This paper analyses the prospects for leveraging these changes by increasing the electrification of the Irish transport sector. Specifically, the potential benefits of plug-in hybrid-electric vehicles (PHEV) are assessed, in terms of reducing primary energy requirement (PER) and CO₂ emissions. It is shown that, on a per-km basis, PHEV offer the potential for reductions of 50% or more in passenger car PER and CO₂ intensity. However, the time required to turn over the existing fleet means that a decade or more will be required to significantly impact PER and emissions of the PC fleet.     

Price determination of ETS allowances through the switching level of coal and gas in the power sector

This paper discusses the opportunities that exist for reducing greenhouse gases (GHG) emissions by switching from coal to gas‐fired units in electricity generation, ‘forced’ by the European Union Greenhouse Gas Emission Trading Scheme (EU ETS) price level of CO₂. It attempts to find efficient GHG cost profiles leading to a reasonable GHG emission reduction. In a methodological demonstration case (an electricity generation system consisting of two coal and two gas‐fired power plants), we demonstrate how a GHG emission cost can lead to a certain switch of power plants with an accompanying GHG emission reduction. This GHG emission cost is dependent on the load level. The switching point method is applied to an electricity generation system similar to the Belgian one. It is found that the greatest opportunities for GHG emission reductions are situated in the summer season. By switching only the coal‐fired units with the combined cycle (CC) gas‐fired units, a significant GHG emission reduction is possible at a modest cost. With the simulation tool E‐Simulate, the effect of a GHG emission cost in the summer season is investigated. A potential GHG emission reduction of 9.5% in relation to the case where there is no cost linked to GHG emission is possible at a relative low cost. When implementing a GHG cost in winter season, a smaller GHG reduction occurs while costs are higher. Copyright © 2006 John Wiley & Sons, Ltd.