Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

China’s aluminum (Al) production has released a huge amount of greenhouse gas (GHG) emissions. As one of the biggest country of primary Al production, China must mitigate its overall GHG emission from its Al industry so that the national carbon neutrality target can be achieved. Under such a background, the study described in this paper conducts a dynamic material flow analysis to reveal the spatiotemporal evolution features of Al flows in China from 2000 to 2020. Decomposition analysis is also performed to uncover the driving factors of GHG emission generated from the Al industry. The major findings include the fact that China’s primary Al production center has transferred to the western region; the primary Al smelting and carbon anode consumption are the most carbon-intensive processes in the Al life cycle; the accumulative GHG emission from electricity accounts for 78.14% of the total GHG emission generated from the Al industry; China’s current Al recycling ratio is low although the corresponding GHG emission can be reduced by 93.73% if all the primary Al can be replaced by secondary Al; and the total GHG emission can be reduced by 88.58% if major primary Al manufacturing firms are transferred from Inner Mongolia to Yunnan. Based upon these findings and considering regional disparity, several policy implications are proposed, including promotion of secondary Al production, support of clean electricity penetration, and relocation of the Al industry.     

Large-scale long-distance land-based hydrogen transportation systems: A comparative techno-economic and greenhouse gas emission assessment

Interest in hydrogen as an energy carrier is growing as countries look to reduce greenhouse gas (GHG) emissions in hard-to-abate sectors. Previous works have focused on hydrogen production, well-to-wheel analysis of fuel cell vehicles, and vehicle refuelling costs and emissions. These studies use high-level estimates for the hydrogen transportation systems that lack sufficient granularity for techno-economic and GHG emissions analysis. In this work, we assess and compare the unit costs and emission footprints (direct and indirect) of 32 systems for hydrogen transportation. Process-based models were used to examine the transportation of pure hydrogen (hydrogen pipeline and truck transport of gaseous and liquified hydrogen), hydrogen-natural gas blends (pipeline), ammonia (pipeline), and liquid organic hydrogen carriers (pipeline and rail). We used sensitivity and uncertainty analyses to determine the parameters impacting the cost and emission estimates. At 1000 km, the pure hydrogen pipelines have a levelized cost of $0.66/kg H₂ and a GHG footprint of 595 gCO₂eq/kg H₂. At 1000 km, ammonia, liquid organic hydrogen carrier, and truck transport scenarios are more than twice as expensive as pure hydrogen pipeline and hythane, and more than 1.5 times as expensive at 3000 km. The GHG emission footprints of pure hydrogen pipeline transport and ammonia transport are comparable, whereas all other transport systems are more than twice as high. These results may be informative for government agencies developing policies around clean hydrogen internationally.     

Design and implementation of carbon cap and dividend policies

An important concept in discussions of carbon management policies is cap and dividend, where some fraction of the revenues of an auction on emission allowances is returned to citizens on an equal per capita basis. This policy tool has some important features; it emphasizes the fact that the atmosphere is a common property resource, and it is a highly transparent measure that can be effectively used to protect the income of low-income individuals. In this paper we examine this policy in the California context, and focus on the costs and impacts of a cap and dividend scheme when applied to carbon emissions associated with electricity, natural gas and transportation services. We find that cap and dividend can effectively be used to address the economic impacts of carbon management policies, making them progressive for the lowest-income members of society. We find that the majority of households receive positive net benefits from the policy even with the government retaining half of the auction revenue. If auction revenues are instead dedicated only to low-income households, the majority of low-income households can be fully compensated even with the state government retaining upwards of 90% of auction revenues for other purposes.     

How a Pareto frontier complements scenario projections in land use change impact assessment

To evaluate the sustainability of potential agricultural land developments, scenario projections with land use change models are often combined with environmental impact assessments. Although this allows inter-scenario comparison of impacts, it does not permit interpretation of scenarios in the light of theoretically optimal impacts. A Pareto frontier provides this information. We demonstrate this for ethanol production in Goiás, Brazil, in 2030. For a Business-as-Usual scenario projection, the spatial configuration, production costs, and GHG emissions of the production chain are compared with those obtained from spatial optimization and summarized by the Pareto frontier. Projected production costs are 729 $/m³ ethanol, with GHG emissions of 40 kg CO₂-eq/m³ ethanol. The Pareto frontier indicates an improvement potential of ∼50 $/m³ ethanol when keeping emissions fixed, or ∼250 kg CO₂-eq/m³ ethanol when keeping costs fixed. Robust locations having low costs and emissions show where and how improvements are reached, offering instruments for policy (re)design.     

Potentials of GHG reductions from wastewater treatment for the CDM

The study aims to evaluate the potential of GHG (greenhouse gas) reductions by installing an anaerobic digester in a wastewater treatment facility in Southeast Asia. Then the break-even point of additional investment to reduce GHG is obtained by exchanging carbon price as emissions credits. In the project scenario, the wastewater treatment system has the digester, where methane (biogas) is produced and recovered. Compared with the baseline scenario, the biogas has calorific value to produce heat and electri...     

Comparative assessment of future motor vehicles under various climate change mitigation scenarios

The aim of comparative assessment of future road transport technologies is to find the cheapest motor vehicles in terms of private and external Greenhouse Gas (GHG) emission costs under various international climate change mitigation scenarios in 2020 and 2050. The comparative assessment of the main road transport technologies ranging from conventional vehicles to hybrid electric vehicles was performed. The main indicators for comparative future motor vehicles assessment are: private costs and life cycle external costs of GHG emissions. The obtained ranking of road transport technologies allows to identify the most perspective future motor vehicles taking into account international climate change mitigation constraints and to promote these road technologies by policy tools. The cheapest road transport technologies in 2020 and 2050 are: the main results presented in this paper were obtained during EU financed Framework 7 project “PLANETS” dealing with probabilistic long-term assessment of new energy technology scenarios.     

Carbon capture: Energy wasting technologies or the MCFCs challenge?

Carbon dioxide is more and more pointed out as one of the factors mostly responsible of climate changes. As a consequence the reduction of CO₂ emissions, especially in the energy generation field, is becoming a worldwide must.This paper presents an overview on the main issues that are expected to affect, from this standpoint, power generation scenario and a spur for a critical comparison among ways to capture CO₂ by proposing new aspects to be considered within the evaluation criteria.In particular attention is drawn on the fully innovative opportunities that are offered by Molten Carbonate Fuel Cells (MCFCs) as a unique option suitable to effectively combine carbon capture from thermal plants and typical benefits of hydrogen and fuel cell power generation.As an example, such a new option is compared with one of the most common technologies forecast for reducing carbon dioxide emissions and relevant results are shortly presented.     

Policy progress in mitigation of climate change in Taiwan

To make an active contribution to the global effort in mitigation of climate change, Taiwan government has implemented the “Frameworks for Sustainable Energy Policy—An Energy-Saving and Carbon-Reduction Action Plan” in June 2008. It has made a commitment of a stepwise reduction of nationwide greenhouse gas (GHG) emissions, which returns the nationwide GHG emission to 2008 levels by 2020, then reduces to 2000 levels by 2025, and finally cuts 50% of 2000 levels by 2050. The fundamental strategy is to reduce the GHG emission under acceptable economic development and energy security to achieve generation-spanning triple-win in energy, environment and economy. The major policy instruments such as “Statute for Renewable Energy Development”, “GHG Reduction Law (draft),” “Regulation for Energy Tax (draft),” and “Energy Management Act” have been either implemented or scheduled for legislative reviewing. The purpose of this paper is to present an updated review of the outcomes of GHG emission reduction in Taiwan. In addition, the progress and priority of policy instruments in GHG emission reduction are analyzed as well.     

Energy savings certificates: A market-based tool for reducing greenhouse gas emissions

Energy savings certificates (ESCs) are potentially a major tool that can be used by regulators and policy makers in reducing greenhouse gas (GHG) emissions. In this paper, we present our findings on the experience to date with ESCs, outline potential program opportunities in the US, and conclude with our perspective on how to proceed with the use of ESCs, particularly as a component of GHG reduction programs.     

Does battery storage lead to lower GHG emissions?

A study of the Australian National Electricity Market shows that using battery storage in the Australian national electricity grid reduces CO₂ emissions by providing further flexibility for the operation of conventional generators and also by decreasing the amount of unused renewable energy. Interestingly, energy storage is more efficient at reducing carbon emissions in the context of higher carbon and/or fuel prices. In addition to reducing emissions, battery storage can decrease the cost of delivered energy.