[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Mercedes-Benz B-Class Electric Drive reduces lifecycle CO2 emissions by as much as 64% compared to B 180 gasoline model
December 17, 2014
|CO2 emissions of the B-Class Electric Drive compared with the B 180 gasoline-engine variant [t/car]. Click to enlarge.|
The Mercedes-Benz B-Class Electric Drive (earlier post) delivers up to 64% lower CO2 emissions than the equivalent B 180 gasoline model (when charged with hydroelectricity), according to Mercedes-Benz and TÜV Süd. The 132 kW B Class Electric Drive has a range of some 200 km (124 miles). TÜV Süd has awarded the electric-drive Sports Tourer the environmental certificate in accordance with ISO standard TR 14062 based on a comprehensive life-cycle assessment of the B-Class Electric Drive.
Over its entire life cycle, comprising production, use over 160,000 kilometers (99,419 miles) and recycling, the B-Class Electric Drive produces emissions of CO2 that are 24% (7.2 tonnes – EU electricity mix) or 64% (19 tonnes – hydroelectricity) lower than those of the B 180, despite the higher emissions generated during the production process.
Lifecycle analysis of Amyris renewable jet from sugar cane finds “substantial potential” to mitigate GHG emissions, but a wide range of potential outcomes
November 25, 2014
|Monte Carlo results for the net life cycle emissions of the renewable jet fuel from sugar cane. Credit: ACS, Moreira et al.. Click to enlarge.|
Brazilian researchers evaluating the lifecycle GHG emissions of a renewable jet fuel produced from sugar cane in Brazil using Amyris’ proprietary technology platform (earlier post) found that the farnesane-based renewable fuel presents “a substantial potential” to mitigate the GHG emissions of the aviation sector. Their paper is published in the ACS journal Environmental Science & Technology.
In their base case, the researchers calculated a “rather optimistic” GHG footprint of 8.5g CO2eq/MJ; lifecycle emissions of fossil jet fuel usually lie within the 80−95g CO2eq/MJ range. However, they noted, the estimation is highly uncertain, with a number of factors—especially related to electricity exports, sugar cane farming itself, and agrochemicals production and use—significantly affect the outcome. The results of the Monte Carlo analysis indicate life cycle emissions of 21 ± 11 g CO2eq/MJ (mean ± SD), with substantial influence from the LUC factor.
Ecofys report concludes current European regulations underestimating GHG reductions
November 13, 2014
Substituting biofuels for marginal fossil-based liquid fuels results in the avoidance of significant GHG emissions that are not currently accounted for in the European Renewable Energy Directive (2009/28/EC), according to a new analysis by the consultancy Ecofys. The study was commissioned by the European Oilseed Alliance (EOA), the European Biodiesel Board (EBB) and the European Vegetable Oil and Proteinmeal Industry (FEDIOL).
The European RED and the Fuel Quality Directive (2009/30/EC) both assess the GHG benefits of biofuels by comparing the lifecycle emissions of biofuels to a “fossil comparator”. However, the Ecofys authors note, the current comparator does not reflect the increasing emissions of fossil fuels that are becoming more difficult to extract. In addition, they argue, biofuels should not just be compared to the average performance of gasoline or diesel but with the fossil fuels they most likely replace—i.e. those that are marginally “not produced”.
Study casting doubt on GHG benefits of corn stover ethanol draws sharp criticism by other researchers; Liska responds
October 30, 2014
A study published earlier this year in the journal Nature Climate Change that cast doubt on whether biofuels produced from corn residue could meet federal mandates for cellulosic biofuels to reduce greenhouse gas emissions by 60% compared to gasoline (earlier post) has drawn critical response published as correspondence in the same journal.
The study led by University of Nebraska-Lincoln assistant professor Adam Liska, funded through a three-year, $500,000-grant from the US Department of Energy, used carbon dioxide measurements taken from 2001 to 2010 to validate a soil carbon model that was built using data from 36 field studies across North America. Among their findings were that using corn crop residue to make ethanol and other biofuels reduces soil carbon and under some conditions can generate more greenhouse gases than gasoline.
Argonne releases GREET 2014 lifecycle analysis software; unified graphical toolbox and database
October 08, 2014
The GREET (The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model) team at Argonne National Laboratory has released a new version of the widely used GREET lifecycle analysis tool, GREET 2014. GREET 2014 provides a fully graphical toolbox with which users can perform life cycle analysis simulations of alternative transportation fuels and vehicle technologies with just a few clicks.
GREET originally began development as an Excel spreadsheet back in 1996. As the detail and complexity of the tool has grown, the spreadsheet-based approach became unwieldy, the team said. As a result, the GREET team is now using the new software (called GREET.NET to differentiate from GREET Excel) as a new platform for life cycle assessment studies and database management. The new platform combines all the previous Excel spreadsheets in a single environment with a single database that is now easier to maintain and manage.
ORNL study finds best current use of natural gas for cars is efficient production of electricity for EVs
September 24, 2014
|Top: Components of well-to-wheels pathway. Middle: WTW efficiency for CNGVs. Bottom: WTW efficiency for EVs. Curran et al. Click to enlarge.|
A well-to-wheels analysis of the use of natural gas for passenger vehicles by a team of researchers from Oak Ridge National Laboratory (ORNL) has found that, with a high PTW (pump-to-wheels) efficiency and the potential for high electrical generation efficiency with NGCC (natural gas combined cycle) turbines, natural gas currently is best used in an efficient stationary power application for charging EVs.
However, they also noted, high PTW efficiencies and the moderate fuel economies of current compressed natural gas vehicles (CNGVs) make them a viable option as well. If CNG were to be eventually used in hybrids, the advantage of the electric generation/EV option shrinks. Their open access paper is published in the journal Energy.
US MARAD study finds marine use of natural gas substantially reduces some air pollutants and slightly reduces GHG emissions
August 26, 2014
A recently released total fuel cycle analysis for maritime case studies shows that natural gas fuels reduce some air quality pollutants substantially, and reduce major greenhouse gas (GHG) emissions slightly, when compared to conventional petroleum-based marine fuels (low-sulfur and high-sulfur). The study was released by the US Department of Transportation’s (DOT) Maritime Administration (MARAD) and was conducted through a cooperative partnership with the Maritime Administration, the University of Delaware and The Rochester Institute of Technology.
They also found that the upstream configuration for natural gas supply matters in terms of minimizing GHG emissions on a total fuel cycle basis, and that the current infrastructure for marine fuels may produce fewer GHGs. Continued improvements to minimize downstream emissions of methane during vessel-engine operations will also contribute to lower GHG emissions from marine applications of natural gas fuels.
U. Mich study: natural-gas-based ICE, BEV and FCV all show promise for environmental benefits relative to conventional ICE
August 19, 2014
Results of a lifecycle analysis by a team at the University of Michigan suggest that multiple types of natural gas-powered vehicles—i.e., natural-gas burning ICE vehicles; battery-electric vehicles (BEVs) recharged with gas-generated electricity; and fuel cell vehicles (FCVs) using hydrogen produced from natural gas—all show promise for reducing environmental impacts, energy demand and climate change impacts relative to conventional petroleum-fueled internal combustion engined vehicles for personal mobility.
Qiang Dai and Christian Lastoskie found that BEVs and FCVs in particular offer significant reductions in greenhouse gas emissions, especially if carbon capture and sequestration (CCS) technologies are implemented at the fuel conversion facilities. Their study appears in the ACS journal Energy & Fuels.
3rd generation Audi TT reduces full lifecycle GHGs by 11% compared to predecessor
August 18, 2014
|Lifecycle greenhouse gas emissions for 2nd and 3rd generation TTs. Click to enlarge.|
Audi’s new third-generation TT reduces life-cycle greenhouse gas emissions by 11% compared to its predecessor. This results in a reduction of around 5.5 tonnes of GHGs—CO2, methane, nitrous oxide and halogenated organic emissions—over its entire lifecycle. At the same time, Audi has increased the power output in the new TT by up to 14%.
A number of technologies have contributed towards the positive life cycle assessment of the Audi TT, including lightweight construction. Using an intelligent combination of materials, Audi engineers have, for the second time in a row, succeeded in reducing the car’s unladen weight.
U Mich professor finds fuel cycle analysis for evaluating CO2 impacts of liquid fuels is fatally flawed; calls for focus on CO2 removal
July 28, 2014
Fuel cycle analysis (FCA)—or “well-to-wheels analysis”—is a type of lifecycle analysis (LCA) that examines fuel products and their supply chains, and that has greatly influenced climate-related research priorities and public policies for transportation fuels.
However, in a major review of methods for evaluating the net CO2 impacts of liquid transportation fuels, Professor John DeCicco at the University of Michigan Energy Institute (UMEI) compared FCA to other methods of analysis, and found “flaws fatal enough to raise serious concerns about the role of FCA in shaping fuel-related CO2 mitigation strategies. Instead, DeCicco proposes “setting the lifecycle paradigm aside” and focusing on the problem of carbon dioxide removal.
Researchers propose CO2 recycling to improve Fischer-Tropsch GTL efficiency and reduce total CO2 emissions
June 21, 2014
|Overview of the CUGP processes. Credit: ACS, Zhang et al. Click to enlarge.|
Researchers in South Korea are suggesting two new carbon-dioxide-utilized Gas-to-Liquids processes (CUGP) to increase the overall efficiency of conventional Fischer-Tropsch GTL. In a paper in the ACS journal Environmental Science & Technology, they report that the two CUGP options increase carbon efficiency by 21.1−41.3% and thermal efficiency by 15.7−40.7%, with total CO2 emissions reduced by 82.0−88.4%, compared to different conventional F-T processes.
This results in a decrease in total CO2 emissions to less than 5g CO2/MJ F-T product, compared to a range of 27.0 to 36.2g CO2/MJ F-T product for the conventional processes.
MIT study finds significant economic and environmental benefits from designing US LDVs to use higher octane gasoline (98 RON)
May 29, 2014
In a companion study to an SAE paper presented in April (earlier post), researchers at MIT have quantified the net economic and CO2 emissions benefit that could be obtained by utilizing 98 RON gasoline in light-duty vehicles, based on reasonable assumptions for possible refinery changes and the evolution of the LDV fleet. The paper, they note, is the first modern, peer-reviewed publication to address the costs and benefits of introducing higher octane gasoline.
According to the analysis, published in the ACS journal Environmental Science & Technology, greater use of 98 RON gasoline in appropriately tuned vehicles could further reduce annual gasoline consumption in the US by 3.0–4.4%. Even accounting for the increase in refinery emissions from production of additional high-RON gasoline, net CO2 emissions are reduced by 19–35 Mt/y in 2040 (2.5–4.7% of total direct LDV CO2 emissions). The MIT team estimated the annual direct economic benefit to be $0.4–6.4 billion in 2040, and the annual net societal benefit—including the social cost of carbon—to be $1.7–8.8 billion in 2040.
Study finds removing corn residue for biofuel production can decrease soil organic carbon and increase CO2 emissions; may miss mandated 60% GHG reduction
April 21, 2014
|Contribution of modeled CO2 emissions from SOC to the life cycle of biofuel from corn residue. Error bars are ± one standard deviation. Liska et al. Click to enlarge.|
Using corn crop residue to make ethanol and other biofuels reduces soil carbon and under some conditions can generate more greenhouse gases than gasoline, according to a major, multi-year study by a University of Nebraska-Lincoln team of researchers published in the journal Nature Climate Change. The findings cast doubt on whether biofuels produced from corn residue can be used to meet federal mandates for cellulosic biofuels to reduce greenhouse gas emissions 60% compared to gasoline.
The study, led by assistant professor Adam Liska, was funded through a three-year, $500,000-grant from the US Department of Energy, and used carbon dioxide measurements taken from 2001 to 2010 to validate a soil carbon model that was built using data from 36 field studies across North America, Europe, Africa and Asia. Using USDA soil maps and crop yields, they extrapolated potential carbon dioxide emissions across 580 million 30-meter by 30-meter geospatial cells in Corn Belt states.
ERTRAC publishes roadmap on energy carriers and powertrains; role for power-to-gas
April 07, 2014
|Main technology trends and the vision share of engines in Europe. [ERTRAC / EUCAR] Click to enlarge.|
The European Road Transport Research Advisory Council (ERTRAC) has published a new roadmap assessing energy carriers and powertrains in the context of the European target to achieve a 60% reduction in CO2 emissions from transport by 2050. ERTRAC is the European Technology Platform (ETP) for Road Transport recognized and supported by the European Commission. ERTRAC has more than 50 members, representing all the actors of the Road Transport System: transport industry, European associations, EU Member States, local authorities, European Commission services, etc.
The analysis concludes that while the goal is challenging, it is also realizable; however the overall high-level goals need to be segmented into precise targets for the different industries and stakeholders. For the topic of future road mobility these are the development of alternative and decarbonized fuels and energy carriers; and higher powertrain efficiency leading to cleaner mobility and reduction in resource demand.
Full lifecycle CO2 of new Mercedes C-Class 10% less than outgoing model
March 31, 2014
|CO2 emissions of the C 180 in comparison to its predecessor [t/car]. Source: Mercedes-Benz. Click to enlarge.|
Over the course of its entire life cycle—from its manufacture through 200,000 kilometer of driving to its recycling—the new Mercedes-Benz C-Class (earlier post) produces around 10% fewer CO2 emissions than its predecessor at the time of its market exit (compared to the time of its launch in 2007 the improvement is much higher, at around 28%). The C 180 (115 kW) with manual transmission was taken as the base variant of the new C-Class at market launch for the lifecycle analysis; it was compared with the corresponding preceding model. The analysis was validated by TÜV SÜD Management Service GmbH.
Over the entire lifecycle of the C 180, the lifecycle analysis yields a primary energy consumption of 521 gigajoules (corresponding to the energy content of around 16,000 liters of gasoline); an environmental input of approx. 35 tonnes of CO2; around 19 kilograms of non-methane volatile organic compounds (NMVOC); around 25 kilograms of nitrogen oxides (NOx); and 37 kilograms of sulfur dioxide (SO2). For CO2 emissions—and likewise for primary energy consumption—the use phase dominates with a share of 78 and 74% respectively.
JEC updates well-to-wheels study on automotive fuels and powertrains; electro-mobility, natural gas and biofuels
March 27, 2014
|WTW energy expended and GHG emissions for conventional fuels ICE and hybrid vehicles shows the potential for improvement of conventional fuels and ICE based vehicles. Source: EUR 26236 EN - 2014 Click to enlarge.|
Europe’s Joint Research Centre (JRC) and its partners in the JEC Consortium—JRC, EUCAR (the European Council for Automotive R&D) and CONCAWE (the oil companies European association for environment, health and safety in refining and distribution)—have published a new version of the Well-to-Wheels Analysis of Future Automotive Fuels and Powertrains in the European Context. (Earlier post.)
The updated version includes a longer-term outlook by expanding the time horizon from 2010 and beyond to 2020 and beyond. It adds an assessment of electrically chargeable vehicle configurations, such as plug-in hybrid, range extended, battery and fuel-cell electric vehicles. It also introduces an update of natural gas pathways, taking into account the addition of a European shale gas pathway. Furthermore, biofuel pathways, including an entirely new approach to NOx emissions from farming, were thoroughly revised.
Lifecycle study explores production of NdFeB rare-earth magnets from primary production and recycling pathways
March 19, 2014
A lifecycle study comparing the virgin production route of neodymium−iron−boron (NdFeB) magnets with two hypothetical recycling processes found that recycling of neodymium, especially via manual dismantling, is preferable to primary production, with some environmental indicators showing an order of magnitude improvement.
The choice of recycling technology is also important with respect to resource recovery, the study by a team from the Netherland and the UK found. While manual disassembly allows in principle for all magnetic material to be recovered, shredding leads to very low recovery rates (<10%). The study appears in the ACS journal Environmental Science & Technology.
Lifecycle study finds that environmental impacts of silicon-anode Li-ion battery could be roughly comparable with conventional Li-ion battery
February 17, 2014
|Life cycle impact benchmarking between LIB packs with SiNW and graphite anode. Units of the X-axis values are different and shown under each impact category name on Y-axis. Credit: ACS, Li et al. Click to enlarge.|
A lifecycle assessment (LCA) of silicon nanowire (SiNW) anodes for Li-ion batteries (LIBs) by researchers at the University of Wisconsin-Milwaukee has concluded that a LIB pack using SiNW anodes from metal-assisted chemical etching could have environmental impacts comparable with those of a conventional Li-ion battery pack, while significantly increasing the battery energy storage. The study is published in the ACS journal Environmental Science & Technology.
The LCA was based on the average US driving and electricity supply conditions. The researchers characterized nanowastes and nanoparticle emissions from the SiNW synthesis. The results showed that more than 50% of most characterized impacts are generated from the battery operations, while the battery anode with SiNW material contributes to around 15% of global warming potential and 10% of human toxicity potential.
Study concludes that NG leakage higher than reflected in inventories; transportation fuel climate benefits questioned
February 14, 2014
A review of 20 years of technical literature on natural gas (NG) emissions in the United States and Canada comprising more than 200 papers has concluded that official inventories consistently underestimate actual CH4 emissions due to leakage from the natural gas system. “Atmospheric tests covering the entire country indicate emissions around 50 percent more than EPA estimates,” said lead author Adam Brandt at Stanford University. The study, which is authored by researchers from seven universities, several national laboratories and federal government bodies and other organizations, is published in the journal Science.
Among the other high-level findings of the review are that (i) the natural gas and oil sectors are important contributors to the leakage; (ii) many independent experiments suggest that a small number of “superemitters” could be responsible for a large fraction of leakage; (iii) recent regional atmospheric studies with very high emissions rates are unlikely to be representative of typical natural gas system leakage rates; and (iv) assessments using 100-year impact indicators show system-wide leakage is unlikely to be large enough to negate climate benefits of coal-to-NG substitution.
State Department releases Keystone XL Final Supplemental Environmental Impact Statement
February 01, 2014
|Incremental well-to-wheels GHG emissions from WCSB Oil Sands Crudes Compared to Well-to-Wheels GHG Emissions from Displacing Reference Crudes Click to enlarge.|
The State Department released the long-anticipated and voluminous Final Supplemental Environmental Impact Statement (Final Supplemental EIS) for the proposed Keystone XL oil pipeline project. The document is posted on State’s Keystone project site, which it has run since the beginning of the Keystone XL Presidential permit process in 2008.
The analysis in the Final Supplemental EIS builds on the Draft Supplemental Environmental Impact Statement released on 1 March 2013 (earlier post) as well as the documents released in 2011 as part of the previous Keystone XL Pipeline application. Notable changes since the prior Draft Supplemental Environmental Impact Statement include an expanded analysis of potential oil releases; an expanded climate change analysis; an updated oil market analysis incorporating new economic modeling; and an expanded analysis of rail transport.
LCA study finds carbon intensity of corn ethanol decreasing, gasoline rising; ethanol estimated 43-60% lower than oil by 2022
January 30, 2014
|Top: Weighted CI (g CO2 e/MJ) of petroleum fuels and corn ethanol consumed in the US over time. Bottom: Weighted CI of petroleum fuels consumed in the US and California over time. Click to enlarge.|
The carbon intensity (CI) of corn ethanol—i.e., the greenhouse gas emissions produced via the production of a volume of the fuel—is declining, while the average CI of gasoline produced from petroleum sources is gradually increasing, according to a recent report prepared by Life Cycle Associates, LLC for the Renewable Fuels Association (RFA). Life Cycle Associates has completed numerous life cycle analysis studies, including those to establish fuel pathway carbon intensities (CI) for the California Low Carbon Fuel Standard (LCFS).
According to the study, the average corn ethanol reduced GHG emissions by 32% compared to average petroleum gasoline in 2012—including prospective emissions from indirect land use change (ILUC) for corn ethanol. When compared to fuel produced from unconventional petroleum sources such tight oil from fracking and oil sands, average corn ethanol reduces GHG emissions by 37% compared to the former and 40% to the latter.
Swiss WTW study finds important role for alternative fuels as well as alt drivetrains in move to low-emissions vehicles
January 03, 2014
|WTW energy demand and GHG emissions for EV and PHEV drivetrains for various electricity sources; gasoline ICE vehicle is solid square, hybrid the hollow square. Click to enlarge.|
A comprehensive analysis of well-to-wheel (WTW) primary energy demand and greenhouse gas (GHG) emissions for the operation of conventional and alternative passenger vehicle drivetrains in Switzerland has concluded that alternative combustion fuels—not only alternative drivetrains such as PEVs or FCVs—play an important role in the transition towards low-emission vehicles.
The study by a team at the Swiss Federal Institute of Technology Zurich, reported in the Journal of Power Sources, is novel in three respects, the researchers said. First, it considers the performance of both mature and novel hydrogen production processes, multiple electricity generation pathways and several alternative drivetrains. Second, it is specific to Switzerland. Third, the analysis offers a novel comparison of drivetrain and energy carrier production pathways based on natural resource categories.