[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.]
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.
BAL scientists engineer yeast to produce ethanol from brown seaweed; brown seaweed biorefinery
December 03, 2013
An international team of researchers from Bio Architecture Labs, a synthetic biology and enzyme design company focused on the production of biofuels and biochemicals from macroalgae (seaweed) (earlier post), reports the development of a synthetic yeast platform based on Saccharomyces cerevisiae that can efficiently produce ethanol from brown seaweed; the paper is published in the journal Nature.
In January 2012, BAL scientists reported the engineering a strain of Eschericia coli that could break down and then ferment alginate—one of the most abundant sugars in brown algae, but a sugar that industrial microbes can’t metabolize—into ethanol. That paper was featured on the cover of the journal Science. (Earlier post.)
Ford researchers present physics-based model of mass-induced fuel consumption for better insight into lightweighting benefits
November 25, 2013
A pair of researchers from Ford Motor Company’s Systems Analytics and Environmental Sciences Department in Dearborn have developed a novel physics-based model of mass-induced fuel (MIF) consumption which can be used in vehicle life cycle assessments to provide better insight—i.e., from a more firm scientific foundation—on the potential benefits of lightweighting.
To illustrate the method, they used their model to estimate the MIF values for 2013 model year internal combustion engined using the US Environmental Protection Agency’s (EPA’s) fuel economy certification data. They found MIF values in the range of 0.2−0.5 L/(100 km 100 kg). As described in a paper on their work in the ACS journal Environmental Science & Technology, the results showed that lightweighting has the most benefit when applied to vehicles with high fuel consumption and high power.
Average carbon intensity of oil sands production has dropped ~36% in last 40 years; still 12-24% higher than conventional oil CI
November 21, 2013
|Trends in well-to-wheel pathway-specific CI. In situ production began in 1974, so no value is computable for 1970. Click to enlarge.|
The carbon intensity (CI) of Alberta oil sands production has significantly decreased over the last 40 years, according to a new study by a team from Stanford University published as an open access paper in the journal Environmental Research Letters.
Relying entirely on public and peer-reviewed data sources for the period from 1970 to 2010 (inclusive), the team found that industry-average full-fuel cycle (well-to-wheels, WTW) CI declined about 36% from 165 gCO2e MJ-1 higher heating value (HHV) of reformulated gasoline (RFG) to 105 (-12, +9) gCO2e MJ-1 HHV RFG. 2010 averages by production pathways are 102 gCO2e MJ-1 for mining and 111 gCO2e MJ-1 for in situ production.
TÜV SÜD Technical Inspectorate confirms BMW i3 can emit 30-50% less total life cycle greenhouse gases than comparable conventional vehicles
November 13, 2013
The BMW i3 battery electric vehicle can emit 30-50% less total life cycle greenhouse gases than comparable conventional vehicles depending upon the source of its electricity, according to its ISO 14040/14044 certificate from the TÜV SÜD Technical Inspectorate. (Earlier post.) Market launch for the i3 is on 16 November.
The 30% reduction is achieved by using energy from the EU 25 electricity mix, which takes account of all electricity generation in the European Union. The 50% reduction compared with conventional automobiles results as soon as the BMW i3 is powered exclusively by energy generated from renewables such as wind or solar power. ISO 14040/14004 are international standards for lifecycle assessment.
Georgia Tech study finds MD electric urban delivery trucks have cost advantages over diesel in some conditions; relative benefits depend on numerous factors
September 26, 2013
Researchers at Georgia Tech have compared medium-duty (MD) electric and diesel urban delivery trucks in terms of life-cycle energy consumption, greenhouse gas (GHG) emissions, and total cost of ownership (TCO). One surprise among their findings was that the electric truck had cost advantages over the diesel vehicle under some conditions. The team had expected that electric truck costs would always be higher, especially since the purchase price of the electric truck studied was higher than that of the diesel truck.
In a paper published in the ACS journal Environmental Science & Technology, they report that the relative benefits of electric trucks depend heavily on vehicle efficiency associated with drive cycle; diesel fuel price; travel demand; electric drive battery replacement and price; electricity generation and transmission efficiency; electric truck recharging infrastructure; and purchase price.
U-Mich researcher’s first-principles analysis challenges conventional carbon accounting for biofuels; implications for climate policy
September 24, 2013
In a paper that could have a significant impact on climate policies for transportation fuels, Dr. John M. DeCicco of the Energy Institute at the University of Michigan, Ann Arbor presents a rigorous first-principles analysis that undermines the common “biofuels recycle carbon” argument.
Published in the journal Climactic Change, the open access paper shows that while the carbon mitigation challenge for liquid fuels has been seen—incorrectly—as a fuel synthesis and substitution problem, it is in reality a net carbon uptake problem. Accordingly, DeCicco concludes, strategies should move away from a downstream focus on replacing fuel products to an upstream focus on achieving additional CO2 uptake through the most cost-effective and least damaging means possible. “All parties with an interest in the issue are advised to rethink their priorities accordingly,” he finishes.
Study finds HTL algal biofuels offer 50-70% lifecycle CO2 reduction compared to petroleum fuels; EROI and GHG comparable to or better than other biofuels
September 20, 2013
A new life cycle analysis by a team led by researchers at the University of Virginia has concluded that biofuel produced from algae via hydrothermal liquefaction (HTL) can reduce life cycle CO2 emissions by 50 to 70% compared to petroleum fuels, and also has energy burdens and GHG (greenhouse gas) emission profiles that are comparable to or better than conventional biofuels, cellulosic ethanol and soybean biodiesel.
HTL algae-derived gasoline has a considerably lower GHG footprint and a better EROI relative to conventional ethanol made from corn on a per MJ basis, the team found. The data suggest that a shift to algae-derived gasoline could have immediate climate benefits even using existing technologies, the authors noted. In addition, given expected technological improvements, the benefits of algae-derived gasoline will likely improve.
European Parliament backs 6% cap on land-based biofuels, switchover to advanced biofuels; no mandate
September 11, 2013
In a vote on draft legislation, the European Parliament has backed a cap on the use of biofuels produced from starch-rich crops, sugars, oil and other crops grown on land and a speedy switchover to new biofuels from alternative sources such as seaweed and waste. The measures aim to reduce greenhouse gas emissions that result from the turnover of agricultural land to biofuel production.
According to current legislation, member states must ensure that renewable energy accounts for at least 10% of energy consumption in transport by 2020. In the adopted text, MEPs (Members of the European Parliament) say land-based biofuels should not exceed 6% of the final energy consumption in transport by 2020. (The proposal by the European Commission on which the draft legislation was based had suggested an even lower 5% cap.)
Georgia Tech study suggests unlinking EVs from CAFE and coordinating with power sector for low-cost benefits
September 08, 2013
A team from Georgia Tech suggests, based on their modeling of electric vehicle (EV) adoption scenarios in each of six regions of the Eastern Interconnection (containing 70% of the US population), that coordinating EV adoption with the adoption of controlled EV charging, unlinking EVs from consideration in the CAFE fuel economy regulations; and implementing renewable electricity standards would deliver low-cost reductions in emissions and gasoline usage. (For the study, they define EVs as including both battery-electric (BEV) and plug-in hybrid electric (PHEV) vehicles.
Only in the case of high EV market share and a high renewable electricity standard (RES) do EVs make a material contribution to greenhouse gas (GHG) reductions, they found. However, managed EV adoption can reduce the cost of achieving GHG reductions through a RES, they concluded in their paper published in the ACS journal Environmental Science & Technology.
EPA grants Aemetis’ sorghum ethanol and biogas the D5 advanced biofuel RIN category
September 03, 2013
The US Environmental Protection Agency (EPA) has granted Aemetis, an advanced fuels and renewable chemicals company formerly known as AE Biofuels, approval to produce ethanol using grain sorghum and biogas at its converted corn ethanol plant to generate D5 Advanced Biofuels Renewable Identification Numbers (RINs).
Until now, the D5 Advanced Biofuels RIN portion of the RFS (Renewable Fuel Standard) has been mostly met by imported Brazilian sugarcane ethanol or by substituting D4 biodiesel RINs due to a lack of advanced ethanol production.
IHS-CERA concludes “no material impact” on US GHG from Keystone XL; heavy crude from Venezuela most likely replacement
August 09, 2013
The proposed Keystone XL pipeline for transporting oilsands-derived crude to Gulf Coast refineries would have “no material impact” on US greenhouse gas (GHG) emissions, according to a new Insight report by IHS CERA. In a June speech at Georgetown University, President Barack Obama said that the controversial Keystone XL pipeline would only be built if the project “does not significantly exacerbate the problem of carbon pollution.” (Earlier post.)
In the absence of the pipeline, alternate transportation routes would result in oilsands production growth being more or less unchanged, IHS CERA found. The study also found that any absence of oil sands on the US Gulf Coast would most likely be replaced by imports of heavy crude oil from Venezuela, which has the same carbon footprint as oilsands crude.
Lifecycle analysis of energy use and pollution from gasoline, CNG and electric vehicles in 6 southwestern states highlights variability of benefits
July 29, 2013
|Comparison of greenhouse gas emissions from new vehicles in 2020, EVs by state power mix. Percentages are relative to gasoline baseline. Click to enlarge.|
A report for policymakers issued by the Southwest Energy Efficiency Project (SWEEP) has found that in Arizona, Colorado and Nevada, electric vehicles offer the cleanest ride, while in New Mexico, Utah, and Wyoming that’s not necessarily the case. SWEEP promotes greater energy efficiency in a six-state region that includes Arizona, Colorado, Nevada, New Mexico, Utah, and Wyoming.
The report, “Transportation Fuels for the Southwest”, compared the well-to-wheels energy use and air pollution emitted by vehicles fueled by gasoline, compressed natural gas and electricity in order to determine which fuel is cleanest in each of the six southwestern states.
GM to double models with 40 mpg highway or better by 2017; ongoing manufacturing efficiency improvements
July 12, 2013
Describing its product goals and tracking progress toward its 2020 manufacturing priorities in its 2012 Sustainability Report, General Motors reaffirmed its commitment to further reduce the energy used and the environmental impacts of building and operating an automobile.
GM has made three product commitments for 2017 related to its sustainability strategy: to have 500,000 vehicles on the road in the US with some form of electrification (earlier post); to double the number of US models that can achieve an EPA-estimated 40 mpg US (5.9 l/100 km) highway or better; and to reduce the average CO2 tailpipe emissions of its US fleet by 15%. Opel also estimates it will reduce the average carbon tailpipe emissions from its fleet by 27% by 2020.
New LowCVP report highlights need to go “beyond the tailpipe” for CO2 metrics for vehicles
July 11, 2013
|Proportion of lifecycle CO2e emissions for future cars 2020-2030. The new study projects the increasing dominance of the production phase in terms of lifecycle CO2 impacts. Click to enlarge.|
The introduction of new energy technologies in road transport will mean that the current tailpipe measures of the climate impact of vehicles will become increasingly inadequate in future.
A new report—“Life Cycle CO2e Assessment of Low Carbon Cars 2020-2030”—prepared for the UK’s LowCVP Low Carbon Vehicle Partnership by PE International and validated by Partnership stakeholders—shows how total life cycle CO2e emissions will change for different vehicle technologies in the future and estimates how the balance of emissions will alter for different stages in the life cycle for the varying technologies.
Renault makes public its lifecycle study of Fluence ICE vs Fluence EV
|Renault’s comparison of the carbon footprint of EV and ICE vehicles over production, operation and end of life. The EV footprint (Fluence Z.E.) is shown with both UK and French grid mixes. Click to enlarge.|
Renault recently made public the findings of an internal study, published first in October 2011, detailing and comparing the lifecycle assessments (LCAs) of the battery-electric and two internal combustion engined versions (gasoline and diesel) of the Renault Fluence. The study used the series production versions launched in 2011, with the assumption of operation for 150,000 km (93,205 miles). (Since the BEV version has a shorter range, Renault noted, the way in which the miles are accumulated could differ from that of the ICE vehicles.)
The publication gives the opportunity for an “apples-to-apples” comparison between the environmental impacts of the two types of powertrains: same manufacturer, same model, same boundary conditions. Nevertheless, Renault noted, the study is contrasting a new technology (EVs) with a well-developed one; “environmental progresses are expected in a short term thank to key process improvement and massification of the production.”
Georgia Tech life-cycle study finds TCO of medium-duty electric and diesel delivery trucks similar; electric life-cycle energy use and GHG lower than diesel
July 06, 2013
|Life-cycle energy use and GHG emissions normalized with NYCC diesel case (8.06 MJ/t·km and 0.63 kgCO2e/t·km) at 100%. Numbers in red are net total including recycling effect. Credit: ACS, Lee et al. Click to enlarge.|
Comparing life-cycle energy consumption, greenhouse gas (GHG) emissions, and total cost of ownership (TCO) of medium-duty electric and diesel urban delivery trucks for a range of drive cycles and electricity generation scenarios, a team from Georgia Tech found that all in all, the life-cycle energy use and GHG emissions of the electric truck are lower than that of the diesel truck, particularly for the frequent stop and low average speed (NYCC- and OCTA-type) drive cycles.
They also found that the total costs of ownership (TCO) of the electric and diesel trucks are similar. Over an array of possible conditions, the median TCO of electric trucks is 22% less than that of diesel trucks on the NYCC. However, the cost-competitiveness of the electric truck diminishes in drive cycles with higher average speed. Battery replacement along with EVSE will also greatly affect the relative TCO of the electric truck. The study is published in the ACS journal Environmental Science & Technology.
CEPS task force report identifies tightening emissions standards as key policy to hit EU 60% reduction in transport GHG; full life-cycle emissions optimal metric
July 01, 2013
The report from a task force assembled by the CEPS (Centre for European Policy Studies), a Brussels-based think tank, on European transport policy has concluded that the EU’s goal of a 60% greenhouse gas (GHG) emissions reduction in the transport sector in 2050 compared to 1990 levels is possible, but at a cost.
Achieving the goal will require a comprehensive policy strategy that needs to be both “credible and adequate”, the report found. Credibility requires beginning to implement policies now—i.e. measures such as standards, taxation or infrastructure development—consistent with the long-term objective. Adequacy requires the measures, in their entirety, to have the potential to meet the target while neither undermining the internal market for transport nor its affordability.
Abt life-cycle analysis of different Li-ion chemistries for PHEVs and EVs identifies opportunities for improving environmental profile of batteries
June 30, 2013
|Generic process flow diagram for lithium-ion batteries for vehicles (color coded to present LCI data sources). Source: “Application of LCA to Nanoscale Technology”. Click to enlarge.|
A recent Abt Associates, Inc. life-cycle study of three Li-ion battery chemistries for plug-in hybrid (PHEV) and battery-electric (BEV) vehicles generated a number of findings and identified opportunities for improving the environmental profile of Li-ion batteries for use in plug-in and electric vehicles.
The study, carried out through a partnership with EPA, the US Department of Energy, the Li-ion battery industry, and academicians, was the first life-cycle assessment to bring together and to use data directly provided by Li-ion battery suppliers, manufacturers, and recyclers. It assessed three currently manufactured Li-ion battery technologies for EVs and two for a PHEV with a 40-mile all-electric range: lithium-manganese oxide (LiMnO2); lithium-nickel-cobalt-manganese-oxide (LiNi0.4Co0.2Mn0.4O2, Li-NCM); and lithium-iron phosphate (LiFePO4). In addition, a single-walled carbon nanotube (SWCNT) anode technology for possible future use in these batteries was assessed.
Study finds climate impact of long distance trip can vary by factor of 10 depending upon mode, efficiency and occupancy
June 27, 2013
A team from Austria and Norway has found that the climate impact from a long-distance trip (500–1,000 km, or 310–621 miles) can easily vary by a factor of 10 per passenger depending on mode choice, vehicle efficiency, and occupancy. Among the findings of the study, published in the ACS journal Environmental Science & Technology, is that a car’s fuel efficiency and occupancy are central to whether the impact from a trip is as high as from air travel or as low as from train travel.
With only one passenger in a car, corresponding to 20−25% occupancy, the climate impact is at the level of an average air trip, whereas a car with three or more passengers, 60% occupancy or more, it is at the low level of average trains or coaches. A notable exception is for the small diesel car; with two passengers ( i.e., 50% occupancy), the specific climate impact is lower than for an average train or bus trip.
Ford LCA harmonization study clarifies benefits of lightweighting for vehicle life cycle energy use and GHG emissions
May 29, 2013
|Correlation between weight reduction and life cycle primary energy demand for (a) component and (b) total vehicle scenarios. Credit: ACS; Kim and Wallington. Click to enlarge.|
While reducing vehicle weight (lightweighting) by replacing steel and iron with alternatives such as aluminum, magnesium, and composites decreases fuel consumption and greenhouse gas emissions during vehicle use, it can increase energy consumption and GHG emissions during vehicle production.
Hyung Chul Kim and Timothy J. Wallington at Ford Motor’s Systems Analytics and Environmental Sciences Department set out to clarify the lifecycle benefits of vehicle lightweighting in a meta-analysis of previously published life cycle assessments (LCAs). While numerous studies assay the benefits of lightweighting, the wide variety of assumptions used makes it difficult to compare results from the studies, the pair noted in their paper, published in the ACS journal Environmental Science & Technology.
New open-source lifecycle analysis tool for oil production using field characteristics
May 25, 2013
|Schematic chart showing included stages within OPGEE. El Houjeiri et al., Supplemental Information. Click to enlarge.|
A team from Stanford University and the California Air Resources Board (ARB) has developed a new open-source lifecycle analysis (LCA) tool for modeling the greenhouse gas emissions of oil and gas production using characteristics of specific fields and associated production pathways. The team describes the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) in a paper in the ACS journal Environmental Science & Technology.
Existing transportation fuel cycle emissions models are either broad—i.e., lacking process-level detail for any particular fuel pathway—and calculate nonspecific values of greenhouse gas (GHG) emissions from crude oil production, or are not available for public review and auditing, the authors note.
Researchers propose evaluating alt fuel efficiency based on energy rather than volume; impact of ethanol on vehicle efficiency and GHGs
May 17, 2013
|Relative changes in vehicle energy efficiency (VEE) (km/MJ) on ethanol/gasoline blends over those on gasoline for different blending levels. Credit: ACS, Yan et al. Click to enlarge.|
In a policy analysis in the ACS journal Environmental Science & Technology, researchers from the Universities of Cambridge, Exeter and Oxford argue that, due to the increased emphasis on alternative fuels with drastically differing energy densities, vehicle efficiency should be evaluated based on energy rather than volume.
With that as a premise, they go on to show that the efficiency of existing vehicles can be both positively and negatively affected by ethanol content, ranging from −15% to +24%. As a result, they conclude, uncertainties in the net greenhouse gas (GHG) effect of ethanol, particularly when used in a low-level blend with gasoline, are considerably larger than previously estimated. Standard deviations increase by >10% and >200% when used in high and low blends, respectively.
Study finds large-scale ramp-up in biofuel crops could result in warming in some tropical regions, cooling in temperate and polar regions
May 08, 2013
Global land-use changes caused by a major ramp-up in biofuel crops—enough to meet about 10% of the world’s energy needs—could make some regions warmer, according to a new integrated modeling study by researchers from MIT and the Marine Biological Laboratory, Woods Hole.
Using an integrated assessment model that links an economic model with climate, terrestrial biogeochemistry, and biogeophysics models, the team examined the biogeochemical and biogeophysical effects of possible land use changes from an expanded global second-generation bioenergy program on surface temperatures over the first half of the 21st century.