[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.]
UC Riverside researchers find mixed emissions impact from use of higher ethanol and butanol fuels in FFVs
November 24, 2014
A study by University of California, Riverside researchers found that the use of higher ethanol blends and a 55% butanol blend in port-fueled and direct injection flexible fuel vehicles (FFVs) could lead to emission changes of GHGs, CO, aldehydes, BTEX (monoaromatic hydrocarbons of benzene, ethylbenzene, toluene, m/p-xylene, and o-xylene), and particulates.
In a paper in the ACS journal Environmental Science & Technology, they reported that the higher alcohol fuels would decrease PM mass and number emissions, although current technology direct injection fueling produces higher particle number and soot mass emissions than the PFI fueling as a result of liquid fuel wetting effects and insufficient air fuel mixing. Particulate emissions were clearly influenced by certain fuel parameters including oxygen content, hydrogen content, and aromatics content.
EPA delays issuing 2014 RVO standards for RFS until sometime in 2015
November 21, 2014
The US Environmental Protection Agency (EPA) will not finalize the 2014 applicable percentage standards (the 2014 Renewable Volume Obligations, RVOs) under the Renewable Fuel Standard (RFS) program until sometime next year. In a notice to be published in the Federal Register, the agency said that it intends to take action on the 2014 standards rule in 2015 prior to or in conjunction with action on the 2015 standards rule.
Because of the delay in issuing the 2014 RFS standards, EPA is moving the compliance demonstration deadline for the 2013 RFS standards to 2015. EPA will make modifications to the Moderated Transaction System (EMTS) to ensure that Renewable Identification Numbers (RINs) generated in 2012 are valid for demonstrating compliance with the 2013 applicable standards.
UCLA researchers develop synthetic biocatalytic pathway for more efficient conversion of methanol to longer-chain fuels
November 18, 2014
Researchers at the UCLA Henry Samueli School of Engineering and Applied Science led by Dr. James Liao have developed a more efficient way to turn methanol into useful chemicals, such as liquid fuels, and that would also reduce carbon dioxide emissions. The UCLA team constructed a synthetic biocatalytic pathway that efficiently converts methanol under room temperature and ambient atmospheric pressures to higher-chain alcohols or other higher carbon compounds without carbon loss or ATP expenditure.
Building off their previous work in creating a new synthetic metabolic pathway for breaking down glucose that could lead to a 50% increase in the production of biofuels (earlier post), the researchers modified the non-oxidative glycolysis pathway to utilize methanol instead of sugar. An open-access paper on the research was published in the 11 Nov. edition of the Proceedings of the National Academy of Sciences.
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”.
Ford, GM and AVL researchers argue match-blending a flawed approach to evaluate ethanol-gasoline blends (corrected)
November 06, 2014
(Earlier version attributed the final quote to the research team. Our apologies for the error.)
In a newly published SAE paper, a team from Ford, General Motors and AVL argues that the exclusive use of a match blending approach to prepare ethanol-gasoline blends for regulatory emissions testing “has fundamental flaws”.
This echoes the recent criticism by the Urban Air Initiative (UAI) and the Energy Future Coalition (EFC) that the latest version of the US Environmental Protection Agency’s (EPA) MOtor Vehicle Emission Simulator (MOVES) modeling system for estimating emissions from mobile sources is “seriously flawed” with respect to its reliance on match blending. (Earlier post.)
Researchers enhance yeast thermotolerance and ethanol tolerance; potential for significant impact on industrial biofuel production
October 03, 2014
The yeast Saccharomyces cerevisiae plays a central role in global biofuel production; currently, about 100 billion liters of ethanol are produced annually worldwide by fermentation of mainly sugarcane saccharose and corn starch by the yeast. There are also efforts underway to use the yeast with cellulosic biomass.
Boosting the yield and lowering the cost of fermentative production of biofuel would not only result in a significant immediate financial impact to commercial ethanol operations, but also support cost reductions that would be helpful to advance other advanced biofuels using the same or a similar pathway. However, boosting production has been gated by two key conditions: the ability of the yeast to tolerate higher temperatures, and the ability of the yeast to survive high concentrations of ethanol. Now, two new separate studies report progress on each of those fronts; the findings could have a significant impact on industrial biofuel production. Both papers are published in the current issue of the journal Science.
Emissions study suggests E10 + renewable hydrocarbons a high bioenergy alternative for conventional cars
August 14, 2014
Researchers from VTT Technical Research Center of Finland and Neste Oil analyzed the exhaust emissions from three different spark ignition engine technologies—multipoint fuel injection (MPFI); direct-injection spark-ignition (DISI); and flex-fuel (FFV)—using different biofuels—low- and high-concentration ethanol blends; isobutanol; and biohydrocarbons. They report their findings in a paper in the ACS journal Environmental Science & Technology.
Among their conclusions was that the combination of ethanol or isobutanol with renewable hydrocarbon components (i.e., drop-in biohydrocarbons) could offer an option to achieve a high-bioenergy-content gasoline that is compatible with conventional gasoline-fueled cars (i.e., those limited to a 10% ethanol blend) without a significant change in emissions.
NIST study suggests severe corrosion in underground gasoline storage tanks may require component replacement sooner than expected; 500K USTs in US
July 30, 2014
|Optical micrographs of severe corrosion on steel alloy samples exposed to ethanol and acetic acid vapors—conditions typical of underground gasoline storage tanks—after 355 hours, 643 hours, and 932 hours. Source: NIST. Click to enlarge.|
In recent years, field inspectors in nine states have reported many rapidly corroding underground gasoline storage tank (UST) components such as sump pumps. These incidents are generally associated with use of gasoline-ethanol blends and the presence of bacteria, Acetobacter aceti, which convert ethanol to acetic acid, a component of vinegar. Corrosion can result in failures, leaks and contamination of groundwater, a source of drinking water.
Following up on the inspectors’ findings, a National Institute of Standards and Technology (NIST) laboratory study has demonstrated severe corrosion—rapidly eating through 1 millimeter of wall thickness per year—on steel alloy samples exposed to ethanol and acetic acid vapors. Based on this finding, NIST researchers suggest gasoline stations may need to replace submersible pump casings, typically made of steel or cast iron, sooner than expected.
Ethanol producer to integrate renewable diesel production from corn distiller oil
July 25, 2014
Ethanol producer East Kansas Agri-Energy LLC (EKAE) intends to integrate renewable diesel production at its ethanol plant in Garnett, Kansas. Renewable diesel will be made from the corn distillers oil (CDO) already produced at the plant along with other feedstocks purchased on the market. WB Services is the technology provider for the catalytic renewable diesel process.
Construction on the new facility will begin soon and will be complete in about 12 to 14 months. The plant will be able to produce three million gallons of hydrocarbon fuel per year, with the ability to double that capacity in the future. The plant currently produces some 40 million gallons of ethanol; 200,000 tons of the livestock feed distillers grains; and 5 million pounds of corn oil each year from more than 16 million bushels of locally-sourced corn.
Cummins ETHOS 2.8L optimized E-85 engine demonstrates 50-80% reduction in CO2 emissions in medium-duty truck
July 14, 2014
|The ETHOS 2.8L demo truck. Click to enlarge.|
Cummins has developed an E-85-specific engine and powertrain that reduce carbon dioxide emissions by as much as 80% compared with a baseline gasoline-powered medium-duty truck. The work was jointly funded by Cummins and partners ($3,790,027) in partnership with the California Energy Commission (CEC) ($2,712,140).
The Cummins ETHOS 2.8L is designed specifically to use E-85 (85% ethanol and 15% gasoline). To take full advantage of the favorable combustion attributes and potential of E-85, the engine operates at diesel-like cylinder pressures and incorporates advanced spark-ignition technology. It delivers the power (up to 250 hp / 186 kW) and peak torque (up to 450 lb-ft / 610 N·m) of gasoline and diesel engines nearly twice its 2.8-liter displacement.
Joule first to gain US EPA clearance for commercial use of modified cyanobacteria for fuel production
July 01, 2014
The US Environmental Protection Agency (EPA) has favorably reviewed Joule’s Microbial Commercial Activity Notice (MCAN) for the company’s first commercial ethanol-producing catalyst (a modified Synechococcus cyanobacterium). This clears the catalyst for commercial use at the company’s demonstration plant in Hobbs, New Mexico.
This also marks the first time that EPA has allowed the commercial use of a modified cyanobacterium (although not of other modified microorganisms such as S. cerevisiae, E. coli, T. reesei, etc.). (The full list of EPA notifications under the Toxic Substances Control Act—TSCA—is available here.)
LowCVP reports indicate pathways for meeting renewable energy targets in transportation, decarbonizing fuel to 2030 and beyond
June 18, 2014
|Illustrative impact of the fuel roadmap. Source: LowCVP, Element Energy. Click to enlarge.|
The UK’s LowCVP has published twin reports which set out how the UK could meet its 2020 targets defined in the EU’s Renewable Energy Directive, and proceed on a pathway to decarbonize road transport fuel in the period to 2030 and beyond.
The LowCVP—the stakeholder body which brings government, industry and other stakeholders together to focus on the challenges of decarbonizing road transport—commissioned energy consultancy Element Energy to analyze the UK’s options for meeting the Renewable Energy Directive’s (RED) 2020 transport target which states that at least 10% of the final energy consumption in transport must come from renewable sources. This and the parallel Fuels Roadmap report benefitted from wide industry consultation and explicitly set out to align with existing powertrain roadmaps (including those published by the Automotive Council and the LowCVP).
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.
MSU microbial electrolysis cell produces ethanol from glycerol, reduces wastewater in biodiesel production
May 22, 2014
|The MEC uses syntrophic cooperation within a bacterial consortium (red and green) in the anode chamber to ferment ethanol from glycerol and to remove inhibiting H2. Credit: ACS, Speers et al. Click to enlarge.|
Researchers at Michigan State University have developed a microbial electrolysis cell (MEC) which will allow biodiesel plants to eliminate the creation of hazardous wastes while reducing their dependence on fossil fuel.
The platform, which uses microbes to produce ethanol from glycerol, has the added benefit of cleaning up the wastewater, will allow producers to reincorporate the ethanol and the water into the fuel-making process, said Gemma Reguera, MSU microbiologist and one of the co-authors. The ethanol replaces petrochemical methanol in the biodiesel production. A paper on their work is published in the ACS journal Environmental Science & Technology.
Study finds alcohol mix from biomass-derived syngas could be suitable replacement for ethanol in fuel blending
May 12, 2014
|AlcoMix displays antiknock blending characteristics similar to those of ethanol when blended at various concentrations with non-oxygenated gasoline (RON = 82). Credit: ACS, Rapp et al. Click to enlarge.|
Results of a study by a team from the US and Austria suggest that the primary alcohol mixture (“AlcoMix,” comprising 75% ethanol, 11% 1-propanol, 8% 1-butanol, and 6% 1-pentanol) produced from biomass-based syngas could be used as a substitute for ethanol as a primary fuel or as an antiknock blending component.
The purpose of the study, reported in the ACS journal Energy & Fuels, was to determine whether AlcoMix,the probable outcome of the thermochemical conversion of biomass using Fischer–Tropsch chemistry with synthesis gas, might be a suitable replacement for ethanol in fuel blending as an antiknock blending component for spark-ignited engines.
Study finds São Paulo switch from ethanol to gasoline dropped local ozone levels by 20%, increased CO and nitric oxide concentrations
April 29, 2014
A study by a pair of researchers at Northwestern University found that when fuel prices drove residents of São Paulo, Brazil, to switch from ethanol to gasoline in their flexible-fuel vehicles, local ozone levels dropped 20%. At the same time, nitric oxide and carbon monoxide concentrations tended to go up.
The four-year study by chemist Franz M. Geiger and Alberto Salvo, formerly with Northwestern’s Kellogg School of Management and now an associate professor of economics at the National University of Singapore, is the first real-world trial looking at the effects of human behavior at the pump on urban air pollution. Their paper appears in the journal Nature Geoscience.
Byogy and Avianca launch initiative to accelerate approval of Alcohol-to-Jet (ATJ) fuel
April 25, 2014
|Byogy’s four-step process for the conversion of ethanol to renewable jet fuel. Click to enlarge.|
Byogy Renewables and airline partner Avianca Brasil (earlier post) have launched an initiative to support advanced testing to accelerate the approval by ASTM of Byogy’s alcohol-to-jet (ATJ) fuel. (Earlier post.) The Avianca/Byogy Team will perform advanced Flight Testing using the CFM-56 powered A319 to acquire test data and support an Environmental Impact Study to drive ASTM adoption of Byogy’s ATJ fuel.
Byogy’s proprietary ATJ process converts ethanol to a full replacement renewable jet fuel that does not require blending, and also demonstrates performance characteristics better than jet fuel produced from oil. Byogy’s jet fuel is not an additive, but instead, a full replacement standalone fuel, and hence can be used at any blend ratio up to 100%, the company says.
ARB posts 5 new LCFS pathways; two renewable diesel
April 15, 2014
California Air Resources Board (ARB) staff has posted five new and one revised Low Carbon Fuel Standard (LCFS) fuel pathway applications to the LCFS public comment website. The new pathways include two renewable diesel pathways; two biodiesel pathways, and one corn ethanol pathway. The revised package is for corn oil biodiesel.
The renewable diesel proposals both come from Diamond Green Diesel (DGD) in Louisiana, using used cooking oil (UCO) as a feedstock; the proposals differ in the mode of shipment to California: one by rail, one by ship.
Stanford researchers develop copper-based catalyst that produces ethanol from CO at room temperature; potential for closed-loop CO2-to-fuel process
April 11, 2014
Researchers at Stanford University have developed a nanocrystalline copper material that produces multi-carbon oxygenates (ethanol, acetate and n-propanol) with up to 57% Faraday efficiency at modest potentials (–0.25 volts to –0.5 volts versus the reversible hydrogen electrode) in CO-saturated alkaline water.
The material’s selectivity for oxygenates, with ethanol as the major product, demonstrates the feasibility of a two-step conversion of CO2 to liquid fuel that could be powered by renewable electricity, the team suggests in their paper published in the journal Nature. Ultimately, this might enable a closed-loop, emissions free CO2-to-fuel process.
Worldwatch Institute: global biofuel production fell in 2012 for first time since 2000
April 10, 2014
|World ethanol and biodiesel production. Source: Worldwatch. Click to enlarge.|
In 2012, the combined global production of ethanol and biodiesel fell for the first time since 2000, down 0.4% from the figure in 2011, according to the Worldwatch Institute’s latest Vital Signs Online report. Global ethanol production declined slightly for the second year in a row, to 83.1 billion liters (22 billion gallons US), while biodiesel output rose fractionally, from 22.4 billion liters in 2011 to 22.5 billion liters (5.9 billion gallons US) in 2012. Biodiesel now accounts for more than 20% of global biofuel production, according to the report.
Biofuels for transport—essentially ethanol and biodiesel—account for about 0.8% of global energy use, 8% of global primary energy derived from biomass, 3.4% of global road transport fuels, and 2.5% of all transport fuels.
Gevo transitioning Luverne plant to produce both isobutanol and ethanol; “side-by-side” configuration
March 26, 2014
Bio-isobutanol company Gevo, Inc. is transitioning its Luverne plant to the production of both isobutanol and ethanol. Gevo said that its decision—announced during its 4Q 2013 earnings call—to transition to the simultaneous production of both products is a direct result of (1) the steady progress made in executing its flexible production technology strategy and (2) the current high ethanol margin environment.
Producing both ethanol and isobutanol allows Gevo to fully utilize the Luverne plant and increase cash flow as Gevo continues to commercialize its isobutanol production capabilities.
Vertimass licenses ORNL ethanol-to-hydrocarbon conversion technology; overcoming the blend wall with drop-in fuels
March 07, 2014
Vertimass LLC, a California-based start-up company, has licensed an Oak Ridge National Laboratory (ORNL) technology that directly converts ethanol under moderate conditions at one atmosphere without the use of hydrogen into a hydrocarbon blend-stock for use in transportation fuels.
The technology developed by ORNL’s Chaitanya Narula, Brian Davison and Associate Laboratory Director Martin Keller uses an inexpensive zeolite catalyst to transform ethanol into a blend-stock consisting of a mixture of C3 – C16 hydrocarbons containing paraffin, iso-parrafins, olefins, and aromatic compounds with a calculated motor octane number of 95. Fractional collection of the fuel product allows for the different fractions to be used as blend-stock for gasoline, diesel, or jet fuel.
Navigant Research forecasts 58% growth in global biofuels consumption by 2022; biodiesel and drop-in fuels gain market share
February 05, 2014
In a new report, “Biofuels for Transportation Markets”, Navigant Research forecasts that global demand for biofuels in the road transportation sector will grow from representing almost 6% of the liquid fuels market in 2013 to roughly 8% by 2022. Of that 8%, 8% will consist of advanced drop-in fuels, according to the research firm. Navigant forecasts that global biofuels consumption in the road transportation sector will grow from more than 32.4 billion gallons per year (BGPY) in 2013 to more than 51.1 BGPY in 2022—an increase of 58%.
Overall, Navigant forecasts that global retail sales of all liquid fuels for the road transportation sector will grow from more than $2.6 trillion in 2013 to more than $4.5 trillion in 2022 (73% growth).
ICCT study concludes no technical barriers to use of higher blends of ethanol
A team at the International Council on Clean Transportation (ICCT) has released a paper assessing technical barriers to the use of higher blends of ethanol. Broadly, the study by Stephanie Searle, Francisco Posada Sanchez, Chris Malins, and John German concludes that (a) technical barriers do not prevent the use of higher blends of ethanol, and (b) slow uptake of blends such as E15 and E85 is due to other factors, including high cost, legal and warranty issues, and consumer awareness and acceptance.
The paper was commissioned by the Bipartisan Policy Center (BPC) as part of a yearlong effort aimed at fostering “constructive dialogue and action” on reforming the Renewable Fuel Standard (RFS2). BPC is convening a diverse RFS advisory group to discuss opportunities for reform, hosting public workshops to solicit broad input, and ultimately publishing viable policy options based, in part, on the advisory group’s deliberations. The ICCT paper is one of five background papers to be released on different aspects of the problem. The others are:
Audi testing finds e-ethanol and e-diesel produced by Joule often perform better than conventional counterparts
February 03, 2014
|Audi investigating its e-fuels in an optical research engine using laser-induced fluorescence. Click to enlarge.|
Audi testing of synthetic ethanol (Audi e-ethanol = Joule Sunflow-E) and synthetic diesel (Audi e-diesel = Joule Sunflow-D), produced in partnership with Joule (earlier post) in a pressure chamber and optical research engine has shown that the Audi e-fuels often perform better than their conventional counterparts.
Joule’s Helioculture platform uses engineered microorganisms directly and continuously to convert sunlight and waste CO2 into infrastructure-ready fuels, including ethanol and hydrocarbons (n-alkanes) that serve as the essential chemical building blocks for diesel.
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.
Oak Ridge Lab study finds E30 blend and EGR can deliver significant efficiency improvements in optimized SI engines
January 17, 2014
Researchers at Oak Ridge National Laboratory’s National Transportation Research Center (NTRC) report that an E30 (30% ethanol) mid-level ethanol blend shows promise as a means for significant improvement in vehicle efficiency in optimized spark-ignited (SI) engines. Results of the study by Derek Splitter and Jim Szybist suggest that it could be possible to implement a 40% downsize + downspeed configuration (1.2 L engine) into a representative midsize sedan using this combination of optimized engine and mid-level alcohol blend.
As an example, for a midsize sedan at a 65 mph (105 km/h) cruise, estimated fuel efficiency of 43.9 mpg (5.4 l/100 km) with engine-out CO2 of 102 g/km could be achieved with similar reserve power to a 2.0 L engine fueled with regular gasoline (38.6 mpg/6.1 l/100km, engine out CO2 of 135 g/km). The data suggest that, with midlevel alcohol–gasoline blends, engine and vehicle optimization can offset the reduced fuel energy content of alcohol–gasoline blends and likely reduce vehicle fuel consumption and tailpipe CO2 emissions.
Sandia study finds meeting RFS2 requirements unlikely without stronger enforcement mechanism; the importance of drop-in biofuels
January 06, 2014
Even if well-known technology, infrastructure, economic and political challenges in meeting the biofuel requirements of the RFS2 mandate are overcome, it is “highly unlikely” that the light-duty vehicle parc will be capable of consuming the RFS2 (Renewable Fuel Standard) mandated volumes of biofuels, according to a new analysis by a team from Sandia National Laboratory.
The Sandia researchers showed that the key to meeting the RFS2 targets is the fuel price differential between E85 fuel and conventional gasoline (low ethanol blends), so that E85 owners refuel with E85 whenever possible. In other words, RFS2 will be satisfied if gasoline becomes significantly more expensive than E85 on a per energy basis. This is, however, the opposite of historic pricing trends, and suggests that policy intervention of a stronger enforcement mechanism will be required to meet RFS2 targets by creating market conditions necessary for greater biofuel consumption.
Ford researchers report detailed study of the effect of different ethanol blend levels on emissions from FFVs
December 23, 2013
A team at Ford Motor Company’s Research and Innovation Center in Dearborn conducted a detailed study of the effect of ethanol blend level in emissions, using a 2006 model Mercury Grand Marquis flexible fuel vehicle (FFV) operating on E0, E10, E20, E30, E40, E55, and E80 on a chassis dynamometer. The study thus included the current predominant market fuel (E10); a range of possible future midlevel ethanol blends (E20−E40); and the new range for high-level ethanol blends (E55, E80).
The number of blends they studied is about twice that of previous studies, and delivers a more detailed picture of the effect of ethanol blend level on emissions. Further, they reported data for engine-out emissions and tailpipe emissions; operating temperatures (engine-out and catalyst); and ethanol concentrations used in the engine control strategy. Comparing these data allows for differentiation between fuel chemistry and engine calibration effects—the two general mechanisms by which increased ethanol content in fuel affects the emissions.
ARB posts six new LCFS pathway applications for comment; new PFAD biodiesel approach
December 18, 2013
The California Air Resources Board (ARB) staff has posted six new Low Carbon Fuel Standard (LCFS) pathway applications to the LCFS public comment web site: corn ethanol; molasses ethanol (from Brazil); palm fatty acid distillates (PFAD) to biodiesel; and landfill gas to LNG, L-CNG, and CNG.
The LCFS requires oil producers, importers and other fuel providers gradually to reduce, on a full-fuel lifecycle basis, the carbon intensity (CI) of their transportation fuel mix (measured in gCO2e/MJ) by from 0.25% in 2011 to 10% by 2020. (Earlier post.) The current batch of new applications covers quite a range of carbon intensity in the fuels: from 88.69 gCO2e/MJ for the corn ethanol, down to 10.64 gCO2e/MJ for biodiesel produced from PFAD—the first such pathway considered for the LCFS program. The baseline carbon intensity for gasoline in the LCFS lookup table is 99.18 gCO2e/MJ and 98.03 gCO2e/MJ for diesel.
Rice study: higher ethanol blends require different approach to deal with vapor intrusion in buildings; extreme event, low probability
December 16, 2013
A study lead by researchers at Rice University suggests that current approaches to manage the vapor intrusion risk into buildings in the vicinity of conventional fuel spills might need to be modified when dealing with some higher ethanol blend fuel (i.e., E20 up to E95) releases. The study is published in the ACS journal Environmental Science & Technology.
The basis of the concern is that ethanol-blended fuel spills usually stimulate methanogenesis in the subsurface, which could pose an explosion risk if methane accumulates in a confined space above the ground where ignitable conditions exist. The ethanol-derived methane may also increase the vapor intrusion potential of toxic fuel hydrocarbons (e.g., benzene) by stimulating the depletion of oxygen by the methanotrophs, and thus inhibiting aerobic biodegradation of hydrocarbon vapors.
Mascoma bioengineered yeasts have produced more than 1B gallons of ethanol
December 11, 2013
Mascoma Corporation, a leading provider of bioconversion technology, announced that its consolidated bioprocessing technology (CBP) has been used to produce more than 1 billion gallons of corn ethanol. The company said that this represented a key commercial milestone for its MGT yeast products including TransFerm and TransFerm Yield+. (Earlier post.)
Using its proprietary CBP technology platform, Mascoma has developed bioengineered yeasts to reduce costs and improve yields in the production of renewable fuels and chemicals. Mascoma’s first commercial application of its technology platform are its Mascoma Grain Technology (MGT) yeast products, which are drop-in substitutes for existing yeasts designed to improve the economics of corn-based ethanol production.
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.)
NREL study probes emissions impact of butanol-gasoline blends in light-duty vehicles
November 26, 2013
|Summary of significant emissions results from the fuel testing. Credit: ACS, Ratcliff et al. Click to enlarge.|
Results of a study led by a team from the National Renewable Energy Laboratory on the impact of butanol-gasoline blends on light-duty vehicle emissions suggest that widespread deployment of n-butanol or i-butanol in the gasoline pool could result in changes to the estimated emissions of alcohols and carbonyls in the emissions inventory. Given equivalent deployment of butanols and ethanol, the results suggest emissions of unburned alcohols would decrease, but carbonyl emissions would increase; some of these compounds have poorly understood health effects, they note.
The carbonyls acetaldehyde and formaldehyde are classified as carcinogens or probable carcinogens by the National Institute for Occupational Safety and Health (NIOSH), International Agency for Research on Cancer, and the EPA. NIOSH considers butyraldehyde to have similar reactivity and mutagenicity to acetaldehyde.