The Nexus of Biofuels, Climate Change, and Human Health Workshop Summary (2014) / Chapter Skim
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4 Biofuels Impact on Air, Atmosphere, and Health
4 Biofuels Impact on Air, Atmosphere, and Health
Pages 47-66
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From page 47... ...
BIODISTALLATE FUELS AND EMISSIONS In the first presentation, S Kent Hoekman, research professor in the Division of Atmospheric Sciences at the Desert Research Institute, discussed biodistillate fuels and emissions.
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From page 48... ...
It is also referred to as "green diesel." Co-processed renewable diesel is a form of renewable diesel that is produced by adding vegetable oils or animal fats to feedstocks that are being hydrotreated to produce diesel fuel, creating a single product that is a mixture of bio and fossil HCs. Cellulosic biodiesel fuel, or synthetic biodiesel, is produced by pyrolysis or gasification of lignocellulosic feedstocks, such as grasses and woods.
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From page 49... ...
In the Un nited States, ssoy oil is the main feedstoock used to produce biiodistillates, withw some w waste cookingg oil, sunflow wer oil, and other oils used u as well. In I Europe, thee main feedstoock is rapeseeed, while ini much of thhe rest of the world w palm o il is the domiinant feedstocck.
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Neither petroleum diesel nor renewable biodiesel contains oxygen, while biodiesel is roughly 11 percent oxygen by weight. Another important difference can be found in the energy content of the different fuels.
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Engine improvements have included the adoption of high-pressure, common-rail fuel injection; variable injection timing; and electronic monitoring and control systems. A recently developed emission control system used to reduce particulate emissions is the particulate trap.
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So, it is in that range that it is most important to understand what happens to emissions. Recently, the Desert Research Institute, working on behalf of the Coordinating Research Council, conducted an updated literature review in order to examine more recent and comprehensive information concerning the effects of using biodiesel on engine emissions.
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From page 53... ...
, the base fuel into which the biodiesel was mixed (No. 2 diesel, ULSD, California Air Resources Board [CARB]
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Exhaust emission standards for diesel engines and vehicles have become much more stringent during the past 25 years, which has resulted in the development of advanced emission control systems that reduce emissions dramatically, much more so than a change in the fuel composition to include biodistillate fuels. Determining the effects of fuel-type fleet-wide emissions is difficult because of the variability of engine and vehicle types, test cycles, emissions control systems, and other factors.
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From page 55... ...
The various advanced diesel emission control systems, such as the selective catalytic reduction device and the particulate trap, have been in use for only a couple of years, he reiterated. "I believe that additional research and study monitoring is needed to assess the long-term effects of biodiesel and its impurities on the performance of those systems.
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From page 56... ...
. Noting that there has been quite a bit of this sort of work done on the regional scale in the United States, he said that his talk would be focused instead on some emerging analysis of the regional climate and health impacts of biofuels production in Brazil.
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From page 57... ...
Converting the residue into electricity has greater greenhouse gas benefits than using the residue to produce ethanol, he said, and, furthermore, converting the residue into electricity could have a massive impact on Brazilian energy security. The Level of Direct Emissions After providing that brief overview, Campbell took a more careful look at the emissions caused by the field burning of sugarcane (Tsao et al., 2012)
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58 THE NEXUS OF BIOFFUELS, CLIMATEE CHANGE, AND D HUMAN HEAL LTH a b FIGURRE 4-2 Energy in Brazil: (aa) liquid fuelss production aand consumptiion (2002– –2014)
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. Thhis increasse in emissio ons is due to o the expanssion of the aareas in whiich sugarccane is grown,, so that even with growingg mechanizatiion, the amouunt of fieldd burning hass been increassing.
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projected death rate of operating gasoline vehicles. Campbell noted that there is obviously much uncertainty in the exact number of deaths from the air quality effects of the pre-harvest burning, but from this preliminary analysis there appears to be significant potential for the health impacts to be quite large.
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, including indirect land-use change in the calculations may nearly double the estimated emissions due to the production of biofuels. To put this in perspective, Campbell compared the indirect emissions of PM from biofuels production to the emissions of PM caused by Amazonian deforestation.
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There have been some very simple ballpark estimates of the climate forcing of carbon black that have been public, he said, and applying those estimates implies that field burning "can potentially exceed some thresholds for life-cycle greenhouse gas emissions." However, Campbell said, what is really needed is to run a regional climate model "because the climate forcing from these species varies so much depending on the domain, the time of year, the timing of the emissions, all of these kinds of factors." Thus, the jury is definitely still out on the effects of these carbon black emissions. Carlos Santos-Burgoa from the Pan American Health Organization asked whether there were any changes that could be made to the sugarcane ethanol production process that would improve the emissions.
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From page 63... ...
Al McGartland responded that the EPA does include an analysis of energy security in the ethanol regulations when it sets a mandate. There are a variety of security benefits to ethanol production, he said, including making the economy less vulnerable to the price of oil and potentially decreasing military expenditures in the Middle East if imported petroleum is less vital to the national interest.
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64 THE NEXUS OF BIOFUELS, CLIMATE CHANGE, AND HUMAN HEALTH An audience member elaborated on the importance of persuading decision makers -- and especially the economists who advise them -- that air quality needs to be taken into account as a serious policy concern. "I think that air quality is one of a class of health-related issues that traditionally have been marginalized," he said, "in part because although economists will pay lip service to issues of health and productivity, I'm not sure that the current economic theory really believes it." The result is that economic models often minimize or leave out health considerations.
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From page 65... ...
2011. Effects of biodiesel fuels upon criteria emissions.
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