Hybrid Or Biodiesel?
So, in thinking about whether biodiesel or hybrids are greener, letâ€™s first take a step back. Where do we want to be by year 2025 in terms of fuel economy? By 2050? For simplicity, letâ€™s make some assumptions using targets batted around by greenhouse gas reduction frameworks - 50% reductions by 2025 and 90% by 2050. Letâ€™s also hold this percentage to cars and light-trucks/SUVâ€™s in similar proportions, for simplicity sake. Using data from the US Department of Energyâ€™s Energy Information Administration website for 2005, we see that the average passenger car travels about 12,375 miles per year using 541 gallons of gasoline for a fuel economy of 22.9 miles / gallon. Letâ€™s take passenger cars first. In order to reduce fuel consumption by half, from the current 22.9 miles per gallon, we need to get an average of 45.7 miles to the gallon. That is at or below the current models of Toyota Prius and Honda Civic hybrids achieve. See all US hybrid models here. So, by 2050, could a hybrid achieve 228 miles to the gallon? Already, people tinkering with the Prius, adding additional batteries and a plug-in capability, have achieved 100 mpg â€" so 228 over the next 40 years with continuous improvement in engine and battery efficiency seems very reasonable. Click here to learn more about plug-in hybrids. Letâ€™s put aside our feelings about SUVâ€™s for a minute, and examine the current batch of hybrids on the market â€" their combined Highway/City fuel economies range from 34 miles per gallon, the Ford 2-Wheel Drive Escape down to 29 miles per gallon which includes the rest. So, even with the SUVâ€™s, we could be said to have almost achieved the â€œ50% reductionâ€ from the abysmal current fuel economy of 16.2 mpg. Click here to see all the models. Obviously this isnâ€™t a perfect model. It holds all other emissions and factors constant. Hybrids represent only a small percentage of US cars â€" well under 5% - and SUVs as a percentage of the US fleet continue to grow â€" the above exercise ignores all that. Annual mileage has generally been increasing and overall mpg has remained relatively stagnant. To see the complete data going back to the 1940â€™s, click here. However, it does underscore that solutions to climate crisis are available to consumers, and where we need to get is not impossible. Some of you have expressed concern about the batteries of hybrids. Auto manufacturing and usage are responsible for a significant share of lead pollution, but this is not from hybrid batteries. Lead batteries are too heavy in terms of power-to-weight ratio. Currently, hybrids use nickel metal hydride batteries (NiMHs) batteries for their electricity storage, and significant resources are being put into developing safer, cheaper Lithium based batteries for cars which have an even better power-to-weight ratio. Toyota has included a $200 bounty on their hybrid battery packs to help ensure they are recycled. Nickel and Lithium are not without concern. Like CFLâ€™s, the essential goal with these battery technologies is not to ban usage, but to secure systems to properly handle recycling and waste handling. So, give one point to hybrids for fuel economy. Biodiesel: First, letâ€™s talk about diesel versus gasoline. Have you ever wondered why diesel cars seem to get more miles to the gallon? Well, diesel fuel has more energy in it than gasoline, and the combustion process is slightly more efficient. There are some tradeoffs, however. Diesel releases more air pollution in the form or particulate matter â€" aka that black diesel smoke â€" and NOx components (more on this in a minute). In the US in particular, the smoky diesels of the 1970â€™s and 80â€™s still have a bad reputation. Biodiesel is the renewable sibling of regular fossil fuel based diesel. And it comes with some of the same benefits and drawbacks. In technical terms it is fatty acid alkyl esters, fatty acid methyl esters (FAME), or long-chain mono alkyl esters, which is both non-toxic and biodegradable. Biodiesel can be made from both animal fats and vegetable oils. It can be blended with petroleum based diesel up to B100 â€" 100 percent. To learn more about biodiesel, click here. For B20, 20% biodiesel, there are measurable improvements â€" in PM (- 10.1 %), HC (- 21.1 %), and CO (-11.0 %). CheckÂ here to learn more. These are the emissions from heavy duty engines â€" the researchers did not have enough data to draw the same conclusions from the types of vehicles described above. So, in all categories, except for oxides of nitrogen (NOx), there are measurable improvements. PM â€" is particulate matter â€" and CO is carbon monoxide â€" two air pollutants that cause serious health problems. While biodiesel does reduce fuel economy 1-2% from regular diesel, it also reduces greenhouse gas emissions. The carbon in biodiesel was captured in the formation of soybeans (US) or rapeseed/canola (Europe) when the initial agricultural crop was produced. B100 use reduces carbon dioxide emissions by more than 75% compared with petroleum diesel. Using B20 reduces carbon dioxide emissions by 15%. So, even with the reduced fuel economy, there are still substantial climate emissions reductions. To a certain extent, this is the trade off Europe has made where diesel cars represent almost 50% of the market. They accept slightly more air pollution in exchange for better performance from a climate perspective. In parts of the US with the strictest air quality standards, there are not any new diesel passenger vehicles for sale (although some trucks are available). I am not against these air-quality regulations â€" they have dramatically helped to improve air quality in places like Los Angeles. Automakers have avoided bringing diesels at all to the US because some of the largest markets, like California, are closed. In some states, one can purchase some Mercedes with diesel engines and a Jeep Liberty model. This is supposed to change by 2010 as diesel technology allows for cleaner emissions and ultra-low sulfur diesel fuel becomes more available. For those of you who can purchase a diesel car and use B20, the carbon emissions of your vehicle are equivalent to a gasoline car or regular diesel with fuel economy about 15% greater. Essentially, to hit that 45 mpg mark for 2030 we described above, you need a car that gets about 38 mpg. If you are using B100, about 22.5 mpg. Many people like the idea of turning waste vegetable oil into the fuel for their cars, and can actually do this themselves. The Biodiesel Board has information about where you can find biodiesel and safely handle it. Conclusion: Is there an option for the best of both worlds - what about a hybrid diesel? Hybrid and diesel technologies both add additional costs to a vehicle totally as much as $8,000, and so far, only concept cars have been developed. There is promise, however. A 2003 study from MITâ€™s Laboratory for Energy and the Environment concluded that diesel hybrids represented a better opportunity than hydrogen fuel cells, at least out until 2030. Which brings us to where we started. As you look to your own transportation choices related to automobiles, keep in mind those â€œstretchâ€ goals targeting mpg around 50 now, 100+ for your next purchase, and over 200 mpg for the purchase after that. Other Resources: If you want an good breakdown of the different types of fossil fuels and their uses, visit Environmental Defense. EPA Biodiesel report DOEâ€™s Energy Efficiency and Reweable Energy â€" Biodiesel