Use of Biodiesel in a Transit Fleet

Abstract

The use of biodiesel, made primarily from soybeans and other organic products, merits seri- ous consideration as an alternative fuel. As dependency on foreign oil escalates, use of any energy source that is both renewable and made domestically deserves further investigation. Biodiesel also provides a positive environmental effect, has no real handling or infrastructure considerations, mixes well with diesel, is safe to use, and in some cases is less costly to operate than diesel alone. Nevertheless, successful implementation of biodiesel requires agencies to improve their understanding of how the fuel differs from diesel and the various steps needed to avoid problems resulting from those differences. This synthesis provides readers with the full range of biodiesel benefits and the potential downsides, and offers rec- ommendations for effectively managing the successful implementation of biodiesel. Once the subject is fully understood, agencies can make an informed decision regarding its use. One of biodiesel’s biggest downsides is more of a perceptual one; not so much with biodiesel itself, but the base fuel it is blended with: diesel. Although few understand how clean diesel engine emissions have become over the past 20 years, few have forgotten the sight of buses belching black smoke in the years before regulation. Diesel emissions reductions are im- pressive. For every 100 pounds of particulate matter generated from a diesel engine in 1988, fewer than two pounds are emitted from a comparable 2007 engine. Adding biodiesel made from soy beans and other organic feedstocks can make diesel emissions even cleaner. Although reductions in hydrocarbons, carbon monoxide, carbon dioxide, and particulate matter emissions are not disputed, studies regarding the effect of biodiesel on nitrous oxide emissions show a variety of results and require additional research to be conclusive. In partic- ular, research is needed to quantify the level of emissions generated from newer engines currently equipped with diesel particulate filters, and from engines fitted with nitrous oxide reduction devices needed to meet 2010 emissions requirements. The advantage of being able to order biodiesel, load it into existing storage tanks, and operate diesel buses as normal is actually one of biodiesel’s biggest risks. In actuality, the successful implementation of biodiesel requires a well-conceived management approach that needs time and resources to properly execute. Given the time and resources required to implement other alternative fuels, the considerations needed for biodiesel use are minimal. This synthesis includes findings from an extensive literature search into biodiesel, incorpo- rates the responses of 43 transit agencies to a survey questionnaire, and examines the biodiesel implementation of two transit agencies as case studies. To summarize the findings, using higher concentrations of biodiesel bring with it greater potential for both rewards and problems. The higher the biodiesel concentration, the more effective it is at reducing harmful emissions, lower- ing dependency on foreign oil, and providing jobs domestically. Higher biodiesel concentrations are more susceptible to cold weather problems because of its ability to freeze or gel at higher temperatures than diesel, and are more likely to cause fuel contamination problems because of the fuel’s cleansing effect and incompatibility with certain materials. The good news is that all of the potential problems associated with biodiesel can be resolved through an active fuel management program. The majority of steps needed to successfully implement biodiesel are up-front tasks that, when done properly, result in using biodiesel much like traditional diesel fuel with minimal intervention. Recommendations for the successful implementation of biodiesel include: • Learning about the fuel and its characteristics; • Dedicating the necessary time and resources to developing a thorough biodiesel man- agement plan; • Locating a local biodiesel supplier and ensuring that it has adequate quality control mea- sures for blending and delivery; • Using a biodiesel specification that incorporates recognized performance and quality standards; • Using additives as appropriate to control bacteria growth; • Periodically testing fuel deliveries to ensure quality; • Contacting engine and facility fueling representatives to determine warranty coverage and their recommendations for material compatibility; • Choosing a biodiesel percentage based on local climate and operating conditions, and consider changing percentages during different seasons; • Starting with a small test fleet with smaller biodiesel concentrations (preferably in the spring and summer), and monitoring various vehicle and fuel dispensing conditions; and • Promoting agency use of biodiesel and its benefits with the local community.