Alternative fuels ethanol

Dedicated Vehicles. Only Brazil and California have continued implementing alcohols in the transportation sector. The BraziUan program, the largest alternative fuel program in the world, used about 7.5% of oil equivalent of ethanol in 1987 (equivalent to 150,000 bbl of cmde oil per day). In 1987 about 4 million vehicles operated on 100% ethanol and 94% of all new vehicles purchased that year were ethanol-fueled. About 25% of Brazil s light-duty vehicle fleet (10) operate on alcohol. The leading BraziUan OEMs are Autolatina (a joint venture of Volkswagen and Ford), GM, and Fiat. Vehicles are manufactured and marketed in Brazil. 

In reviewing the fiiU range of health and safety issues associated with all alternative fuels, the California Advisory Board determined that there were no roadblocks that would prevent the near term deployment of either methanol or ethanol, assuming that adequate safety practices were foUowed appropriate to the specific nature of each fuel (14). 

In the United States, in particular, recent legislation has mandated sweeping improvements to urban air quality by limiting mobile source emissions and by promoting cleaner fuels. The new laws require commercial and government fleets to purchase a substantial number of vehicles powered by an alternative fuel, such as natural gas, propane, electricity, methanol or ethanol. However, natural gas is usually preferred because of its lower cost and lower emissions compared with the other available alternative gas or liquid fuels. Even when compared with electricity, it has been shown that the full fuel cycle emissions, including those from production, conversion, and transportation of the fuel, are lower for an NGV [2]. Natural gas vehicles offer other advantages as well. Where natural gas is abundantly available as a domestic resource, increased use... 

In the United States, the leading use of alternative fuels is not as standalone fuels, but as additives to petroleum-based gasoline and diesel fuel. For example, gasoline sold m much of the United States is 10 percent ethanol or 10 percent methyl tertiary butyl ether (MTBE). 

Natural-gas-dcrived fuels arc the most cost-competitive because natural gas does not need to be refined like gasoline and diesel fuel from petroleum (Figure 1). Ethanol, a heavily subsidized alternative fuel, is not as cost-competitive as natural-gas-dcrived fuels. If not for the subsidies and environmental reg-... 

Owing to diminishing fossil fuel reserves, alternative energy sources need to be renewable, sustainable, efficient, cost-effective, convenient and safe.1 In recent decades, microbial production of ethanol has been considered as an alternative fuel for the future because fossil fuels are depleting. Several microorganisms, including Clostridium sp. and yeast, the well-known ethanol producers Saccharomyces cerevisiae and Zymomonas mobilis, are suitable candidates to produce ethanol.2,3... 

The following three sections of this chapter examine how the vapor pressure varies with composition when both components of a mixture are volatile and how that information can be used to separate them by distillation. Distillation, which we first encountered in Section G, is used to separate the many compounds that make up petroleum and to purify alternative fuels such as ethanol and methanol. 

Chapter one is an overview of the energy evolution. It introduces the technology and emission issues, safety, and alternative fuels such as natural gas, hydrogen gas, methanol, ethanol and fuel cell power. 

In spite of significant problems, many are optimistic about the role of biomass for alternative fuels in the future. The U.S. Department of Energy believes that biofuels from nonfood crops and MSW could potentially cut U.S. oil imports by 15 to 20%. Ethanol industry members believe that the capacity for producing that fuel alone could be doubled in a few years and tripled in five years. 

Technological changes in the manufacture of power sources are required if they are to run on alternative fuels. The development of alternative fuels depends on automotive manufacturers making alternative fuel engines available while fuel suppliers produce and distribute fuels for these vehicles. Flexible fuel vehicles (FFVs), which are also known as variable fuel vehicles, (VFVs) are designed to use several fuels. Most of the major automobile manufacturers have developed FFV prototypes and many of these use ethanol or methanol as well as gasoline. 

The United States passed the Energy Policy Act in 1992. One goal was to reduce the amount of petroleum used for transportation by promoting the use of alternative fuels in cars and light trucks. These fuels included natural gas, methanol, ethanol, propane, electricity, and biodiesel. Alternative fuel vehicles (AFVs) can operate on these fuels and many are dual fueled also running on gasoline. 

Similar actions are to be observed in other parts of the world, increasingly with the objective of diversifying the fuel supply in the transport sector. Examples are in Brazil, which has the world s most developed biofuel industry, and where a 25% blend (mainly ethanol) is mandatory, or the Alternative Fuel Standard (AFS) at federal level in the USA, or various biofuel mandates being introduced at state level (see also (EC, 2006b)). 

Today ethanol and biodiesel (FAME) are the most common biofuels. Alternative fuels from fossil energy sources are mainly LPG and CNG. Synthetic gasoline and diesel from coal (CTL) and natural gas (GTL) are produced mainly in South Africa. Electricity used in battery-electric vehicles plays a minor role today. The fuel consumption for road transport in the world today amounts to about 65 700 PJ per year (IEA, 2006a) in total, the share of alternative fuels for transport at the time of writing was about 2.7% (Table 7.24). 

A variety of alternative fuels, including LPG, CNG, ethanol, methanol, as well as electricity, have been implemented on a small scale in the USA, but with limited success - the total number of alternative fuelled vehicles remains less than 1 % of the total fleet (Davis and Diegel, 2007). The largest alternative fuel used in the USA is ethanol derived from corn, which is currently blended with gasoline up to 10% by volume in some regions, and accounts for 3% of US transportation energy use. 

There is the possibility of using other available fuels such as light distillates, ethanol, anaerobic digester gas, biomass, and refuse-derived fuel. However, these fuels apply to niche market applications. Fuel cell application here, if practical, will evolve from and after widespread uses. Users may require an alternate fuel, probably natural gas. 

Figure 4.1 shows the whole sale prices of a number of possible alternative fuels on an energy equivalent basis compared to conventional gasoline (AlCHE, 1997). Only compressed natural gas (CNG) and liquid petroleum gas (LPG) appear to have some economic advantage relative to gasoline while ethanol, methanol and electricity are at a severe economic disadvantage (Piel, 2001). 

Gasoline Ethanol Methanol Fig. 4.1 Economics of gasoline alternative fuels... 

Alternative fuels Liquefied petroleum gases (LPG), Ethanol, 85% (E85), Ethanol, 95% (E95), Methanol, 85% (M85), Methanol, neat (MlOO), Compressed natural gas (CNG), Liquefied natural gas (LNG), Biodiesel (BD), Hydrogen, and Electricity... 

Alternative fuels can be used to power a fuel cell such as hydrogen, methane, natural gas, methanol, ethanol, liquehed petroleum gas and landfill gas, which can be produced from renewable energy sources such as biomass and wind. 

Environmental concerns have been raised in recent years dealing with greenhouse gases produced from the transportation industry. A contributing cause of these emissions is the combustion of fossil fuels such as diesel, gasoline and oil. A strong enviromnental initiative has pushed for the development of alternative fuels such as ethanol and biodiesel in pure and blended forms (Demirbas, 2008). 

---