Second-generation biofuels

Figure 1.11 Proposed model for second-generation biofuels.

Second-generation biofuel technologies make use of a much wider range of biomass feedstock (e.g., forest residues, biomass waste, wood, woodchips, grasses and short rotation crops, etc.) for the production of ethanol biofuels based on the fermentation of lignocellulosic material, while other routes include thermo-chemical processes such as biomass gasification followed by a transformation from gas to liquid (e.g., synthesis) to obtain synthetic fuels similar to diesel. The conversion processes for these routes have been available for decades, but none of them have yet reached a high scale commercial level. 

The same holds true for hydrogen however, biomass yields more kilometres when used via hydrogen in fuel-cell cars than liquid biofuels in ICE cars (see Fig. 7.5). Moreover, as hydrogen is produced via gasification, it is equivalent to second-generation biofuels, as it can use feedstock that does not interfere with the food chain. 

The most promising second-generation biofuel technology - ligno-cellulosic processing - is already well advanced. In Europe, for example, three pilot plants have been established, in Sweden, Spain and Denmark. Other technologies to convert biomass into liquid biofuels (BtL) include Fischer-Tropsch biodiesel and bio-DME (dimethyl ether). Demonstration plants are in operation in Germany and Sweden. 

Second generation biofuels Non-food crops, wheat straw, com, wood, solid waste, energy crop Bioalcohols, bio-oil, bio-DMF, Biohydrogen, bio-Fischer-Tropsch diesel, wood diesel... 

The first biodiesel initiatives were reported in 1981 in South Africa and in 1982 in Austria, Germany and New Zealand. Since then, the production of this alternative fuel has seen enormous developments, particularly in Europe, where it reached 5.7 millions tons in 2007. It is expected to increase further to fulfill the recent decision of the European Parliament to substitute 10% of transport fuels with biofuels by 2020. According to assessments of the European Community, to reach this target, the production of bioethanol, biodiesel and second-generation biofuels should reach 36 Mtep (tep = tonnes equivalents petrol) in 2020. 

Second-generation biofuels. (From http /www.iogen.ca)... 

Since late 2007, the Energy Biosciences Institute in Berkeley has been the center for cooperation between scientists from the University of California and the Agricultural Department of the University of Illinois for the production of fuels from so-called energy crops like switch grass. In this second-generation biofuel project that is financed over a 10-year period with 500 million by oil company BP, biomass is converted with the help of synthetic catalysts, for example, organometallic compounds, in a special solvent medium, better known as ionic liquids, into hydrocarbons with properties close to automotive fuels. 

The development of second-generation biofuels may however require more patience. Some of the most popular biocrop feedstocks seem to belong to what are called "invasive species," better known as "weeds," with a high tendency to escape biofuel plantations and overrun adjacent farms and natural land [66]. One expert stated that investors have often started these new ventures in the expectation to produce biofuels in return and in the not-too-far future. It is understandable that they do not like negative assessments. But clearly this is another example where a proper assessment has to be made and patience needs to be applied. 

Like coal, indigenous first-generation biofuels from Europe are not competitive with the products of large foreign producers. For second-generation technologies, the biomass resources shown in Table 12.5 can be rich sources of either classical biofuels or hydrogen production. 

Although the production of biofuels is of considerable economic relevance, it is also characterized by heated political, ecological, and social debates. Recombinant technologies and second-generation fuels are expected to contribute to a reduction in the dependence on fossil resources and to significantly reduce greenhouse gas emissions ([73], section 12.2). A calculation of emissions yielded 94 for gasoline, 77 for currently available bioethanol, and 11 for cellulosic-based ethanol... 

Biofuels can be classified as first generation when they are produced from fermentation of sugar-based raw materials, second generation if they are produced from feedstocks such as lignocellulose and municipal solid wastes, and third generation when they are formed from algal biomass [314,315]. Currently, the most used biofuels are ethanol and butanol. 

Second-generation biofuels are produced from lignocellulosic materials, e.g. low-value crops and residues from agriculture or forestry " or purpose-grown... 

---