Evaluate whether the development of processed biofuels can provide a serious alternative to traditional fossil fuels.The recent development of biofuels around the world can be attributed to a combination of factors, in which the energy crisis plays an important role. The oil price represent that energy crisis has a deep impact on the world. It is argued that the energy crisis is caused by the waste of energy. According to the laws of thermodynamics, energy cannot be destroyed. What people do is to transform it from one state to another (Seitz: 2008). However, sometimes the form is less efficient that results in the waste of energy. Fossil fuel is a typical less useable form, which still take a large proportion of the market. The need that to be independent on fuel and the threat from global warming forces governments to look for alternatives. Scientists are trying hard to find new sources of energy, aiming to increase the efficiency of energy and reduce the pollution brought by fossil fuel on the environment. Biofuels, as a creation of advanced technology, which is cleaner, greener and more efficient than fossil fuel, has become one of the most potential kinds of energy. In order to prove whether biofuels can be a serious alternative to tradition fuels, this essay will give a closer look at three generation biofuels and evaluate their potential and limitation from two criteria: cost and environment.Biofuels is the name given to solid, liquid or gaseous fuels derived from recently dead biological material. Since it seems that biofuels can help people reduce the reliance on fossil fuel and the emission of CO2 into the atmosphere, governments of both industrialized countries and developing countries are encouraging people to increase the production and use of biofuels. However the dramatic growing demand of biofuels has caused various problems associated with the economy, environment and society, which should be treated seriously. In August 2007, a global conference is hold by the United States Department of Agriculture (USDA) at the University of Minnesota and discussed these issues (Ruth, 2008).According to the different feedstock and conversional technology, biofuels can be divided into three generations. The first generation, as the first one stepping on the world stage, has been used more widely than the later generations. Seeds and grains such as wheat are used for the basic feedstock for the production of first generation biofuels. However, at the same time, concerns have been growing about its impact on food security and agriculture. Mr. Ziegler (2007) warned of the consequences of using large areas of arable farming for biofuels feedstock production instead of using for getting food. He claimed that both the United States and Brazil had put heavy investment into the production of biofuels that used food crops. The former aimed to do so to alleviate its reliance on imported fuels, and the latter is to reduce foreign debt. There is a real danger of turning over vast farmlands to grow crops for biofuels, because it will directly lead to food shortage. The consequence is that more people in less develop countries cannot have enough food, which is a significant problem for poor. Many of the problems related to first generation biofuels can be addressed by the production of second generation biofuels. Cellulosic biomass can replace crops and become the new feedstock of biofuels. this has two attractive advantages. Firstly, the waste biomass can create value for society without additional land being required, which reduces the pressure on agriculture. Secondly, cellulosic biomass from fast-growing energy crops such as wood, tall grassed, forestry crops can survive in a wild range of soil types, even in some marginal land where with the help of these crops to prevent erosion. Competing land use will disappear and this will allow much more useful grants to be grown at the same time(Worldwatch Institute (CB), 2007). On the other hand, the feedstock of first generation can only be achieved in the yield with good soils and sufficient water supply. It is obviously that scientists have made progress on the feedstock of biofuels, but from another perspective, the second generation of biofuels also has its own disadvantages. In comparison to first-generation biomass feedstock, cellulosic biomass is more difficult to be broken down and it is not yet clear whether conversional technology will be profitable widely. The feedstock of third generation biofuels is algae and its production is low cost and high yield. Research shows that algae can produce 30 times more energy per acre than can be produced from conventional feedstock requiring land( Eviana Hartman (2008-01-06). While it is argued that the third generation biofuels is the most promising ones, however, excessive expansion of farming algae is a threat to the eco-system in the sea.To some extent, both fr