INTRODUCTION
In theory, biofuels should provide an effective means to mitigate CO2 emissions.
The reality of biofuels may be more complex: the production and processing of biofuels need more energy and that may result in positive GHG emissions.Biofuels may also accelerate land-use change and deforestation
The policy initiatives of providing support for production of biofuels are not only the ones induced by concerns about climate change, but also the product of concerns for energy-security, depletion of crude-oil reserve, and farm income.--> there are various biofuel policies and they target multiple objectives
BIOFUELS AND IMPLEMENTATIONS OF INTRODUCING THEM
Biomass: A promising renewable energy source
this form of energy is consumed mostly in non-organization for economic cooperation and development countries (OECD)
from an end-use energy perspective, 58 percent of the renewable energy is consumed by the residual, commercial and public sector mostly for cooking and heating
Biomass and electricity
biomass can be used to produce electricity, and is much more efficient at this than in providing transport energy
biomass to generate electricity, is predicted to have high growth rate
The use of biofuel in the transportation sector
A major use of biofuels is as liquid fuels for transportation. Biodiesel can be produced directly from oil-costaining plants whereas ethanol can be processed from sugar, starch and cellulose.
first-generation biofuels are based on sugar, starch and oilseed crops. Two examples of feedstock for bioethanol are sugar beets and sugarcane
the technology used in the first generation is matured and can be classified into four stages, namely, cultivation and production of raw material, processing into fuel and electricity, distribution and retail and end use.
liquid sources can be used to produce biodiesels.
Unlike the first generation, the second-generation feedstock provide opportunities to use nearly the whole plant for biodiesel production, and not only part of the plants (grains, tubes, stalks)
the large scale of production for biofuels require substantial amounts of arable land and water
An alternative to cellulosic based second generation biofuels are drop-in biofuels, that is, fuels such as synthetic gasoline that can be put into fuel tanks and pipeline with no modification.
The unintended environmental consequences from the introduction and expansion of biofuels
the introduction of biofuels may result in an increase in GHG emissions attributed to the increase in total energy consumption.
GHG emissions from biofuel feedstock production have two primary sources: fossil fuel and land
THE BASIC TRADEOFFS AND RESOLUTION
globalization has led to capital intensification as well as increase in demand for consumer goods and food in developing countries.
Globalization also leads to the increase in the price of energy, which contributed to the emergence of biofuels.
GHG emissions and the introduction and expansion of biofuels
main contributors: energy sources from fossil fuel; deforestation in tropical area; land-use change
reduction: reducing energy consumption, increase energy efficiency, using cleaner energy sources,
Land use changes and introduction and expansion of biofuels
it is important to incorporate dynamic aspect of fossil fuels
Food versus fuel
the food-price crisis might have become more acute with agricultural biotechnology
