To develop advanced technologies in the area of bio-fuels, paving the way for a sustainable solution to the energy crisis, the Department of Biotechnology (DBT), has launched — Pan-IIT Centre for Bioenergy — a virtual centre spread across five Indian Institutes of Technology — Bombay, Kharagpur, Guwahati, Jodhpur, and Roorkee.
The first virtual centre for collaborative research, to be coordinated by IIT Bombay, will focus on the thematic areas of research in advance bio-fuel technologies, according to a release.
Bioenergy is energy derived from biofuels. Biofuels are fuels produced directly or indirectly from organic material – biomass – including plant materials and animal waste.
Overall, bioenergy covers approximately 10% of the total world energy demand. Traditional unprocessed biomass such as fuelwood, charcoal and animal dung accounts for most of this and represents the main source of energy for a large number of people in developing countries who use it mainly for cooking and heating.
Biofuels may be derived from agricultural crops, including conventional food plants or from special energy crops. Biofuels may also be derived from forestry, agricultural or fishery products or municipal wastes, as well as from agro-industry, food industry and food service by-products and wastes.
A distinction is made between primary and secondary biofuels. In the case of primary biofuels, such as fuelwood, wood chips and pellets, organic materials are used in an unprocessed form, primarily for heating, cooking or electricity production.
The most widely used liquid biofuels for transport are ethanol and biodiesel.
Ethanol is a type of alcohol that can be produced using any feedstock containing significant amounts of sugar, such as sugar cane or sugar beet, or starch, such as maize and wheat. Sugar can be directly fermented to alcohol, while starch first needs to be converted to sugar. The fermentation process is similar to that used to make wine or beer, and pure ethanol is obtained by distillation.
Biodiesel is produced, mainly in the European Union, by combining vegetable oil or animal fat with an alcohol. Biodiesel can be blended with traditional diesel fuel or burned in its pure form in compression ignition engines. Its energy content is somewhat less than that of diesel (88 to 95%).
Biodiesel can be derived from a wide range of oils, including rapeseed, soybean, palm, coconut or jatropha oils and therefore the resulting fuels can display a greater variety of physical properties than ethanol.
Most plant matter is composed of cellulose, hemicellulose and lignin, and “second-generation biofuel” technologies refer to processes able to convert these components to liquid fuels. Secondary biofuels result from processing of biomass and include liquid biofuels such as ethanol and biodiesel that can be used in vehicles and industrial processes.
Potential cellulosic sources include municipal waste and waste products from agriculture, forestry, processing industry as well as new energy crops such as fast growing trees and grasses.
As a result second generation biofuel production could present major advantages in terms of environmental sustainability and reduced competition for land with food and feed production. It could also offer advantages in terms of greenhouse gas emissions.
Various techniques are currently being developed to produce second generation biofuels. However, it is uncertain when such technologies will enter production on a significant commercial scale.
The conversion of cellulose to ethanol involves two steps. The cellulosic and hemicellulosic components of the plant material are first broken down into sugars, which are then fermented to obtain ethanol. The first step is technically difficult, although research continues on developing efficient and cost-effective ways of carrying out the process. Lignin cannot be converted to ethanol, but it can provide the necessary energy for the conversion process.
Gasification is a technique that converts solid biomass such as wood into a fuel gas. Gasifiers operate by heating biomass to high temperatures in a low-oxygen environment releasing an energy-rich gas. This gas can be burned in a boiler, used in a gas turbine to generate electricity.
Third generation Bio-fuels
Algae and aquatic biomass has the potential to provide a new range of “third generation” biofuels, including jet fuels. Their high oil and biomass yields, widespread availability, absent (or very reduced) competition with agricultural land, high quality and versatility of the by-products, their efficient use as a mean to capture CO2 and their suitability for wastewater treatments and other industrial plants make algae and aquatic biomass one of the most promising and attractive renewable sources for a fully sustainable and low-carbon economy portfolio.
Algae have the potential to produce considerably greater amounts of biomass and lipids per hectare than terrestial biomass, and can be cultivated on marginal lands, so do not compete with food or other crops. Algae can be cultivated photosynthetically using sunlight for energy and CO2 as a carbon source.
They may be grown in Shallow lagoons or raceway ponds on marginal land (e.g. Sapphire Energy, Aurora BioFuels, Live fuels) or closed ponds (e.g. Green Star). Green Star also produces a micronutrient formula to greatly increase the rate of algal growth.
Aquatic plants, such as Spirodela polyrhiza, commonly called Greater Duckweed, have low levels of cellulose and lignin and have the potential to be converted to biofuel at a cost competitive with fossil fuels.