Biomass, has been for most of history of our civilisation the primary energy source powering early human development. This energy supply has taken various forms, including wood and dung for cooking and heating, charcoal for metallurgy, and animal feeds for food and transportation. The scale of energy needed today however far exceeds all past demands; both because of the increasing world population and the energy intensity of modern life compound the need for energy higher than never before. As a result of the distances over which energy is moved and the concentration of population into dense urban centres results in an additional need.
The answer until now has been the development for fuels with a high energy density and insure overall efficiency of use.
Over the past century, the developing world has enjoyed cheap and abundant energy supplies through the adoption of a fossil energy economy. The 1900s have been declared the ''Petroleum Century'', with both positive and negative connotations. The widespread use of petroleum allowed rapid economic expansion throughout the industrialized world, increasing national and personal affluence, and enabled the modern ideal of personal automobile ownership. With expanded automobile ownership came an increasing demand for liquid transportation fuels, a demand that led to a shift in primary production as the 21st century opened, expanding energy demand in the developing nations, especially China and India with their very large populations, resulted in significant competition for access to petroleum internationally.
This increased competition has led to a general upward trend in price and increased market volatility. We can find coal and fossil oil both deep down and close to the surface but the more easily accessible localities getting scarce. We have to go deeper and deeper including into the sea's and oceans to get enough.
Bio-fuels are more expensive due to cost than petroleum products but also have a number of important benefits. And taking everything into accounts including environment and future scarcity of fossil oil not to be dismissed. The use of bio ethanol and bio-diesel as an alternative steadily increases around the world. Accordingly, there have been significantly increasing endeavours on the technology development that facilitate the transformation of bio renewable into transportation fuels.
To meet this end, many technologies have employed sugar- and corn-based biomass for the industrial production of bio ethanol, especially in Brazil and U.S., respectively. While they contributed a lot to the commercialisation process, the viability of the so-called 1st generation bio fuels is somewhat questionable because of their competition with the food supply. The key factor influencing bio fuel efficacy is whether native ecosystems can be maintained or not and the micro and macro algae look now a real possibility.
Algae & seaweed.
The attractiveness of seaweeds and micro algae in public opinion and for policy-makers is not only explained by its potential economic benefit. Seaweeds are also attractive because use can contribute to solving some of the major environmental and social concerns that are dominant nowadays. Society demands that this is done in a sustainable way with combinations of ecosystem services smartly chosen to make them strengthen instead of hamper each other. There is growing consensus that the most promising global-scale biomass solution is represented by micro algae since they are Mother Nature's most efficient practitioners of photosynthesis (the fixation of carbon dioxide), resulting in the highest yields of biomass and oils among all aquatic species, which are in turn an order of magnitude more efficient than terrestrial plants.
The chemical composition of algae makes it suitable for conversion into bio fuels. In general, micro algae are potential sources of bio-oils whilst macro algae or seaweeds are potential sources of carbohydrates for fermentation or thermo-chemical based conversions and include the production of sustainable chemicals.
Micro algae can be cultivated in brackish water on non-arable land, and therefore may not incur land use change, minimizing associated environmental impacts. Utilizing marine biomass, which can be grown in a variety of marine environments including fresh water and salt water, near the shore and offshore avoids the problem of additional land use. Utilizing the marine environment ensures a large cultivation area, limiting competition with other land uses and resources. No matter how effective biomass is for producing ethanol, its benefits quickly decrease if all the tropical forests are being razed to make energy crops, leading to another type of a large amount of greenhouse gas (GHG) emission pathway.
To solve this crisis, a new type of biomass is now being developed and their bio fuels can be produced locally in sustainable systems. The seaweeds (macro algae) be an excellent alternative raw material as a new marine biomass for bio fuel production growing along the shallow coastal area of many countries and easy to cultivate. It mainly consists of polysaccharide complexes of fibre and agar whose basic monomer is glucose and galactose residue, respectively. Generally, there are five major bottom lines for a bio ethanol process to be economically viable: the feedstock must be plentiful, inexpensive, in high energy conversion rate, in low demand for food industry, and finally, has to be cultivated in sustainable systems.
Most seaweed shows very fast growing rate (4 - 6 harvest cycles per year) with high CO2 fixation ability, which is 5 - 7 times higher than that of a land plant. Furthermore, they can be mass cultivated using seawater and free sunlight without any need of nitrogen-based fertilizer which has been a significant source of GHG that also destroys stratospheric ozone. In addition, they do not contain any lignin that has to be eliminated prior to hydrolysis step, which has been a major obstacle in lowering production cost in lignocellulose process. Furthermore, the seaweed has ability to absorb nitrogen and phosphorous thereby purifying sea water which leads to oceans' sustainability.