Microalgae as a sustainable feedstock for biodiesel

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POPULATION OF the world is increasing rapidly and therefore, need for energy is expected to increase by 2 % every year. It is estimated that the energy requirements in 2030 will be 80% higher than that of 2010. A greater part of the world transportation fuel requirements are supplied through petrochemical sources. However, the natural reservoirs of these non renewable fuel resources are depleting rapidly. In such a situation, biofuels emerge as renewable and alternative fuel to petrochemicals. Economic calculations indicate that by 2030, 7% of the world transport will be shifted on biofuels.

Biodiesel is renewable and alternative fuel to petroleum diesel and is produced from vegetable oil or animal fat. It has lower sulfur content and is nearly neutral with respect to Greenhouse Gases (GHG) emissions. In recent decades production of biodiesel from vegetable oil has been encouraged across the globe. Soybean, rape seed, canola and sunflower are used for biodiesel production in USA, Germany, Canada, Argentina and Brazil. However, biodiesel production from edible vegetable oil resources is expensive and ethically not suitable because of their utilization in food products. Therefore, biodiesel production from non edible vegetable oil is an attractive alternative of petroleum based diesel. The oils/fats present in seeds of Jatropha, Neem, Karanja, Rubber seed, Mahua, Silk cotton tree and body cells of microalgae etc are found to be suitable for biodiesel production. These plant species can be easily grown under diverse agro-climatic conditions and on marginal lands.

Among the various non-edible vegetable oil resources, micro-algae are the most plausible option. This is the reason that algae have been extensively researched as sources of fuel due to their high photosynthetic efficiency and their ability to produce lipids, a biodiesel feedstock. Microalgae are mostly photosynthetic organisms that primarily use water, CO2, and sunlight to produce biomass and O2. Nitrogen, phosphorus, mineral salts, trace elements, and silicon are required nutrients for their growth. The above mentioned nutrients are frequently present in municipal, industrial and agriculture wastewater. Therefore, wastewater may provide a cheap source of nutrients for microalgae growth. Microalgal cultivation in wastewater at one hand will help to reduce the risk of environmental pollution and on other hand will result in the production of more economical and sustainable biomass for biodiesel. Mass cultivation of microalgae can be performed on inactive lands using saline water in arid regions, thus avoiding competition for limited arable lands. This conventional production of microalgae provides economic viability of both algal based phytoremediation and biofuel generation strategies.

The material left after extraction of oil from algae can be used as organic fertilizer in agriculture due to its high mineral content. Glycerin obtained as by product of biodiesel can be purified and supplied to various industries (cosmetics and medicines etc) which will further reduce the cost of biodiesel production from algae. Algal biodiesel is a feasible option for establishment of biodiesel industry in developing countries because the biomass yields per acre of algae are significantly greater than other feed stocks (oilseed crops), leading to larger oil yields.

The production of biodiesel in Pakistan is attractive for many reasons in current scenario of energy crisis. Pakistan just spent 8.842 billion USD on importing petroleum products in just seven months (July-January) of the financial year 2012-2013. Moreover, Government is supplying diesel fuel to public on subsidized rates to keep on running transport on roads at low costs. The production of biodiesel reduces the country dependence on imported crude petroleum oil and thus helps in the stability of fuel prices in the market. The commercialization of Biodiesel will help in employment generation in rural areas of country.

These are the reasons which make biodiesel production in Pakistan more attractive. If we produce biodiesel from algae it would be more economical because main purpose of producing biodiesel is not to replace fossils fuels but to balance energy resources.

The micro-algae have capacity to produce sufficient quantity of biodiesel which can reduce the use of petroleum based fuels. Local availability of cheap and sustainable feedstock will result in establishment of biodiesel industry in country which will help in the revenue generation for government. The cultivation of algae does not have to compete for land or water used for cultivation of food crops. Moreover, algae cultivation requires higher amounts of CO2 will help in reducing green house gases and will help in reducing various costs associated with cleaning of the environment.


Published in: Volume 06 Issue 29

Short Link: http://www.technologytimes.pk/?p=13874