Photosynthesis Power

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Abstract

Abstract

Almost all energy sources on Earth are derived from theSun. Many people believe photovoltaic is the future ofhuman energy. This idea is strengthened by manyscience-fiction movies and books where future cities areportrayed with spires clad in shiny photovoltaic panels.However, from the biology point of view, photosynthesisseems to be a more efficient process of energy

conversion. It has been evolved and optimized by naturethrough millennia. Today technology allows biomass tobe converted into useful energy through differentprocesses such as thermal, chemical or biochemicalconversions which result in different form of energy.Algae, with considerable advantages, is argued to be animportant source of human energy in near future.

Biodiesel from Algae:

Photosynthetic Power 3GARC6840 Renewable Energy

Hoang Kien TRAN. March Studies. 2010


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Figure 2: Algae Biodiesel Production Process

3. Economic Biodiesel from Algae

3.1. Current Algae Biodiesel Production Process

Among algae fuel products, the most common is bio-diesel. Acomplete biodiesel production from algae includes 5 stages:cultivation, harvesting, biomass processing, oil extraction andbiodiesel production by transesterification (Fig. 1).

Cultivation and Harvesting: In order to grow at ideal rate, algaeneed to be provided adequate temperature, sunlight and nutrients.Other elements can affect algae growth are content of O2, CO2,pH, chemicals, appearance of other biotic factors like bacteria or

virus. Algae can be cultivated in different systems, like open pondsor closed environment like photo-bioreactors (PBRs). Compared tothe closed reactors, open ponds has lower cost to build and highercapability in volume and durability. However, open ponds can beaffected by changes in weather and other contaminators.

PBRs are more flexible and allow adjustments to suit thecharacteristics of different algae species. According to design,PRBs have better control of conditions and growth, prevent CO2

and water lost while restrict contamination from outside. They canalso allow higher densities and concentrations; therefore possesshigher productivity (Mata et al, 2010). However, PBRs are not yetconsidered a superior technology to open ponds, due to the smallscale; high installation and operation cost; technical setback likeleakage, overheating and bio-foul. Future scenario of algae cultureis the combination of both technologies, where and which isdecided based on the conditions of the site.

Biomass Processing and Oil Extraction: biomass processinginvolves the dehydration of biomass, like the application of sun-drying, spray-drying, or drum-drying. Oil is then extracted frombiomass for biodiesel production, originally in form of lipids andfatty acids using solvents. General solvents used are hexane,ethanol (96%), or a hexaneethanol (96%) mixture, which canextract to 98% fatty acids from biomass (Hartman, 2008). Newextraction methods including the use of ultrasonic and microwave

are being studied. The experiments in these method result higherefficiency in oil extraction and reduce the chemical required to beadded.


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industrial activities wastewater treatment can effectivelymitigate industrial CO2 emission, which contributes to 15% oftotal world CO2 emission.

4.4. Market

Currently, Energy Policy Act of 2005 in USA and RenewableTransport Fuel Obligation in Europe demands that a proportionof renewable fuel must be included in all transportation fuel.Applied on diesel market, it means that 5% must be biodiesel.Global Biofuel Market Analysis (2008) from Bharat BookBureau, India estimated that by 2017, global biodiesel industrywill grow to 3,900 million gallon. It also stated that biofuelmarket will grow to 12.3%. This information anticipates a good

future market for algae fuel production, to the next fewdecades.

Figure 5: Diesel and Crude Oil prize

When the cost-effectiveness

mathematic is solved, there is nothing

could prevent bio-fuel from taking

over conventional petroleum based

fuel.

Compared to other sources in cost-

effectiveness issues and

environmental impacts, algae has thepotential to reign as the major source

of bio-fuel feedstock.

Attracting considerable amount of

concern and investment, algae fuel

industry is preparing to bloom in this

century.

However, much more efforts need to

be done before algae fuel could totally

get into current energy infrastructure

system. "There needs to be policy

work done to incorporate these new

concepts like algae, which is an

organism that actually consumes

large amounts of carbon in the

process of creating a liquid

transportation fuel," said Tim Zenk,

vice president of corporate affairs at

Sapphire. (2009)


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5. Conclusion

The rising energy consumption and environmental issues, the foreseen depletion of fossilfuel encourage the world to consider renewable alternative energy sources. Biofuel isconsidered the most reasonable alternation for conventional petroleum fuel. Derived frombiomass, biofuel is renewable and contributes to the GHG reduction in global scale.

Algae have many qualities to serve as the feedstock for biofuel production, especiallybiodiesel. They have higher oil yield per mass, higher productivity per area unit and rapidgrowth rate than other biodiesel sources. They can be cultivated in wastewater andsaltwater, thus reduce impact on arable land and fresh water for agriculture. Throughphotosynthesis, they fix carbon dioxide and produce oxygen, using contaminants in wateras nutrients.

Biodiesel from algae has a significant setback in competency to petroleum diesel, which isthe high cost in processing. If this gap will somehow be filled, algae biodiesel will becommercially viable and able to replace diesel in the market. A particular technology,presented by a group of researchers from United Environment and Energy LLC, is said tobe able to solve this problem. Using solid catalyst in its transesterification process, theresearchers claimed to be able to reduce at maximum 40% of processing cost. If thistechnology should be applied widely, it has the potential to make biodiesel from algae thealternative fuel for fossil diesel, contributing to global energy security and environmental

sustainability.


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Photosynthesis Power