ALGAE - SOURCE OF ENERGY
SK ANSARI, SEEMA ANSARI
July 05 - 11, 2010
Algae that are found both in marine and freshwater can become an effective source of feedstock for the production of bio-fuel.
The depletion of traditional sources of energy and climatic change triggered by excessive use of fossil fuels need innovative thinking both on social and scientific fronts.
Bio-fuel from algae is of great importance to meet mounting needs of energy in future and to prevent impact of fossil fuel consumption on the environment.
There are numerous kinds of algae that can be used to produce bio-diesel or bio-fuel. While the photosynthesis process in algae is similar to that of other plants, this organism is generally more efficient in converting solar energy to biomass.
Various kinds of algae have different capacity to produce energy oils. Macrocystis that is found near shore gives better results and yearly biomass production of more than 30 tonnes per hectare.
Macroalgae commonly known as seaweed or kelp are fast growing plants that can reach a considerable size of up to 60 meter in length while microalgae is the most primitive form of photosynthetic organism. Algae with low cost and high yields can be grown practically at every place if there is enough sunshine.
ALGAE IN PAKISTAN
Algae from Pakistan are capable of producing oil 30 times more than that by other crops.
Pakistan has about 27 million acres of saline lands which are fundamental to make algae sprout. Algae need salts, carbon dioxide, and sunlight to grow and produce oil. Ground saline water of some saline lands can also be used to irrigate algae.
Algal species can be collected from temporary and permanent ponds of Thatta, Dadu, Larkana, Hyderabad and Kharipur districts of Sindh while in Karachi there are several natural ponds for this organism. Clifton, Manora, Sandspit, Hawks Bay, Somar Goth, Buleji, Paradise Point, Pacha, Naugaza Mazar and Cape Monze are some of the places. The freshwater and brackish water algae are collected from pools, ditches, lakes, irrigation canals, riverside ponds and other water reservoirs. The ecological study of Algal Flora of the Jhelum River in Azad Kashmir found 134 species in the area.
TRANSPORT FUEL FROM ALGAE
Bio-fuel is important to mitigate greenhouse gas emissions. It also provides substitutes to petroleum, natural gas, coal, hydro, and nuclear sources of energy. For large scale production in algae farms, CO2 could be obtained from a number of sources, especially fossil fuel-burning power plants. This would provide a practical approach for recycling CO2 into a useable fuel. Japan, which is extremely dependent on energy imports, is actively pursuing this approach to extend its domestic energy production.
One of the simplest ways to use biomass generated from macro or microalgae is to produce methane. Because of the high water content of algae, gasification requiring drying of the material is not attractive. Anaerobic digestion - which is anyway conducted in water - is therefore more adaptable. The methane generated can than be used in the same way as natural gas to produce methanol. More research is needed, however, to provide a better understanding of the biology of aquatic organisms and to identify the best species and growing conditions for optimal conversion of solar energy into biomass.
A hectare pond filled with algae can produce 15,000 to 80,000 liters of vegetable oil a year whereas about 6,000 liters of palm oil can be squeezed out of a hectare a year.
TYPES AQUATIC HABITATS Green Algae Fresh and salt water Diatoms, golden-brown algae Fresh and salt water Euglena Fresh water Brown algae Salt water Red algae Fresh and salt water Yellow-Green algae Fresh and salt water
Oxygen is produced during the photosynthetic process. At night, in the absence of light, algae utilise oxygen. Although respiration also occurs in the presence of sunlight, the amount of oxygen released usually exceeds the amount used during daylight.
OIL YIELDS OF VARIOUS PLANTS
CROPS OIL IN LITERS PER HECTARE Castor 1,413 Sunflower 952 Safflower 779 Palm 5,950 Soya 446 Coconut 2,689 Algae 100,000
BIO-DIESEL FROM ALGAL OIL
The major problem associated with the use of pure vegetable oils as well as oil from algae as fuels for diesel engines is high fuel viscosity in compression ignition. Algal oil, as well as vegetable oils, is all highly viscous with viscosities ranging 20 times of diesel.
Castor oil has a viscosity 100 times of diesel Transesterification is however used to make vegetable oil useful for powering heavy-duty vehicles.
Theoretically, bio-diesel produced from algae appears to be the only feasible solution today for replacing petro-diesel completely. No other feedstock has the oil yield as high as that of algae.
It has been calculated that in order for a crop such as soybean or palm to yield enough oil capable of replacing petro-diesel completely a very large percentage of farmlands would be required. For algae, which has high yields per acre, to do so, the cultivation areas need not to be quite big. In practice, bio-diesel has not yet been produced on a wide scale from algae. Large scale algae cultivation and bio-diesel production will be likely in the near future (4-5 years).
ALGAE BIO-DIESEL ADVANTAGES
* Higher yield and hence lower cost
* Algae can grow practically in every place where there is enough sunshine
* The bio-diesel production from algae also has the beneficial by-product of reducing carbon emissions from power plants.
Algae is in fact one of the best sources of bio-diesel. It is very simple to extract oil from algae. Microalgae can provide several different types of renewable bio-fuels. These include methane produced by anaerobic digestion of the algal biomass bio-diesel. The idea of using microalgae as a source of fuel is not new but it is now being taken seriously because of the escalating price of petroleum and, more significantly, the emerging concern about global warming that is associated with burning fossil fuels.
The major disadvantage of using petroleum-based fuels is atmospheric pollution created by the use of petroleum diesel. Petroleum diesel combustion is a major source of greenhouse gas (GHG). Apart from these emissions, petroleum diesel is also a major source of air contaminants including nitrogen (N), sulphur (S), carbon monoxide (CO), particulate matter (PM) and volatile organic compounds (VOC).
Bio-diesel emissions are much more environmentally friendly than those of diesel fuel derived from petroleum. Data and test information available from Europe indicate that bio-diesel easily meets the 1993 European Economic Community (EEC) emissions established for diesel engines.
Sulphur is an emission from fossil fuels that contributes to destruction of the ozone layer.
BIO-DIESEL PRODUCTION IN THE EU (000 TONNES)
COUNTRIES 2002 2003 2004 2005 2006 2007 2008 2009 Germany 450 715 1,035 1,669 2,662 2,890 2,819 5,200 France 366 357 348 492 743 872 1,815 2,505 Italy 210 273 320 396 447 363 595 1,910 Austria 25 32 57 85 123 267 213 707 Spain --- 6 13 73 99 168 207 3,656 Denmark 10 41 70 71 80 85 231 140 UK 3 9 9 51 192 150 192 609 Sweden 1 1 1 1 13 63 With Denmark 212 Czech --- --- 60 133 107 61 104 325 Slovakia --- --- 15 78 82 46 146 247 Lithuania --- --- 5 7 10 26 66 147 Poland --- --- --- 100 116 80 275 580 Slovenia --- --- --- 8 11 11 9 100 Estonia --- --- --- 7 1 0 0 135 Latvia --- --- --- 5 7 9 30 136 Greece --- --- --- 3 42 100 107 715 Malta --- --- --- 2 2 1 1 8 Belgium --- --- --- 1 25 166 277 705 Cyprus --- --- --- 1 1 1 9 20 Portugal --- --- --- 1 91 175 268 468 The Netherlands --- --- --- --- 18 85 101 1,036 Romania --- --- --- --- 10 36 65 307 Bulgaria --- --- --- --- 4 9 11 435 Ireland --- --- --- --- 4 3 24 80 Finland --- --- --- --- --- 39 85 340 Hungary --- --- --- --- --- 7 105 186 Total 1,065 1,434 1,933 3,184 4,890 5,713 7,755 20,909
Oil extraction from algae is a hotly debated topic currently because this process is one of the more costly processes which can determine the sustainability of algae-based bio-diesel or bio-fuels.
In terms of the concept, the idea is quite simple: Extract the algae from its growth medium (using an appropriate separation process), and use the wet algae to extract the oil. The algae need not be dried before oil extraction.
There are three well-known methods to extract the oil from oilseeds, and these methods should apply equally well for algae too:
2. Hexane solvent oil extraction
3. Supercritical fluid extraction
There is a need of setting up 'Bio-fuel Research Center' in Pakistan to develop the bio-fuel industry that can better solve the current energy crisis. Scarcity of such plants may also be dangerous as they are the primary produces and their scarcity may create misbalance in the aquatic food chain. Thus, for a balanced ecosystem, a balanced population of the Algal Flora is necessary.