Growing Algae for Biofuel

Algae can be grown for biofuel, in both photobioreactors and open ponds. Photobioreactors are completely controlled system, where all the growth factors such as light, CO2, temperature, Nutrients etc. are all artificially supplemented.

Algae are a very reliable renewable energy source. Naturally algae can grow in diverse but humid environmental conditions such as in open ponds with out any artificial care or treatment. But the bulk of algae biomass which is needed for biofuel production is very huge and growing of algae in open ponds can’t produce enough algae biofuel. Growing of algae in open ponds is more cost effective for food than for biofuel. The most preferable method of algae culture for biofuel is by using photobioreactors.

What are the requirements in photobioreactors for greater harvest? The requirements are-

• Water: could be either sea water or fresh water depending on the specific species of algae. For example micro algae requires fresh water and
• Carbon dioxide: Algae are consumes huge amount of CO2 so artificial injection of CO2 is must for higher yield of biofuel. Source of CO2 includes coal power plants or compressed CO2
• Optimum Temperature: also differ from species to species and the temperature range is 15 to 35 degree Celsius
• Nutrients: is applies in the form of fertilizers more or less similar with fertilizer applies to terrestrial crops. Nutrients including Nitrate, Phosphate, Iron etc
• Recycling of water: is useful to remove toxic or undesirable wastes which are produced by the algae
• Optimum level of stress: Under stress conditions algae produce higher amount of oils. Stress conditions can be created by reducing nutrient level, and moisture at the algaes' peak threshold.
•  Light: light is artificially provided for optimum and fast rate of growth. In the photobioreactors the light sources could be florescent lamps. But some times in some photobioreactors natural sun light can be utilized, but most algae species are very sensitive to strong direct sunlight therefore the intensity of the sunlight should be reduced by using either tinted glasses or netting systems.
• pH: Algae loves alkaline waters so by all means the pH of the water should be kept at 8; the water in the pond or in the photobioreactors should be recycled regularly to keep the water at pH 8.

Growing algae for food

Many species of algae such as Spirulina algae are very rich sources of food. They contain almost all the Proteins, Carbohydrates, Vitamins and Minerals. Some of the nutrition such as Omega-3 fatty acids presents only in algae other than fishes. Once produced they can be sold to food companies in bulk. But the quality (weather the algae is free from contaminants or not) will determine the price and marketability of the produced algae.

It is very easy and profitable to grow algae for food, if the growing conditions suitable for algae are mate. These conditions include nutrient filled water, sunlight (dim sunlight), additional source of carbon dioxide, suitable temperature, and suitable pH.

There are two major ways of growing algae, these are growing algae in photobioreactors and growing algae in open ponds. Growing algae in photobioreactors involve the growing of algae in enclosed transparent containers, which are called photobioreactors. And growing of algae in open ponds involves growing of algae with out any cover container in an open environment where the algae get direct sunlight. The two techniques of growing algae have their own advantages.

Advantages of Photobioreactors

• They give control on the system such as the amount of biomass produced, the amount of light, the amount of carbon dioxide and other gases, easy to regulate the temperature, easy control of the amount of nutrients in the water and easy control of the pH
• Relatively they have less contamination which comes from other weed or unwanted species of algae. For this reason alga grown for food in photobioreactors is considered high in quality.
• Algae grow and and mature at a faster rate
• There are no evaporation losses of moisture
• Produce expensive algae
• Algae can be produced at any environmental conditions since all the growth factors such as nutrients, temperature, sunlight, pH and amount of gases are artificially controlled.
• It has an advantage over open pond, for its quality, purity and higher price, but photobioreactors are very expensive to setup and to run.
• Photobioreactors require a small area for production, but they require a lot of building facility, which is very costly.

Advantages of Open pond

• Growing of algae in open ponds is very cheap
• It can be done in any open pond
• It can be done at home for extra income
• It doesn’t require any control Other than supplementing nutrients and artificial injection of CO2 and controlling the amount of direct sunlight by providing some shading mechanism.
• Cost effective to produce algae in such open ponds
• They require no building facility, but they need more area than photobioreactors.
• They are easy to set up, but they are very difficult to manage due to contamination and environmental fluctuations. Also evaporation losses of moisture is very high