I think Algae bio diesel is the best alternative than corn,soybean,palm oil ,sugarcane,etc.but it's still in testing

It will become available once they manage to increase yield and decrease cost. Right now it is not profitable to produce it.

Algae appear to have advantages. Fine. I buy when available. But remember that before a technology is on the market, anything can happen, the most common result being "too expensive after all".

 

Another hurdle: taxes make most of Diesel oil's cost presently. Vegetable oils are already cheaper than Diesel oil (in Europe) because of lower taxes on food, so many governments hinder the use of vegetable oils. For an alternative to break through it should better be cheaper than Diesel oil prior to taxes, and that's damned hard.

At the moment, algae are produced in roughly 2 types of 'reactors'. There are the open pond systems, which have low productivity, but which are technically easy to build, require little energy but may need a lot of water (losses are due to evaporation). And there are the closed systems, often tubular reactors, in which the insanely high productivities are achieved that sound so promising. However, these tubular reactors require a LOT of energy, to get CO2 in, and O2 out of the water, and to keep the water turbulent enough to rotate the algae into and out of the sun quickly. And I haven't read much about the cooling of these tubular systems, but I can imagine that they can get really hot on a warm day in a desert, so that's another issue which will cause additional expenses.

 

The open pond systems just don't come near the promised high yields, and are therefore not that interesting (in my opinion). The closed systems are so expensive - both in terms of investment and operating costs - that they are not economical yet. When will they be economical? I think that it's safe to say that they won't be for another 5-10 years.

Anyone may grow algae in a pond, harvest it, dry it, and press it into pellets that can be burned in a pellet stove.