The big questionis the energy cost of production.
For example, if it takes more BTU/watts. joules or whatever measure you wish to produce the consumer product, then it is a farce.
For example, it costs about 10% of a barrel of oil to produce consumer products-the 10% goes to electricity, heat, etc used from well to point of sale and the output is approx 90% useful products ranging from asphalt to gasoline and oils etc.
These “green” ideas are usually (if not always) more costly to produce than the energy they provide....
One of our algae researchers has made diesel fuel from fatty acid bearing algae-only problem is it costs about $1000 per gallon to produce, and to just manufacture enough bio-diesel to run the MODOT truck fleet, it would take every acre-foot of impounded water in the state of MO converted into algae ponds..... Realistic? NOT.
It all depends on how much the input BTUs cost and how much you can get for finished product BTUs
If you can start with cheap BTUs, waste stream wood, agricultural residue, etc, and process them in a cost effective manner to an expensive form of BTUs, such as gasoline, there is no reason you can’t make a buck.
I can turn something that has no inherent value, grass clippings, into something of value by letting it grow taller and processing it into convenient bales that my neighbors can use and are willing to pay for. This is not that different.
Algae has been a false promise from the beginning. Nobody ever had a strain they could keep alive and grow economically in a commercial operation. We have a current stream of cellulose, much of it waste in our current economy, if somebody can make it more valuable at a profit, they have the recipe for a business.