I'm really surprised that the BIG OIL companies haven't gone all-in on Bio-Diesel manufacturing....one of the bigger drawbacks of all petroleum fueled engines is the carbon dioxide emissions (the CO2 that is being released was locked up millions of years ago by the algae/plants, and then was turned into oil by time/pressure). BD eliminates that as the CO2 it releases when burned is recycled...you grow something (corn, green algae, whatever) which removes CO2 from the atmosphere), squish it and refine it to make the BD, burn it and it simply puts back the same carbon it took out of the air....so there is no NEW to this environment CO2 (which is pretty undisputed as a greenhouse gas speeding climate change...just think of how much oil is burned every day on the planet...that's a LOT of new CO2). Being as everybody agrees that the big diesel trucks (and ships/trains/planes, all using some variation of diesel) aren't going anywhere anytime soon...what would replace them?)...having BD available in large quantities would be HUGE in slowing greenhouse gas emissions world-wide. Considering that a diesel engine will burn pretty much ANY oil (it will even burn it's own engine oil if there is a blown head-gasket), BD just makes sense.
There have been tons of studies on Green Algae BD...anybody who has had an aquarium knows how easy it is to grow green algae. All you need is water, nutrients, and sun (keeping it simple, obviously there is a bit more to it)....I saw (on the internet) one site in a desert environment (ie, cheap land!) where they made these huge clear-vinyl hanging-radiator-type things...they just hang from a large post-setup, hook up water piping to the top and bottom, put a whole bunch of them on a single system (closed loop so the water isn't evaporating), supply a nutrient (algae isn't too picky...fish poop works fine), and circulate the water...bam...green algae grows...seperate the algae out, squish it for it's blob of oil, use the remains to power your system (burn it to make electricity to power the water pumps)...think of all the nearly useless land on the planet there is to do this! Just import your water, setup the hanging radiators (by the thousands or more), and start growing tons of green algae. Obviously there's more to it than that, but with the prices of gas/diesel lately, I'd think it could be money making item. Just think if most of the petroleum diesel could be replaced with BD on the planet, that would be HUGE....AND it would keep diesel engines alive for generations to come...just my 2 cents.