The experimental boat, intended for use in rivers and marshes and eventually destined for oil installations in the Middle East, operated on a 50/50 mix of algae-based fuel and diesel.

The navy plans to roll out its first green strike force, a group of about 10 ships, submarines and planes running on a mix of biofuels and nuclear power, in 2012, with deployment in the field scheduled for 2016.

The current cost of a gallon of algae-diesel mix is $424 a gallon.

The early versions of algae-based fuels had a short shelf life, with the fuel separating in the tank, sprouting, or even corroding engines. “They had some not very good characteristics at the end of the day,” he admitted.

But the navy appears committed. Last month it placed an order for 150,000 gallons of algae-based fuel from a San Francisco firm.

OK. So they purchased $64 million dollars worth of corrosive green algae which sprouts in the engine and needs to be supplemented with diesel and nuclear.