What the man said is true, except that the carbon dioxide the algae has sequestered will come back out when the fuel is burned. However, it is very miniscule compared to the carbon dioxide in fossil fuels such as coal and petroleum products.
Any organic matter can be converted to fuel if we use the correct chemical processes. Corn cobs release the most fuel and switchgrass the least (by this method). While, in between these two products we have pig fecese, chicken litter and many other 'waste' materials that are in abundance year around, and without affecting the food chain or the natural fertilizer.
I have put several years of research into converting chicken litter since we have Tyson and Perdue both producing chickens in our area (that's millions of chickens and each one produces 2 1/2 pounds of litter in a lifetime). The best estimate I can come up with is 3,000 gallons per chicken house per cycle (6 weeks).
All the chemical compound required is abundant in nature in our area and between those two companies and the other animal producers locations all around our great nation, we can at least keep the agri-economy going with this waste. The fertilizer is left over when the process is completed and the only carbon released is that which was sequestered by the corn in the field.
There is also a method of burning coal underground (no mining involved) seperating the fuel gas from the sulphur and carbon (which also have a readymade market) then liquefiy the gasses to diesel fuel. The Germans fueled their war machine on this type of diesel during WWII.
We have all we need to be energy independent, right at our fingertips. And it could happen this calender year if private industry is willing to invest and use it. Our government is not capable of solving our energy needs!