I think most of us would rather live next to an oil well than the algae pond that will produce anything close to the equivalent. YMMV...
One plus is that they could be put out in the boonies, on poor land not worth farming. The water cannot be open to the air, however, or else other strains of algae would contaminate it.
Years ago, they set up wide clear laminate tubes to carry the water and algae at MIT, and even in the weak light of Massachusetts, and just bubbling with CO2, not NOx, the algae grew at a tremendous clip.
In the southern US, the biggest problem would be to keep the water from getting too warm, so they would need to set up cooling towers.