[marcosdumay]

Hum... A large share of the solar costs are on support and installation. Those are proportional to the area, and are even higher (by area) for algae, because algae requires some water, and water is heavy.

So, if they need 20x the area, just their support and installation will already cost some 5x more than a full solar plant.

[LoveMortuus]

Also these algae need an open system so that they don't kul themselves. And I think they might be much more sensitive to heat and especially cold then solar panels.

Algae are living creatures just like humans and stuff, so keeping them alive is probably harder then with solar which is basically just nicely arranged rocks and crystals.