A team from Algenol and Georgia tech has calculated the life cycle energy and green house gas emission with regard to ethanol production from algae. Algenol, which has been working on the direct to ethanol technology, performed a life cycle analysis (LCA) on the whole process of making Algenol’s ethanol. The results were published as an open access paper in the ACS journal, Environmental Science & Technology.
The analysis was done in order to prove the efficiency of the algae-ethanol over the fossil fuels. Direct to ethanol technology is based on an intracellular photosynthetic process in cyanobacteria (blue-green algae) that produces ethanol that is excreted through the cell walls, collected from closed photobioreactors as a dilute ethanol-in-water solution, and purified to fuel grade ethanol.
The life cycle analysis proved that the direct to ethanol technology can provide a 67% to 87% reduction in carbon footprint on an energy equivalent basis for initial ethanol concentrations.
It envisioned cyanobacteria grown in flexible-film, polyethylene-based photobioreactors containing seawater or brackish water as the culture medium.
To provide sufficient carbon dioxide to support efficient algal growth, the production facility is located near a fossil-fuel power plant or industrial source of carbon dioxide. The study’s calculation was based on use of industrial CO2, such as the byproduct CO2 from ethylene oxide production.
This reduction achieved is significant. But efficient green fuels are only meant for combustion engines. The study has not mentioned anything regarding CO2 emissions from electricity used in electric vehicles.
The electric cars are more efficient, and if electricity generation can more efficiently capture renewable energy sources than growing algae, the focus must be on developing these technologies.
Algae biofuel has a solar energy conversion efficiency of a few percents, and then a lot more energy is wasted in the internal combustion engine. Fast production of algae biofuels can help bridge the transition to fully electric vehicles.