Summary
Algae fuel is a type of biofuel used as an alternative to liquid fossil fuels. Biofuel can be produced from plants or from agricultural, domestic or industrial biowaste with bioethanol and biodiesel the most common. Algae, both microalgae, and macroalgae, such as seaweed, turn inorganic compounds such as CO2 and water into complex, energy rich hydrocarbons using light. The creation of algae fuel involves growing microalgae in photobioreactors, breaking down the plants’ cell walls with a chemical solvent, extracting the lipids, proteins, and carbs, and processing the remaining oil into usable biofuel. Algae can be made into different fuels such as biodiesel, biogas, and jet fuel depending on the type of production and the part of the cells used.
Viability (2)
There is debate as to whether algae biofuels are viable at sufficient enough scales. Throughout the 1970s and the 2010s millions of dollars was poured into algae fuel with little to show for it. Almost all of the first and second waves of investment failed, with ExxonMobil and Viridos (formally Synthetic Genomics) are one of the few partnerships still in progress with efforts continuing to produce 10,000 barrels of algae biofuel per day by 2025 although little evidence of progress has been made public. There is skepticism that algae fuel production can scale up to large enough volumes considering the size of the growing pools and the amount of fertiliser and CO2 needed, even with genetic modification.
Drivers (4)
The need to replace liquid fossil fuels in the energy system has been the predominant driver of algae fuel research. In particular, the difficulty of decarbonising shipping and aviation has led to renewed interest in sustainable biofuels. Biofuel already contributes 3% of the world’s fuel for road transport, but it needs to rise to 25% by 2050 to meet the Paris Agreement goals. In April 2021, the US Department of Energy committed $61.4 million to new biofuel research primarily to help decarbonise aviation and shipping. On the supply-side, CRISPR has made bioprospecting cheaper and faster, enabling scientists to test and finess the best algae strains.
Novelty (2)
Algae fuel competes with liquid fossil fuels like oil and LNG, other biofuels, Green Hydrogen as well as other ways to decarbonise transportation such as electrification and batteries. Different decarbonisation technologies compete on price, performance and environmental impact. Algae, at large volumes, has theoretically one of the best performance measures as it is one of the most efficient organisms in the world as converting sunlight to oils, which should in term result in high yields and lower cost. But it’s a mixed picture on environment impact. It also doesn’t need cultivable land like corn or soya-derived biofuels, and can be grown almost anywhere including brownfield and waste land even in saltwater or wastewater. But requires much more water, fertiliser, and genetic modification than waste and residue-based biofuels.
Diffusion (2)
Aside from cost which will be the biggest barrier, algae needs significant water to be harvested, even if the water doesn’t have to be clean or fresh. It also needs a lot of fertilizer with some estimates in the range of 15% of annual fertilizer production to meet 5% of the U.S. transportation market. Another big restraint is the risk of growing genetically-modified algae in open-air systems which would be required to to produce oil in high volumes. The risk is that GM-algae could escape the systems, outcompete native species and cause harmful algae blooms. Even at a low-price point comparable with oil, the resource demands and environmental concerns will make it difficult to compete with waste and
Impact (1)
It’s hard to make a high impact case, even if algae fuel can be produced at scale with say green ammonia and environmental risks are mitigated. A future of Green Hydrogen for heavy transport combined with Direct Air Capture and Carbon Capture, Utilisation & Storage seems much more plausible considering the speed at which action needs to be taken and the rapid development of the green hydrogen supply chain.
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