Biofuels are energy resources made from organic matter. Since fossil fuel burning is the top cause of air pollution, cleaner fuels are in development to transition world economies off finite fossil resources.
These developments are especially important for the aviation industry as electric airplanes are not be a near-future solution and more and more people are flying each year. It accounts for 5% of anthropogenic global pollution now and that number is projected to quadruple in a decade.
Second generation biofuels are currently the best means to transition away from fossil fuel. However, algal biofuel has important potential because it’s one of the few alternatives that can replace fossil resources at a large scale.
Algae as a Third Generation Biofuel
Third generation biofuel is centered on algal research but faces technical and economic barriers. Three different types of algae are currently researched as potential energy carriers: microalgae, macroalgae (seaweed), and cyanobacteria (blue-green algae).
Algae oil has a short harvesting cycle and can be ready for cultivation in days compared to the weeks second generation feedstock takes. Like second generation fuels, algae absorbs CO2 from the atmosphere for photosynthesis, leading to a reduction in greenhouse gases.
Algae can support a diversity of fuel types. It can be refined into diesel and gasoline and can be genetically modified to produce ethanol, butanol, and diesel directly.
Algae also requires much less space and doesn’t face issues of different land types. Because of this low land requirement there’s little land use conflict. Plus it promises higher energy yields than second generation biofuels.
Benefits of Green Products
Algae is harvested fast and with the right resources can produce up to 20,000 gallons of fuel per acre, an incredible amount of energy efficiency per surface area. This is the third generation biofuel’s most competitive attribute.
According to a Department of Energy study this means it could supply all US energy needs using only 0.42% of US land area.
Comparative energy yield table
Algae can be grown anywhere it’s warm enough. Depending on algae type there are three possible systems of cultivation:
Open ponds: Simple low-tech and low-cost ponds, however operators have little control over conditions and much water is lost through evaporation.
Closed loop systems: Closed systems which give growth operators greater control. Industrial waste gases from factories with higher levels of CO2 (up to 15% compared to atmospheric 0.36%) are channeled here to boost photosynthesis and cut carbon in the air.
Photobioreactors: Sophisticated closed systems which provide growth operators with greatest control over light, nutrient, and temperature levels.They are the highest cost and have the highest energy yield expectations.
Once harvested all water needs to be drained from algae so it becomes a dry powder. This is one of the most energy-intensive parts of the process. From there the algae’s cell structure is broken down into lipids or carbohydrates through extraction (pressing) or ultrasonic waves.
After this it goes through chemical, biochemical, or thermochemical processes to become the needed fuel type by extracting metabolites, or fatty acids, oils, or carotenoids.
Resource Requirement Challenges
One challenge development faces is algae requires large amounts of water and nutrients to photosynthesize fast enough for promised high energy yields.
Algae can be harvested in saline ponds, so it doesn’t compete with fresh water needed for agriculture. However, these nutrient requirements were both an environmental and commercial deterrent. Because of the high cost, many algae farmers turned to producing better quality smaller quantity harvests so, efforts to produce cleaner jet fuels to replace kerosene in aviation have been lessened.
Nitrogen and phosphorus are highly concentrated in runoff from chemical fertilizers and pose a big leakage problem in US waterways.
A 2011 study proposed wastewater-based cultivation since both nutrients are necessary for algae production. Using wastewater to grow algae would cut environmental pollution in waterways, creating clean water as a byproduct, and cut costs for algal farmers. A five month wastewater treatment study at Rice University in Houston demonstrated increased open tank algal production under these conditions.
The Houston study also found temperatures must be around 25-30 °C and stable for optimized algal metabolic and reproductive rates.
First Investment Efforts
Cost efficiency is the biggest hurdle to scaling algal cleaner fuel development.
Development is spoken about in a 2005-2012 bubble. During this time the US government and venture capitalists poured millions of dollars into this research and development for algal biofuels.
Green technology companies promised millions of gallons of algal biofuel but not even 1 million gallons has been hit. Because of these missed targets algal biofuels are not yet economically viable.
Few of these algal energy companies are left standing. Since 2017 the majority have pivoted to other more expensive algal-based products, like cosmetics and pharmaceuticals.
R&D investments are ongoing, like Synthetic Genomics in California and Reliance Industries in India. But many of them are funded by oil companies like ExxonMobil or Shell Oil, companies with little interest in pushing for algal biofuel to overtake fossil resources in the near-future.
Benefits of Algal Biofuel
Algae feedstock are the unique cleaner fuel with capacity to scale and power high energy needs without use of farmland. So, they could serve as a transitional solution away from fossil fuels and towards more viable alternative energy resource, like fourth generation biofuels.
Algal biofuels bring positive by-products like clean water and feed for animals.
Flightnook is optimistic because demand for non-fossil alternatives is increasing. We support algal and similar cleaner jet fuel producers by enabling flight-takers to pay the price difference to boost this development, which saves up to 80% CO2 on a life cycle assessment when compared to fossil fuels.
Only when biofuels are produced sustainably and reduce emissions, we can call them clean fuels. Join us to lessen your travel footprint and make cleaner flight a reality.
Fourth generation biofuels do not require destruction of biomatter and can be produced on non-arable land. Aviation “drop-in” fuels of this type include electrofuel and photobiological solar fuel.
We are ecstatic to see this development in Montréal with SAF+ Consortium, a fourth generation biofuel developer who is creating cleaner jet fuel from industrial CO2 emissions.
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