Urban Canopy: Using Artificial Photosynthesis to Sustainably Produce Butanol & Hexanol
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A world where fossil fuels are replaced by clean, sustainable biofuels… Urban Canopy is innovating a solution to make that world a reality.
There Is 104.8 ppm(parts per million) Too Much Carbon Dioxide In Our Atmosphere
For decades, one thing has become abundantly clear — the world is warming up, and it is ultimately proving to be detrimental. Sea levels are rising, eradicating coastlines. Ocean pH levels are rising, causing sea life to die. Winters are short, summers are hotter. Water becomes scarcer and scarcer as droughts become more and more frequent. By 2050, heatwaves could last for a month within America, and it might become so hot some days that it’ll be dangerous to go outside.
Global warming is caused when too many greenhouse gases are emitted into the atmosphere. One of these gasses, and perhaps the most impactful in regards to global warming, is carbon dioxide (CO2).
There are two components to solving the problem of excess carbon dioxide emissions: a) we must stop emitting carbon dioxide into the atmosphere, and b), we must sequester the excess carbon dioxide from the atmosphere in order to reach a safe and healthy amount of carbon dioxide present in the atmosphere, which is around 350 ppm.
****One of the main contributors to carbon dioxide in the atmosphere is the burning of fossil fuels, which contributes to 75% of all carbon dioxide emissions. Currently, there are undertakings to reduce the amount of carbon dioxide emitted. Notable attempts to steer away from fossil fuels include wind power and hydropower.
Another alternative to fossil fuels is biofuels such as Butanol and Hexanol. Such biofuels can be used to make a variety of substances and uses. Currently, Butanol can be used as fuel for cars without any needed engine modifications. In fact, Butanol contains 30% more energy per gallon than ethanol. It is also commonly used in the production of acrylic paint. Hexanol, on the other hand, can be used as a flavoring additive, insecticide, and as an ingredient in perfumes.
Biofuel is generally made by inducing fermentation, heating, and other chemical reactions on plant products and biomass, which will break down the sugars, starches, and other molecules. The resulting products can be used as fuel. However, obtaining this biomass is generally very detrimental to the environment. It requires an extensive amount of plant material, which takes away food from the environment and contributes to deforestation. Another issue is that it requires a lot of water. Finally, current processes release dangerous chemicals into the atmosphere.
The best way to create biofuels would to be develop a way to synthesize butanol without having to cut down trees and obtain biomass in traditional methods.
We Can Produce Butanol & Hexanol In A Carbon Dioxide Negative Way
Our solution is carbon dioxide negative, as our procedure will take in carbon dioxide, water, and electricity (obtained from solar panels), and produce butanol and hexanol. This technology uses electrolysis and fermentation in order to turn the CO2 and H2O into Butanol and Hexanol. Here’s how it works:
First, we capture carbon dioxide from the atmosphere. Scrubbing out 44 grams of CO2, also known as one mol of carbon dioxide, requires at least 56,000 liters of air. Simultaneously, photovoltaic cells (solar panels) receive sunlight which they convert into electricity. We will be using these solar panels not only to power the electrolysis of molecules, which is explained below but also to power the entire facility, making it a truly carbon dioxide-negative solution.
Next, in the electrolysis tank, electrolysis is induced by charging a silver-based cathode, which is the negatively charged electrode by which electrons enter an electrical device. Doing so will reduce the CO2 to CO, which is a syngas, or synthetic gas. We also charge an iridium-oxide-coated-titanium anode which oxidizes the H2O to O2.
The syngas produced by the CO2 electrolyzer is converted to acetate and ethanol by Clostridium autoethanogenum (an anaerobic bacteria). The butyrate and hexanoate are reduced by CO and H2 to butanol and hexanol by Clostridium autoethanogenum
Just like that, we’ve created butanol and hexanol and sequestered CO2.
We Have 2 Major Barriers, Which Can Be Overcome With Time
The biggest barrier facing this is material efficiency. Currently, the exact amount of butanol a machine can make/carbon dioxide it can take in is not a whole lot. However, this can be solved by using higher quality materials. Although they do not exist yet, current technological innovation will ensure that such materials will be available by 2025.
Another major issue is that carbon capture is not as efficient as it could be, since scrubbing out one mol of CO2 (44g) requires at least 56,000 liters of air. This also falls under a material efficiency issue. As with butanol-production efficiency, we estimate that this problem will solve itself as technology continues its everlasting march.
Deployment/Usability, Expansion, and Impact.
Our solution is not easy to deploy. Aside from the monetary cost of the solution, one tricky element of deploying our solution is finding the right locale. Ideally, we need lots of rain but also enough sun. Tropical areas are most suited to our needs. However, building our solution next to a coastline will eliminate the need for rain, so sunny areas next to water are also acceptable. Once a location has been targeted, we will contract a facility containing the necessary units needed for our solution to work. Our solution will not directly be sold to other companies. Instead, we will synthesize butanol and hexanol on our own, and sell them to those who would wish to purchase them.
Eventually, banking on the success of our initial location, we would need to expand. Whether we decide to make new factories in a new target locale or simply add capacity to existing factories is a consideration. However, we would ideally be adding nine factories worth of output within 5 years of our first factory creating profit.
The Driving Vision — About our Company
Urban Canopy will have created enough biofuels in a sustainable manner to rival fossil fuels, creating a brand new default-energy-supply, and limiting future carbon dioxide emissions drastically.
Our team envisions a world that does not emit dangerous levels of carbon dioxide. The dream of waking up, looking outside, and breathing fresh, unpolluted air is incredibly appealing, in part because many of our team have experienced the effects of global warming firsthand. We hope that our vision can become more than just a vision — we hope that it can become reality.
Thank you,
The Urban Canopy Team
Sources
Learning from leaves: Going green with artificial photosynthesis
Shout-outs!
Huge thank you to our amazing mentors:
- Hayley Caddes
- Brandon Jennings
- Navid Nathoo
Disclaimer — This project is purely an exercise. Although all technology referenced is real, Urban Canopy is not a real company (yet, at least 😉).
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