Mad about Science: Carbon neutral fuel

By Brenden Bobby
Reader Columnist

Matter can be neither created nor destroyed. So what happens when you pour $100 worth of fuel into your car’s tank, only for it to be empty in a week and a half? Where did it go?

Using up fuel in your car isn’t just deleting it from existence. The process of an internal combustion engine utilizes energy generated from applying heat to a volatile chemical (gasoline or diesel) to trigger a reaction that will split the fuel into its baser components, creating energy for the moving parts of your engine in the process. That energy transfer is then directed throughout the vehicle to make it move.

The baser chemicals are generally light enough to go from liquid to gaseous form and become a part of the atmosphere. There are an estimated 1.5 billion vehicles in the world, leading to a lot of waste products in the atmosphere.

Atmospheric carbon has a powerful insulating effect called the greenhouse effect. Essentially, carbon lets light in, but it doesn’t like to let heat back out after the light has impacted a surface and produced heat energy. The closest approximation is the acrylic panels of a greenhouse, which allow light in and trap heat inside, hence the term “greenhouse effect.”

It’s undeniable that we need energy sources to power our daily lives — especially in rural North Idaho — so the idea of saying, “Forget fossil fuels,” is kind of absurd, to say the least. These are things we need to thrive in our modern world, but there are steps that we can take to mitigate the damage we do to our environment.

Synthetic fuels can and have been created to help mitigate climate change, though these fuel sources aren’t a panacea for all climate and energy woes. One of these applications actually requires the environment to have been already altered in order to create the fuel.

The Navy is currently working to deploy processes to create synthetic jet fuel from carbonic acid pulled from the ocean. This requires an energy source that fossil fuels would typically fill. Nimitz class aircraft carriers are equipped with nuclear reactors to keep them powered, and would allow for them to harvest carbon from carbonic acid in seawater. Carbonic acid mostly comes from carbon in the atmosphere as a byproduct of internal combustion engines. The ocean absorbs CO2 from the atmosphere, and the CO2 merges with water to create carbonic acid.

A surplus of carbonic acid has a detrimental effect on the ocean at large by harming fragile organisms such as shellfish and coral, which creates a cascading effect throughout the oceanic ecosystem. Being able to “scrub” seawater and pull fuel from it without adding more waste products to the atmosphere helps mitigate some of the damage done by motorized vehicles, especially in times of peace.

Due to the highly controlled nature of nuclear energy, this solution can’t be widely applied to most ships. However, every little bit helps, and if this turns out to be a profitable endeavor, it could well be applied to specialized ships in the private sector, similar to how plastic collectors have been deployed over the past couple of years.

Microalgae is another form of potentially carbon-neutral fuel. Unlike things like fossil fuels, microalgae lends itself to a huge variety of organic purposes including pharmaceuticals and livestock feed. Crude oil pumped from the ground is the fossilized remains of ancient algal mats, so it’s only logical to explore the utilization of algae as a form of modern fuel.

The premise of how algae can become fuel is relatively simple, even when the extraction process is dense. Essentially, algae is a very basic form of plant life that draws in carbon dioxide and, through photosynthesis, cleaves the molecule into O2 and carbon, spitting out the oxygen as a waste product and keeping the carbon as building blocks to create more algae. We are then able to harvest the carbon as an energy source, applying heat and forcing it to bind with O2 and creating energy in the process.

Algae is extremely efficient at storing carbon compared to most other plant life. It’s also resilient and capable of thriving in a huge variety of environments so long as it has adequate moving water. Under the proper conditions, it can even be stored for hundreds of millions of years either as a carbon sink or a future fuel source, as is the case with oil.

Algae have been responsible for massive climate shifts in the Earth’s distant past. Over 2 billion years ago, a massive surge of cyanobacteria caused the greatest mass extinction the Earth has ever seen. Blue-green algae spread in huge quantities all over the world, absorbing an immense amount of carbon dioxide and spitting out O2 as waste. This completely altered Earth’s atmosphere, changed the planet’s average temperature and laid the foundation for life as we know it to exist on planet Earth. Oxygen was poisonous to most organisms alive at this time, and the rapid growth of O2 in the atmosphere killed most life on the planet with the exception of the cyanobacteria.

Plants are metal, man.

Unfortunately, using algae as fuel will never be a carbon-negative solution as it will always return carbon dioxide to the atmosphere.

Stay curious, 7B.