Algae: From Generating Energy to Capturing Carbon

The race to lower human-induced atmospheric emissions has led to a slew of research into new technologies such as carbon capture and alternative energy generation. One area of study within this overarching incentive lies within utilizing naturally occurring solutions.

Since the earth's beginnings around 4.5 billion years ago, its many lifeforms have gone through varying threats. This has ultimately resulted in the survival of the fittest and the natural process of adaptation, such as can be seen with algae.

"Algae are microscopic organisms that live in aquatic environments and use photosynthesis to produce energy from sunlight, just like plants."

This organism poses an opportunity for alternative energy generation because all "algae have the capacity to produce energy-rich oils, and a number of microalgal species have been found to naturally accumulate high oil levels in total dry biomass." Further, algae can produce this biomass quickly, "with some species doubling in as few as 6 h, and many exhibiting two doublings per day."

Using Algae to Produce Energy

Biofuel is a fuel comprised of various biomass, the most common being ethanol and biodiesel. The former is sourced from plant materials such as corn, and the latter is sourced from vegetable and animal fats. Biofuel is generally regarded as a lower-emissions alternative to fossil fuel production. However, its environmental footprint can vary greatly depending on given factors.

For example, in some cases, mass-producing corn to create tons of ethanol can result in a carbon debt, meaning that more emissions are released during production than what is made up during the use stage.

This is because of the large number of resources needed to grow corn. That said, this information is relatively well known throughout the biofuel industry, meaning that many researchers have notably taken mitigative steps to prevent this event from occurring.

In comes algae, which provides a remarkable opportunity to help remedy these discrepancies while providing an eco-friendly energy alternative.

This type of biofuel has been shown to have a reduced environmental impact compared to many other biomass sources, namely those of terrestrial origin.

Additionally, because algae are prevalent throughout marine ecosystems, they pose less of a threat to contaminating waste streams and reduce the need for as much land use that, for example, corn would require. Algae also come in millions of varying types, meaning that scientists have a seemingly endless array of options to study from and utilize.

Nevertheless, as with most things, biofuels from algae pose some challenges. For example, even though their marine ecosystem prevents the need for as much land use, farming algae may still require a certain acreage to produce enough fuel to keep up with the United State's requirements.

Plus, this acreage would need water to create a habitat conducive to algae life, resulting in importing water into a given location if the desired habitat cannot be located as is. Other challenges that this biofuel faces include nutrients, crop protection, and cost.

Regardless, these discrepancies could be remedied with time, funding, and continued research. Until then, algae biofuel still possesses great potential for energy generation. And, coupled with other alternative energies, it could significantly help the United States and many other countries shift away from fossil fuel dependency.

This brings us to the other beneficial use of algae and, more specifically, algal blooms.

Capturing Carbon Thanks to Rampant Expansion

Algal blooms occur when algae grow excessively, at which point they then become "visible to the naked eye and can be green, blue-green, red, or brown, depending on the type of algae."

Brilliant Planet, a South African company founded in 2013, has set out to use algal blooms to capture carbon by the gigaton.

The company captures carbon by using the naturally occurring sequestration of algal blooms; only they scale it up.

Algae naturally remove carbon from the atmosphere through a process called carbon fixation, which means the carbon is essentially sequestered and, using photosynthesis, converted into oxygen and biomass. Some studies even have found that algae are responsible for 40% of the world's carbon fixation. By applying this knowledge to large algal blooms, Brilliant Planet could hypothetically capture significant carbon emissions.

To scale up, the company has created large algal ponds that utilize solar energy to circulate and pump seawater.

"In the process we do, we de-acidify that ocean water. So for every one unit of ocean water we bring in, we de-acidify the equivalent of five units of ocean water back to pre-industrial levels," explains Adam Taylor, CEO of Brilliant Planet.

"We have to move very large volumes of seawater around [the pond], and that uses energy, but we've done a lot of design work around running the system extremely energy efficient."

"So gravity feeds down through most of the system from one pond into the next. We have a partnership with Southampton University on optimizing every aspect of the paddle wheels and the ponds. A lot of time and effort has gone into minimizing that energy cost."

Though incredibly promising, algal blooms do have the potential to impact the environment and even humans depending on varying factors, typically referred to as harmful algal blooms (HABs). Despite this, Brilliant Planet has stated on their website that they are leveraging technology to help cater to the needs of the algae. This means that it will most likely help prevent the blooms from becoming harmful, primarily since they will be located in enclosed ponds.

Brilliant Planet's end goal is to get the cost of carbon capture to below $50 per ton, which could greatly assist its availability and, therefore, global warming remediation.