by Sharad Gupta, VP – Solar Design and Engineering at Oorjan Cleantech
By 2050, two-thirds of the population (around 6 billion) will live in the cities. Solar and wind energy are touted to play the main role in fulfilling these energy needs. But besides them, another source of energy, for a long time was touted to be a frontrunner in energy transition, but now has kind of lost its initial charm, is biofuels made from algae.
Ocean algae are the unsung environmental heroes. Algaes absorb about one-quarter to a third of the carbon dioxide emissions we emit. Through photosynthesis, they produce up to 50 percent of global oxygen. They mainly require two things- carbon dioxide and sunlight. But they also can be man-made, grown in laboratories.
Algae slowly found its way into the energy industry. To make biofuels out of them, first, algae are sourced from the ocean, or harvested in laboratories. After sourcing them they are dried, and ground into powder form, and then oil is extracted from it. The culture vessel used to grow such algae cultures is called a photobioreactor.
Algae produces 40 times more oil per acre than any other biofuel. And they have a harvesting cycle of 2 to 4 weeks. Companies like Chevron and Shell, for more than a decade, have been actively looking for zero-carbon alternatives. They had initiated algal biofuel programs but had to shut them down. What could be the reason? Despite the promising upsides, why aren’t we seeing more of it in our day-to-day lives?
This field of research is called bioprospecting and is extremely time-consuming and costly. Biomass harvesting is also a very water-intensive and nutrient-demanding process.
A measure suitable to understand the biggest drawback of algal harvesting is something called the EROI. Energy return on investment (EROI) is a sustainability measure to understand whether generating makes sense economically. If EROI is less than 1, the energy used in the production is less than the energy created. For algal biofuels, the figure stands around 0.13 to 0.71.
Additionally, the energy cost of extracting oil from algae biomass is 10 times higher than the energy cost of extracting from a biodiesel such as soybean oil.
It is a fairly new technology, and even though the research began more than 30 years ago, there hasn’t been enough funding thereafter.
Algae still is a relatively attractive proposition in the long term because of their high photosynthetic efficiency, the short-term prospects seem bleak due to the relatively high cost of cultivating algae. But inventing something is one thing, and commercializing something successfully is a different ball game altogether.
Still, we have made impressive progress in the last 10 years demonstrating the potential. The production and demand for fossil fuels aren’t stopping anytime soon. All the oil companies want to steer towards sustainability, but it’s hard to make money on such things, most money comes from oil.
The best way we can propagate the use of algae-based energy is for the producers to focus on manufacturing higher-value non-fuel byproducts that can be sold and profitable today. These co-products will help in reducing the net cost of producing algae biofuels. And centre our attention on minimizing the energy, water, and nutrients required and land use.
