Fossil fuels are valuable for electricity generation, transportation energy, and plastics production. However, they are a finite resource. Algae-based biofuels have been proposed to reduce dependence on this limited resource; however, current algal growth methods are too costly to compete with the fossil fuels industry.
ISTC researchers are working to improve algal growth rates by growing algae in municipal wastewater combined with captured CO2 from coal-fired power plant flue gas. Algae require nutrients and carbon dioxide to grow. Municipal wastewater can feed algae because it contains high nutrient concentrations that must be removed before the water is sanitized and released. Traditional nutrient removal processes involve a series of biological and chemical methods. If nutrients are used to grow algae, the costs of removing them go down. In addition, algae growers do not need to purchase nutrient products to enhance algae growth.
Like other plants, algae use CO2 to convert sunlight into energy that the plant can use along with the nutrients to grow, a process called photosynthesis. Algae grow and can uptake CO2 faster than any other photosynthetic crop, giving them a lower environmental footprint than other crops. Therefore, feeding captured CO2 from coal-fired power plants into algal growth tanks can further boost growth rates. In addition, the captured CO2 will be used to create algae that can then be converted into a new energy product. Coal-fired power plants could potentially reduce their carbon emissions by using this method to utilize CO2. Furthermore, using these waste products (nutrients in wastewater and captured CO2) to grow algae could make algal biofuels cost-competitive with, or even cheaper than, fossil fuels.
This project is in collaboration with Helios-NRG, LLC and is funded by the Department of Energy. Results from this study are expected in Fall 2020.