Mining NREL’s Zero-Emissions Fuels of the Future

Turning algae and other feedstocks like municipal solid waste (msw) into biofuels hinges on improvements in how the biomass is grown, collected, and processed. The National Renewable Energy Laboratory (NREL) is helping unlock the full potential of the U.S. feedstock supply after receiving over $2 million from the U.S. Department of Energy Bioenergy Technologies Office (BETO). Being used for two projects, the funding will support NREL scientists learn the best way to grow photosynthetic algae and also how to efficiently sort msw, important steps for making both feedstocks more economical.

Making biofuel from algae presents logistical challenges. Farmers must expertly grow algae in large outdoor ponds where the organisms are exposed to a range of weather conditions. The algal biomass must then be harvested and processed to generate the fuel-feedstock.

Cultivating Algae Using Air Captured CO₂

Scientists are increasingly interested in using photosynthetic microalgae to capture and store CO₂ from the atmosphere. However, today’s algae farms must be supplemented with cheap, steady streams of CO₂ — often from nearby powerplants or fuel refineries — and delivered so far in excess of algae ponds’ capacity that efficiencies are often less than 20%.

The NREL scientists’ objective is to improve the capture and storage efficiency of CO₂ by coupling algae cultivation as photosynthetic and biocatalysis systems to a mechanical tree harboring a passive direct air capture unit.

In concert with techno-economic and life-cycle analysis, the team, led by Lieve Laurens, will study the diet of a highly productive algae species to understand how it might be engineered to better store the greenhouse gas as cell biomass. They will also develop novel CO₂ delivery approaches in combination with the introduction of a highly effective carbonic anhydrase protein.

Other major participants in this research include Arizona State University and Silicon Kingdom Holdings.