Bioenergy is a renewable energy source derived from natural sources that can be used to replace fossil fuels. It has the potential to supercharge renewable electricity and generate a carbon sink when paired with geothermal.
Karan Titus, a UC Engineering Ph.D. student, has demonstrated that combining geothermal and bioenergy facilities may remove one million tonnes of CO2 per year.
The project is currently in its early phases. It might be a hopeful move, according to Titus, as the world's economies continue to pursue massive decarbonization initiatives.
“Finding new ways to minimize, or even reverse, emissions from geothermal energy sources can help Aotearoa New Zealand decarbonize its electricity sector by 2050 and reach a net-zero emissions economy by 2050, as set out in the 2019 Zero Carbon Act.” says his doctoral co-supervisor, UC Civil and Natural Resources Engineering Senior Lecturer Dr. David Dempsey.
This research focuses on an interesting technique for collecting CO2 from the atmosphere and storing it underground, as well as minimizing CO2 emissions from geothermal. As the technique is known, carbon sequestration is a fundamental component of most international climate agreements.
Traditional carbon sequestration remains difficult. The tens of millions of dollars required for deep injection wells, and the buoyant gas tries to escape higher.
Titus stated, “Geothermal systems solve both these problems. The wells have already been drilled, and we can dissolve CO2 into water that has to be reinjected anyway. This new approach is already being trialed in Iceland, another country with significant geothermal resources.”
Titus has looked into a new method known as Geothermal-BECCS (Bioenergy and Carbon Capture and Sequestration), which involves burning forestry debris to generate electricity. CO2 from the atmosphere is captured and injected underground. Bioenergy and geothermal energy can work together to produce more electricity than geothermal energy alone.
“Karan’s work targets some key issues for Aotearoa’s future energy system. Providing a reliable pathway for electricity generation that has net-negative emissions is very powerful and sets a great example for the rest of the world,” UC Civil Systems Engineering Lecturer Dr. Rebecca Peer, Titus' co-supervisor, said.