Developing cementitious buoys for ocean-based carbon dioxide removal

Abstract

In response to increased levels of carbon dioxide, which has led to a 1.5°C increase in Earth's average temperature, this master's thesis explores an innovative carbon sequestration solution. The oceans play a key role in sequestering carbon dioxide. They participate in both fast and slow carbon cycles, with the latter storing carbon at the ocean's depths. This research introduces a novel approach by developing cement-based and wood-based buoys, adorned with macroalgae, for deployment off the Icelandic coast. These buoys are designed to sequester carbon dioxide, enhance oxygen production, and integrate wood-derived carbon into the ocean's slow carbon cycle, thereby potentially mitigating climate change effects on ocean acidity.The goal of the research is to develop a solution for large-scale application. Therefore, the focus is on scalability and easy handling of the buoys. The buoys use easily available Icelandic raw materials, and they can float for at least three months to allow macroalgae to grow on them. Prototypes implemented in the project exceeded six months of buoyancy. To investigate how production could be scaled up, a paver production line was used - to simulate potential mass production. The study highlights the need to further investigate the effects of these buoys on sea acidity and the spread of macroalgae.The project not only presents a tangible and scalable solution to carbon sequestration, but also contributes to a broader understanding of ocean-based mechanisms to mitigate climate change.