Harnessing Microalgae for Low-Cost Carbon Capture and Utilization: A First Pilot Project Implementation in Indonesia’s Energy Industry Towards Net-Zero Emissions

Abstract This project aims to implement a low-cost, sustainable carbon capture utilization (CCU) technology using microalgae at Pertamina Donggi Matindok Field. The innovation supports the company’s commitment to achieving net-zero emissions and provides an alternative to costly CO2 injection methods, particularly for facilities with low CO2 emission rates. By harnessing microalgae's ability to process CO2 through photosynthesis and convert it into biomass, this approach seeks to reduce greenhouse gas emissions while simultaneously producing value-added products such as biofuels, animal feed, and fertilizers. The pilot-scale system captures CO2 from raw gas impurities, which are separated in the Acid Gas Removal Unit (AGRU), and processes it through biological conversion using Chlorella vulgaris microalgae. This species is selected for its high CO2 absorption efficiency and adaptability to industrial applications. The system integrates microalgae facilities—comprising contactors, reactors, and bag filters—into the existing infrastructure, where CO2 is absorbed, and biomass is harvested. Microalgae cultivation is optimized for maximum CO2 absorption, with the capability to absorb up to 1.83 kg of CO2 per kilogram of biomass. Operational parameters, including light intensity, CO2 concentration in water, and organic nutrient availability, were carefully controlled to ensure optimal growth and absorption efficiency. The pilot implementation achieved an annual CO2 emission reduction of 1,515 tons CO2eq, resulting in significant cost savings. The pilot system also produced 2.7 kg of biomass per year at a flow rate of 5×10‒4 MMSCFD. A scale-up to 0.15 MMSCFD is planned for execution in the following years, with the potential to absorb up to 2,800 tons of CO2 annually and produce 0.8 tons of biomass. This technology not only reduces the environmental impact of industrial emissions but also offers a cost-effective solution for low CO2 emission producers. Additionally, the biomass generated holds economic value as biofuel and animal feed, aligning with the principles of a circular economy. This project showcases the first industrial application of microalgae CCU technology in Indonesia Oil and Gas Industry, highlighting its potential as a cost-effective and environmentally friendly alternative to CO2 injection. The authors hope this method can be replicated in other facilities facing similar challenges, providing a scalable and practical solution for reducing industrial CO2 emissions.