In the heart of the Algerian desert, an innovative energy solution is brewing, one that could revolutionize how we think about depleted gas fields and carbon capture. A recent study published in Energy Geoscience, led by Amrou Al-Alawi from the Water Research Center at Sultan Qaboos University in Muscat, Oman, explores the potential of using depleted gas fields for both CO2 storage and geothermal energy harvesting. This approach, known as carbon capture, utilization, and storage (CCUS), is gaining traction as a means to combat climate change while generating clean energy.
The Toual gas field in Algeria serves as the backdrop for this cutting-edge research. Al-Alawi and his team have developed a three-phase operational scheme that leverages the existing infrastructure of the field to inject CO2, circulate it to harvest geothermal energy, and then extract hot CO2 for power generation. The process is designed to span over a century, with each phase lasting several decades.
The study presents three scenarios, each with varying degrees of economic feasibility. Scenario 1 utilizes the existing nine wells of the Toual field, while Scenario 2 optimizes the process by adding seven newly drilled wells. Scenario 3, however, assumes that all wells are newly drilled, providing a baseline for comparison.
The results are promising. Scenario 2, which combines existing and newly drilled wells, yields the best economic metrics, with a Levelized Cost of Energy (LCOE) of 0.97 USD/MWh and a Net Present Value (NPV) of $2.9 million. Both scenarios represent profitable endeavors, with Return on Investment (ROI) values of 1.3% and 1.5%, respectively. In contrast, Scenario 3, which does not leverage existing infrastructure, is economically infeasible, with a negative NPV and ROI.
“This study demonstrates the potential of integrating CO2 sequestration and geothermal energy harvesting in depleted hydrocarbon reservoirs,” Al-Alawi said. “The use of existing infrastructure is key to making this process economically viable.”
The implications of this research are significant. As the world seeks to reduce carbon emissions and transition to clean energy, the ability to repurpose depleted gas fields for CO2 storage and geothermal energy harvesting could be a game-changer. It offers a way to mitigate the environmental impact of fossil fuel extraction while generating clean, renewable energy.
Moreover, this approach could provide a new revenue stream for energy companies, extending the life of depleted fields and creating jobs in the process. It also aligns with the growing trend of circular economy principles in the energy sector, where waste is minimized, and resources are kept in use for as long as possible.
The study, published in Energy Geoscience, which translates to Energy Earth Science, provides a roadmap for future developments in the field. As Al-Alawi notes, “The next steps involve further optimizing the process, conducting pilot tests, and exploring other potential sites for this technology.”
The energy sector is at a crossroads, and innovative solutions like this one could pave the way for a more sustainable future. By unlocking the potential of depleted gas fields, we can turn a liability into an asset, creating a win-win situation for both the environment and the economy.