Enhanced Geothermal Systems (EGS) - CCUS Terms

Description:
Enhanced Geothermal Systems (EGS) are engineered geothermal reservoirs created by fracturing hot rock formations to enhance the extraction of geothermal energy. EGS involves injecting water into the hot rock, allowing it to absorb heat, and then extracting the heated water to generate electricity or for direct use in heating applications.

Explanation:
In the context of Carbon Capture, Utilization, and Storage (CCUS), Enhanced Geothermal Systems (EGS) play a complementary role by providing a renewable energy source that can help offset the carbon footprint of energy-intensive CCUS processes. Here’s how EGS works and its importance within the broader CCUS framework:

• Carbon Capture. While EGS primarily focuses on geothermal energy extraction, it can indirectly support carbon capture efforts. For example, the development of EGS can reduce reliance on fossil fuels for electricity generation, thereby lowering overall CO2 emissions from the energy sector. This reduction in emissions complements the goals of carbon capture technologies by contributing to overall emission reduction targets.
• Utilization. EGS can be directly linked with CO2 utilization processes. One potential synergy between EGS and CCUS is the use of captured CO2 as the working fluid in EGS operations. Instead of water, CO2 can be injected into geothermal reservoirs to enhance heat extraction. This not only utilizes captured CO2 but also improves the efficiency of geothermal energy production. The CO2 circulates through the hot rock, heats up, and is brought back to the surface, where the heat is extracted for energy generation before the CO2 is re-injected or utilized further.
• Storage. EGS can also play a role in the geological storage of CO2. The fractured and permeable rock formations created by EGS operations can serve as potential sites for CO2 sequestration. After the initial energy extraction phase, these formations can be repurposed for long-term CO2 storage, ensuring that the captured CO2 is securely and permanently sequestered underground. This dual-use approach enhances the economic viability of both geothermal energy production and CO2 storage.

Advantages:
EGS offers several advantages within the CCUS framework. It provides a sustainable and renewable source of energy that can significantly reduce CO2 emissions from the power sector. By utilizing captured CO2 as a working fluid, EGS can enhance geothermal energy production efficiency and create an additional use for captured CO2. The potential for dual-use of EGS sites for both energy extraction and CO2 storage can improve the economic feasibility of geothermal projects and provide a long-term solution for CO2 sequestration.

Challenges:
Despite its potential, EGS faces several challenges. The technology requires significant upfront investment and advanced engineering to create and manage the subsurface fractures necessary for effective heat extraction. Ensuring the long-term stability and permeability of the geothermal reservoir is crucial for sustained energy production. Additionally, the integration of CO2 as a working fluid in EGS operations requires further research and development to optimize the process and ensure environmental safety. Regulatory frameworks and public acceptance are also important considerations for the successful implementation of EGS projects.

In summary, Enhanced Geothermal Systems (EGS) are essential for promoting the development and deployment of Carbon Capture, Utilization, and Storage technologies. By providing a renewable energy source, EGS supports significant reductions in greenhouse gas emissions and contributes to global efforts to mitigate climate change.