Subsurface Thermal Energy Storage Using Multi-Zone Geologic Formations
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Solution Overview
Problem
Current energy storage systems, particularly those above-ground, lack the capacity to address diurnal and seasonal supply/demand mismatches driven by variable renewable energy sources, and existing technologies for carbon capture and storage (CCUS) do not justify the costs, limiting the utilization of low-carbon energy sources.
Innovation Solution
The method involves using a geologic formation to store excess energy as thermal energy by heating brine to different temperature ranges, with multiple storage zones, and utilizing a system of wells and heat exchangers to manage and inject heated brine to maintain desired temperature ranges, along with huff/puff wells for supplemental non-aqueous fluids to enhance energy storage and production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If above-ground energy storage systems are used, then deployment flexibility is improved, but storage capacity is insufficient to address seasonal supply/demand mismatches
Solution Approach 1:
The patent transitions from above-ground energy storage to subsurface geologic formations, utilizing the third dimension (underground space) to achieve both high storage capacity and deployment flexibility. The system injects compressed CO2 and heated brine into permeable geologic formations, leveraging subsurface volume to store energy seasonally while maintaining flexibility through selection of suitable geologic sites.
2Productivity
If CO2 capture systems operate continuously to maximize low-carbon energy utilization, then energy production is optimized, but operating costs increase due to high energy consumption
Solution Approach 1:
The patent enables continuous operation of CO2 capture systems by integrating thermal energy storage that accumulates heat during periods of excess renewable energy generation. This stored thermal energy is then used to maintain CO2 capture system operation during periods when renewable energy is insufficient, allowing continuous low-carbon energy production without proportionally increased energy consumption.
Solution Approach 2:
The system utilizes parameter changes in thermal energy storage, heating brine to high temperatures (e.g., 200-400°C) during energy surplus periods and then utilizing this stored thermal energy during deficit periods. This parameter change allows the system to decouple CO2 capture operation from immediate energy availability, reducing overall energy consumption while maintaining continuous production.
3Loss of energy
If multiple storage zones with different temperature ranges are used, then thermal energy storage efficiency is improved, but system complexity increases
Solution Approach 1:
The patent divides the subsurface storage system into multiple zones with different temperature ranges (e.g., high-temperature zone for 200-400°C, medium-temperature zone for 100-200°C, and low-temperature zone for below 100°C). Each zone stores brine at appropriate temperatures, reducing thermal losses by preventing excessive heat dissipation. This segmentation improves thermal energy storage efficiency while the zones can be implemented using existing geologic formation layers, moderating the increase in system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient storage and retrieval of energy, optimizing the use of low-carbon energy sources, reducing CO2 emissions, and providing a cost-effective solution for CCUS by allowing continuous operation of CO2 capture systems and enhancing the utilization of renewable energy.
Implementation Method 1
store excess energy as thermal energy by heating brine to different temperature ranges
Implementation Method 2
utilizing a system of wells and heat exchangers to manage and inject heated brine
Implementation Method 3
storing energy, and in some instances excess energy, in permeable geologic formations using compressed non-aqueous fluids and pressurized heated aqueous fluids
Implementation Method 4
pressurized heated aqueous fluids
Implementation Method 5
huff/puff wells for supplemental non-aqueous fluids to enhance energy storage and production
Data Source
AI summary
The present disclosure relates to a method for storing excess energy from at least one energy producing source, as thermal energy, using an existing geologic formation. First and second storage zones formed in a geologic region may be used to store high temperature and medium high temperature brine. When excess energy is available from the energy producing source, a quantity of the medium high temperature brine is withdrawn and heated using the energy supplied by the energy source to form a first new quantity of high temperature brine, which is then injected back into the first storage zone. This forces a quantity of medium high temperature brine present in the first storage zone into the second storage zone, to maintain a desired quantity of high temperature brine in the first storage zone and a desired quantity of medium high temperature brine in the second storage zone.