Subsurface Thermal Storage Using Saturated Steam
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current energy storage systems for heat generated by concentrating solar power are inefficient and lack the capability for long-term, seasonal storage, leading to intermittent energy availability.
Innovation Solution
A subsurface thermal energy storage system utilizing saturated steam as a heat transfer fluid, injected into depleted oil fields for efficient storage and retrieval, minimizing heat loss and parasitic load, and allowing for continuous energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current energy storage systems are used for heat generated by concentrating solar power, then energy can be stored, but the storage efficiency is low and long-term seasonal storage capability is lacking
Solution Approach 1:
The patent introduces saturated steam as an intermediary heat transfer fluid to transfer thermal energy from the solar collector to the subsurface reservoir. This steam intermediary enables efficient energy transfer with minimal heat loss while allowing for long-term storage capacity, resolving the contradiction between storage efficiency and storage duration
Solution Approach 2:
The patent replaces conventional above-ground thermal storage systems with a subsurface geological reservoir system. By utilizing the natural insulation properties of underground formations, the system achieves reduced heat loss and extended storage duration simultaneously, overcoming the limitations of surface-based storage systems
2Quantity of substance
If conventional thermal storage systems are used, then energy storage is achieved, but the systems are complex and have high operational costs
Solution Approach 1:
The patent repurposes depleted oil or gas reservoirs for thermal energy storage, giving these subsurface formations a new function. By utilizing existing geological structures and infrastructure, the system achieves large-scale energy storage capacity without requiring complex artificial construction, thereby reducing system complexity and operational costs
Solution Approach 2:
The subsurface geological reservoir provides natural thermal insulation and containment properties, eliminating the need for complex artificial insulation systems and containment structures. The earth formation itself serves the storage function, reducing system complexity while maintaining large storage capacity
3Duration of action of moving object
If heat is stored for seasonal use, then long-term energy availability is improved, but heat loss increases
Solution Approach 1:
Saturated steam serves as an efficient heat transfer intermediary that minimizes thermal losses during injection into and extraction from the subsurface reservoir. The steam phase change properties enable high-density energy storage with minimal degradation over seasonal timescales, maintaining energy availability while reducing heat loss
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 system provides effective short and long-term storage solutions, smoothing daily and seasonal energy variations, enabling continuous and intermittent energy delivery while reducing heat loss and operational costs.
Implementation Method 1
Fluid for transfer of heat energy from the surface to an underground storage volume (such as a depleted oil field) is saturated steam
Implementation Method 2
large volume storage of heat generated by concentrating solar collectors
Implementation Method 3
Heat energy is injected or removed from a reservoir using wells
Data Source
AI summary
Techniques for subsurface thermal energy storage of heat generated by concentrating solar power enable smoothing of available energy with respect to daily and/or seasonal variation. Solar thermal collectors produce saturated steam that is injected into a producing or wholly/partially depleted oil reservoir that operates as a heat storage reservoir. Some of the saturated steam generated by the collectors is optionally used to generate electricity. Heat is withdrawn from the reservoir as saturated steam and is used to operate an active thermal recovery project (such as a producing thermally enhanced oil reservoir) and/or to generate electricity. Withdrawn heat is optionally augmented by heat produced by firing natural gas. The reservoir is optionally one that has been used for thermally enhanced oil recovery and thus is already warm, minimizing heat losses.