Electrically Stimulated Geologic Battery for Hydrogen Energy Storage
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Solution Overview
Problem
Existing energy storage methods, such as pumped-storage hydropower, mechanical storage, compressed air energy storage, thermal heat storage, power-to-gas storage, and flow batteries, face limitations like low energy density, high cost, reliance on large caverns, and inefficiency, making them unsuitable for long-term energy storage solutions.
Innovation Solution
The method involves applying an electrical potential across a rock formation to alter the redox state of species within the formation, injecting water to generate hydrogen, and cycling the redox state to store and release energy, using electrical stimulation to enhance permeability and facilitate energy storage in geologic formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pumped-storage hydropower is used for energy storage, then energy storage capacity is achieved, but energy density is low and susceptibility to drought impacts occurs
Solution Approach 1:
The patent replaces the mechanical gravity-based pumped-storage hydropower system with an electrochemical system using redox-active rock formations. Instead of mechanically pumping water between reservoirs, the invention uses electrical potential to drive redox reactions in iron-rich rocks, storing energy chemically rather than mechanically. This substitution eliminates dependence on water availability while maintaining energy storage capacity.
Solution Approach 2:
The invention changes the fundamental parameter of energy storage from mechanical potential energy (height-based) to chemical energy (redox state-based). By altering the oxidation state of iron species in rock formations through electrical stimulation, the system achieves energy storage with high energy density and independence from environmental conditions like drought.
2Quantity of substance
If mechanical storage relying on gravity-based mediums is used, then energy storage is achieved, but cost is high at approximately $1800 kWh−1
Solution Approach 1:
The patent utilizes abundant, inexpensive iron-rich rock formations as the energy storage medium. Instead of expensive engineered systems with moving parts, the invention uses naturally occurring iron-containing minerals that can be stimulated electrochemically. The rock formation itself serves as the active material, eliminating the need for costly mechanical components and reducing overall system cost.
Solution Approach 2:
The iron-rich rock formation serves multiple functions: it provides the redox-active material, the structural matrix, and the containment vessel. The system uses the natural properties of the rock formation without requiring additional expensive materials or complex engineering, allowing the formation to 'serve itself' as the energy storage medium.
3Quantity of substance
If compressed air energy storage is used, then energy storage is achieved, but large impermeable caverns are required
Solution Approach 1:
The patent utilizes the porous structure of rock formations to store energy at the molecular level through redox reactions. Instead of requiring large-scale caverns to store compressed air, the invention uses the pore spaces and surface area of iron-rich rocks to hold redox-active species. This approach achieves energy storage in distributed, small-scale formations rather than requiring single large caverns.
Solution Approach 2:
The invention replaces the mechanical compression and storage of air in large caverns with electrochemical energy storage in rock formations. Instead of storing energy in the form of pressurized gas occupying large volumes, the system stores energy in the chemical bonds of iron species within compact rock formations, dramatically reducing the volume requirement.
4Duration of action of moving object
If flow batteries are used for energy storage, then extended storage durations and quick power discharge are achieved, but energy density is low and expensive fluids are required
Solution Approach 1:
The patent replaces expensive flow battery electrolytes with inexpensive iron-rich rock formations. Instead of using costly liquid electrolytes that require continuous circulation and specialized containment systems, the invention uses abundant iron-containing minerals that are solid, stable, and require no special handling. This dramatically reduces material costs while maintaining energy storage capability.
Solution Approach 2:
The invention uses porous rock formations to hold the redox-active iron species, eliminating the need for liquid electrolytes and flow circulation systems. The porous structure provides high surface area for electrochemical reactions while containing the active material in a compact, solid-state configuration, achieving high energy density without requiring large volumes of expensive fluids.
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 provides a more efficient and long-duration energy storage solution by enhancing permeability, promoting continuous use of iron-rich geologic formations for energy storage and hydrogen production, and mitigating hydrogen storage requirements, offering a power-to-gas method with increased efficiency compared to current technologies.
Implementation Method 1
applying a first electrical potential across the rock formation and altering a redox state of a species within the rock formation in response to the first electrical potential
Implementation Method 2
reacting water with the iron species within the rock formation to generate hydrogen
Data Source
AI summary
This disclosure describes systems and methods for using electrical stimulation of a rock formation (e.g., a subterranean formation, a subterranean reservoir) to improve, or otherwise enhance, the energy storage capabilities of the rock formation. Many existing rock formations are too impermeable to facilitate energy storage; however, the Inventors have recognized and appreciated that a “geobattery” may be constructed by using electrical stimulation to increase the permeability of a rock formation (e.g., a subterranean formation) such that water (or some other fluid) can be pumped into the rock formation, in particular, a reservoir within the rock formation, and converted into hydrogen to store the energy within the hydrogen.