Multi-mode subterranean energy system
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Solution Overview
Problem
Existing subterranean hydroelectric systems face limitations due to flow limitations in underground recipients, which restrict the generation of hydroelectric power, especially when high volumes of water need to be handled quickly.
Innovation Solution
A multi-mode subterranean energy system that includes an intake tunnel, a vertical shaft with a turbine/pump unit, an underground cavity, and water flow control means to manage water flow through different tunnels, allowing for various operational modes such as Direct Energy Production, Stored Energy Discharge, Direct Energy Storage, and Indirect Energy Storage, enabling efficient power generation even with flow-limited recipients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If water is discharged directly from the upper reservoir to the subterranean recipient through the vertical shaft, then high power levels can be achieved, but the system cannot handle flow limitations of the recipient
Solution Approach 1:
The system divides the water discharge path into two separate tunnels: the recipient tunnel for direct high-power generation and the cavity tunnel for flow storage and regulation. This segmentation allows the system to handle flow limitations by storing excess water in the cavity while maintaining high power output through the recipient tunnel.
Solution Approach 2:
The underground cavity acts as an intermediary storage chamber between the vertical shaft and the subterranean recipient. It buffers flow variations, allowing the system to maintain stable high-power operation even when the recipient has limited flow capacity.
2Power
If the system operates in direct energy production mode for high power output, then power generation is maximized, but energy storage capability is lost
Solution Approach 1:
The system is designed to perform multiple functions through different operational modes: direct energy production, stored energy discharge, direct energy storage, and indirect energy storage. The same physical components (tunnels, shaft, cavity, turbine) serve different purposes depending on the operational mode, providing both high power generation and energy storage capabilities.
Solution Approach 2:
The system dynamically switches between different operational modes based on energy demands and water availability. Water flow control means adjust the configuration of tunnels and shafts in real-time, allowing the system to transition from power generation mode to energy storage mode and vice versa.
3Adaptability or versatility
If the cavity tunnel is opened for energy storage operations, then water flow to the recipient is restricted, but if closed for direct power production, then energy storage capability is lost
Solution Approach 1:
The dual-tunnel design separates the energy storage function (cavity tunnel) from the power generation function (recipient tunnel). This allows independent operation of each function - the cavity tunnel can be opened for storage while the recipient tunnel maintains power generation, or vice versa, eliminating the trade-off between storage and power capabilities.
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
The system enables flexible and high-power electrical energy generation by controlling water flow and utilizing the turbine/pump unit in different modes, effectively addressing flow limitations and optimizing power production in scenarios where underground recipients have restricted capacity.
Implementation Method 1
water from a surface reservoir is passed through a turbine before ultimately being released into a subterranean recipient, and where hydroelectric power can be extracted at high power levels
Implementation Method 2
storing energy by pumping water from the cavity to the reservoir
Implementation Method 3
the gravitational potential energy drop of water brought down from the surface to a cavity of 1 km depth is in the range of several GWh
Data Source
Figure 1
AI summary
A multi-mode subterranean energy system and a related multi-mode subterranean energy production method are disclosed. The system comprises subterranean tunnels (2, 3, 8, 9, 14) connecting an upper reservoir of water (1), an underground 5cavity (10) and a subterranean recipient (15), a turbine/pump unit (4), and water flow control means (5, 6, 7). The system optionally can be operated in four modes.