Offshore Pumped Storage Cavity Design for Wind Energy

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Solution Overview

Problem

The challenge lies in effectively storing and releasing energy generated from offshore wind turbines, as conventional pumped storage plants are limited by location and incur significant line losses and construction costs due to the need for long-distance energy transmission to mountainous regions, and existing solutions struggle with high energy losses and restricted site selection.

Innovation Solution

A water pumped-storage plant (PSW) with a storage cavity tunneled into the sea floor or solid land, utilizing hydrostatic pressure for energy storage, eliminating the need for artificial upper reservoirs and allowing energy to be stored directly near the wind farm, with the option to also use compressed air as a storage medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If energy is transmitted via long transmission lines to mountainous regions for storage, then energy can be stored using existing pumped-storage facilities, but significant transmission losses and construction costs occur

Engineering Contradiction:
Improvetransmission lossesVSAvoidtransmission line infrastructure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention divides the storage system into modular components: a hollow body for water storage, a machine house with pump-turbine unit, and separate ventilation shafts. This segmentation allows the facility to be constructed in discrete sections, reducing overall complexity and enabling phased construction without requiring complete transmission line infrastructure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary air cushion between the water storage hollow body and the environment, allowing pressure equalization and ventilation without direct water exposure. This intermediary system enables energy storage functionality while simplifying the connection to existing infrastructure and reducing transmission requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional pumped storage power plants are used, then energy storage is achieved, but location is severely limited to mountainous regions

Engineering Contradiction:
Improvelocation flexibilityVSAvoidenergy potential
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The invention transitions from traditional vertical elevation-based storage (mountainous regions) to horizontal offshore deployment. The hollow body is positioned on or in the bottom of a body of water, utilizing the seabed as the foundation rather than requiring high-altitude terrain. This dimensional shift enables deployment in coastal and offshore locations, dramatically expanding site selection flexibility while maintaining energy storage capability through the pump-turbine mechanism

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The machine house serves multiple functions: housing the pump-turbine unit for energy conversion, providing access for maintenance, and serving as a structural anchor for the hollow body. This multi-functional design reduces the need for separate infrastructure components, making the system adaptable to various offshore locations without requiring specialized mountainous terrain features

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If artificial upper and lower reservoirs with open water surface are used, then pumped storage operation is enabled, but extremely few suitable locations are available

Engineering Contradiction:
Improvesite selectionVSAvoidartificial reservoir construction
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs a hollow body with watertight walls that can be constructed from modular sections, allowing flexibility in shaping and positioning. This shell structure replaces the need for extensive artificial reservoir construction, as the hollow body itself contains the water storage function. The modular nature of the hollow body sections enables assembly in various locations without requiring specific geological conditions for natural reservoir formation

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses a standardized hollow body design that can be replicated and deployed in multiple locations. The hollow body serves as a copyable template that maintains consistent functionality across different sites, eliminating the need for custom-designed artificial reservoirs at each location. This standardization reduces construction complexity and expands site selection to any location with suitable seabed conditions

Inventive Principle:
Principle #26Copying

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

Enables efficient storage and release of large quantities of electrical energy directly at the wind farm site, reducing energy losses and site restrictions, and allows for economic utilization of intermittent wind energy by equalizing grid fluctuations, while using inexhaustible seawater as a storage medium.

Implementation Method 1

at least one pump for pumping water out of the cavity (6)

Methodology Applied
Scientific EffectHydraulic pump: Pump

Implementation Method 2

at least one turbine for generating electricity when the cavity (6) is flooded with water

Methodology Applied
Scientific EffectHydroelectric turbine: Turbine

Implementation Method 3

a ventilation shaft (5) extending from the second end of the cavity (6) to the land surface (1)

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP2725143B1Pump storage device for energy storage
Publication Date: 2019.05.15 ROOS THOMAS
  • EP2725143B1 patent drawingFigure 1~2
  • EP2725143B1 patent drawingFigure 3~4

AI summary

The plant has a storage cavity including an end section, which is arranged in a bottom of a water body, a stone and/or a sediment region (3) of a marine slope. Another end section of the cavity is provided below a land surface. A machine underground chamber (7) includes a connection to the former end section. The chamber includes a machine set, a pump for pumping water from the cavity, and a turbine for current generation during flooding of the cavity with water. A water inlet is provided for the chamber. An aeration shaft (5) extends from the latter end section upto the land surface. An independent claim is also included for a method for storing and releasing energy by a pumped storage plant.