OblinEngine is a mechanical long-duration energy storage technology that uses compressed air released at depth to create hydraulic uplift in a water column, producing water flow and hydraulic head that can be recovered through conventional hydroelectric generation equipment.
OblinEngine is currently at TRL 5. The next development stage is an integrated Australian demonstrator intended to progress the technology from TRL 5 to TRL 6.
The current TRL 5 position is supported by completed shallow and deep-shaft testing of the core hydraulic uplift mechanism.
The TRL 6 demonstrator will bring together the compressor, air-delivery system, uplift shaft, hydraulic circuit, turbine-generator, electrical systems, instrumentation and controls under representative operating conditions.
The core OblinEngine mechanism is based on controlled air injection into a deep, water-filled uplift shaft.
When compressed air is released at depth, bubbles rise through the water column. The air-water mixture inside the uplift shaft has a lower average density than the surrounding return-water column.
This density difference produces hydraulic uplift, creating water movement and hydraulic head that can be converted into electricity through a hydroelectric turbine-generator.
Conceptual visualisation. Final demonstrator geometry and equipment configuration remain subject to detailed engineering.
Electricity is used to compress air for later controlled release.
Compressed air is introduced near the base of a deep, water-filled uplift shaft.
Rising bubbles reduce the average density of the air-water mixture, generating upward water movement and hydraulic head.
Water flow is directed through a hydroelectric turbine-generator before returning through the closed-loop system.
Air-water interaction is central to OblinEngine performance. Shaft depth, shaft diameter, injected air flow, bubble behaviour and water-flow conditions all influence hydraulic uplift.
Greater depth also increases pressure at the air-injection point. The relationship between air input, bubble behaviour, water flow and resulting hydraulic head therefore needs to be measured at representative depth.
That is a key reason the next development step is a full-depth integrated TRL 6 demonstrator rather than further reliance on modelling alone.
Illustrative two-phase flow image. Bubble distribution shown is conceptual rather than a measured test image.
OblinEngine is intended to create hydraulic flow and head that can be converted into electrical power using conventional hydroelectric equipment.
This means the distinctive development challenge is concentrated on the compressed-air-driven hydraulic uplift stage, while the electrical recovery stage can use established turbine-generator technology.
Final turbine selection depends on the measured combination of head and flow. Those values will be defined more precisely through the Australian TRL 6 demonstrator.
Representative turbine-generator visual. Final equipment selection depends on validated demonstrator head and flow.
OblinEngine is being developed as a closed-loop hydraulic system. Water lifted through the air-injection process is routed through the turbine-generator stage and returned to the system.
The design objective is to minimise ongoing water demand and avoid dependence on naturally separated upper and lower reservoirs.
Use engineered depth and controlled air injection to create hydraulic uplift within a closed-loop system rather than relying on natural elevation difference.
Compresses, stores and delivers air at the pressure and flow required by the hydraulic uplift process.
Provides the water-column depth required for controlled deep air injection and two-phase uplift flow.
Introduces compressed air at depth and controls air-flow rate and bubble formation.
Routes uplifted water through the energy-recovery stage and back into the closed-loop system.
Converts hydraulic head and flow into mechanical and then electrical power.
Measures electrical, pneumatic and hydraulic performance and controls the integrated operating system.
Operate the principal mechanical, hydraulic and electrical components as one integrated system.
Measure compressor input, turbine-generator output and auxiliary consumption.
Measure air flow, pressure, water flow and hydraulic head under defined conditions.
Determine whether measured performance can be reproduced across multiple test runs.
Characterise operating stability, control requirements and fault behaviour.
Generate evidence suitable for external technical assessment of progression to TRL 6.
No. Compressed air is used to create hydraulic uplift. Electrical recovery is intended to occur through water flow and a hydroelectric turbine-generator.
No. The system uses hydroelectric generation equipment, but its design objective is to create hydraulic head through air-driven uplift rather than pumping water between naturally separated reservoirs.
Depth affects injection pressure, air behaviour and the hydraulic response of the water column. Representative-depth testing is therefore important for progression from TRL 5 to TRL 6.
Not yet. OblinEngine is currently at TRL 5. Integrated electrical performance and round-trip efficiency are among the measurements intended for the TRL 6 demonstrator.
Review the physical evidence supporting the current TRL 5 position and the Australian integrated demonstrator planned as the next step toward TRL 6.