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Frequently Asked Questions
Clear answers about how FLASC works, where it can be deployed and how it scales.
If you have a project-specific question, talk to our team.
Technology and Performance
| FLASC stores electricity as compressed air using a hydro-pneumatic liquid-piston system. During charging, electricity drives hydraulic equipment that compresses air into a pressure containment system. During discharge, the air expands through the liquid pistons, driving the system in reverse to return electricity to the grid. |
| FLASC is designed for long-duration applications ranging from approximately 4 to 100+ hours. Because power and capacity are independently scalable, the system can be configured for different duty cycles without relying on underground caverns or battery oversizing. |
| The modular architecture supports systems from approximately 500 kW upwards. Smaller configurations are suitable for water-adjacent onshore and industrial applications, while multiple modules can be combined for multi-megawatt, utility-scale offshore projects. The final rating is tailored to the site, grid connection and operating requirements. |
| Power and storage capacity can be sized independently. The Energy Conversion Unit and Liquid-Piston Modules determine how quickly the system charges and discharges, while the volume of the Pressure Containment System determines how much energy is stored. Additional modules can therefore be added according to the project’s power or duration requirements. |
| FLASC systems are designed for approximately 70% round-trip efficiency. The liquid-piston process keeps compression and expansion close to isothermal by exchanging heat with the surrounding water, reducing the thermal losses normally associated with compressed-air storage. |
| No. FLASC uses liquid pistons to compress and expand air. This allows heat to be transferred efficiently to and from the surrounding water, reducing the thermal losses and system complexity associated with conventional compressed-air turbomachinery. |
| No. The liquid-piston system uses a closed hydraulic circuit, while the pressure containment system stores compressed air. The surrounding water remains outside the system and acts as a natural heat sink, helping dissipate and absorb heat during compression and expansion. |
| Operating pressure depends on the selected system configuration. Current designs can operate at pressures of up to approximately 350 bar, allowing FLASC to use established pressure-rated components and standard steel-pipeline supply chains. |
Deployment and Applications
| FLASC is designed for both offshore and water-adjacent onshore applications. Offshore configurations can be integrated with fixed or floating renewable-energy projects. Onshore applications include ports, coastal sites, lakes, reservoirs, industrial water basins and suitable river-adjacent locations. In every configuration, the surrounding water enables efficient thermal management. |
| Co-locating storage with offshore generation allows energy to be managed behind the meter, reduces curtailment and makes better use of existing offshore infrastructure and space. It can also ease pressure at grid landing points while harnessing the ocean as a natural heat sink for efficient compression and expansion. |
| A suitable site normally requires access to a sufficiently large water body, a viable grid connection, space for modular power equipment and a need for four or more hours of storage. Potential locations include industrial basins, ports, coastal sites, reservoirs and suitable river-adjacent facilities. Final suitability is confirmed through a site-specific assessment. |
| FLASC is designed for water depths of approximately 40 to 400 metres, covering both bottom-fixed and floating offshore applications. Because the system is pneumatically pre-charged, it does not depend on external hydrostatic pressure to store energy and can achieve high storage density in relatively shallow water. |
| Potentially. Existing pressure-rated pipelines and other offshore assets may be suitable for energy storage, subject to an assessment of their integrity, remaining design life and operating limits. FLASC has evaluated pipeline-repurposing concepts in which storage value can be combined with deferred decommissioning or abandonment costs. |
Lifetime and Sustainability
| FLASC stores energy using compressed air and a water-based hydraulic fluid, without flammable battery chemistries or chemical energy-storage hazards. The system is built predominantly from steel, supporting established supply chains, long service life and end-of-life recycling. Environmental impacts and mitigation measures are assessed for each deployment site. |
| FLASC is designed for a 30-year operating life without cycling degradation. The system uses established hydraulic, electrical and offshore components, supported by remote monitoring and planned preventive maintenance. Maintenance requirements depend on the configuration, but the architecture is designed for intervals of five years or more between major planned interventions. |
Validation and Commercialisation
| FLASC first demonstrated the technology through a marine proof-of-concept system in Malta, followed by an extended testing campaign and peer-reviewed publication of the results. The technology has also received a Statement of Feasibility from DNV. A 125 kW grid-connected pilot in Rotterdam now provides a platform for system qualification, performance validation and grid-compliance testing. |
| Yes. FLASC’s core hydro-pneumatic energy-storage technology is protected by granted patents in Europe, the United States, China and Japan. The company continues to develop and protect further innovations associated with the system architecture, control strategy and applications. |
| Cost depends on the required power, storage duration, site conditions and installation method. For an indicative 2030 comparison, FLASC estimates a Levelised Cost of Storage of approximately €89/MWh for a 100+ MW, 10-hour system. A project-specific assessment is required to establish the appropriate configuration and commercial case. |
| FLASC supports projects from initial feasibility and system sizing through to detailed configuration, controls and integration. The company supplies its proprietary modular energy-storage technology and works with established engineering and delivery partners to provide the pressure containment, installation and wider project-integration scope. |
| FLASC stores electricity as compressed air using a hydro-pneumatic liquid-piston system. During charging, electricity drives hydraulic equipment that compresses air into a pressure containment system. During discharge, the air expands through the liquid pistons, driving the system in reverse to return electricity to the grid. |
| FLASC is designed for long-duration applications ranging from approximately 4 to 100+ hours. Because power and capacity are independently scalable, the system can be configured for different duty cycles without relying on underground caverns or battery oversizing. |
| The modular architecture supports systems from approximately 500 kW upwards. Smaller configurations are suitable for water-adjacent onshore and industrial applications, while multiple modules can be combined for multi-megawatt, utility-scale offshore projects. The final rating is tailored to the site, grid connection and operating requirements. |
| Power and storage capacity can be sized independently. The Energy Conversion Unit and Liquid-Piston Modules determine how quickly the system charges and discharges, while the volume of the Pressure Containment System determines how much energy is stored. Additional modules can therefore be added according to the project’s power or duration requirements. |
| FLASC systems are designed for approximately 70% round-trip efficiency. The liquid-piston process keeps compression and expansion close to isothermal by exchanging heat with the surrounding water, reducing the thermal losses normally associated with compressed-air storage. |
| No. FLASC uses liquid pistons to compress and expand air. This allows heat to be transferred efficiently to and from the surrounding water, reducing the thermal losses and system complexity associated with conventional compressed-air turbomachinery. |
| No. The liquid-piston system uses a closed hydraulic circuit, while the pressure containment system stores compressed air. The surrounding water remains outside the system and acts as a natural heat sink, helping dissipate and absorb heat during compression and expansion. |
| Operating pressure depends on the selected system configuration. Current designs can operate at pressures of up to approximately 350 bar, allowing FLASC to use established pressure-rated components and standard steel-pipeline supply chains. |
| FLASC is designed for both offshore and water-adjacent onshore applications. Offshore configurations can be integrated with fixed or floating renewable-energy projects. Onshore applications include ports, coastal sites, lakes, reservoirs, industrial water basins and suitable river-adjacent locations. In every configuration, the surrounding water enables efficient thermal management. |
| Co-locating storage with offshore generation allows energy to be managed behind the meter, reduces curtailment and makes better use of existing offshore infrastructure and space. It can also ease pressure at grid landing points while harnessing the ocean as a natural heat sink for efficient compression and expansion. |
| A suitable site normally requires access to a sufficiently large water body, a viable grid connection, space for modular power equipment and a need for four or more hours of storage. Potential locations include industrial basins, ports, coastal sites, reservoirs and suitable river-adjacent facilities. Final suitability is confirmed through a site-specific assessment. |
| FLASC is designed for water depths of approximately 40 to 400 metres, covering both bottom-fixed and floating offshore applications. Because the system is pneumatically pre-charged, it does not depend on external hydrostatic pressure to store energy and can achieve high storage density in relatively shallow water. |
| Potentially. Existing pressure-rated pipelines and other offshore assets may be suitable for energy storage, subject to an assessment of their integrity, remaining design life and operating limits. FLASC has evaluated pipeline-repurposing concepts in which storage value can be combined with deferred decommissioning or abandonment costs. |
| FLASC stores energy using compressed air and a water-based hydraulic fluid, without flammable battery chemistries or chemical energy-storage hazards. The system is built predominantly from steel, supporting established supply chains, long service life and end-of-life recycling. Environmental impacts and mitigation measures are assessed for each deployment site. |
| FLASC is designed for a 30-year operating life without cycling degradation. The system uses established hydraulic, electrical and offshore components, supported by remote monitoring and planned preventive maintenance. Maintenance requirements depend on the configuration, but the architecture is designed for intervals of five years or more between major planned interventions. |
| FLASC first demonstrated the technology through a marine proof-of-concept system in Malta, followed by an extended testing campaign and peer-reviewed publication of the results. The technology has also received a Statement of Feasibility from DNV. A 125 kW grid-connected pilot in Rotterdam now provides a platform for system qualification, performance validation and grid-compliance testing. |
| Yes. FLASC’s core hydro-pneumatic energy-storage technology is protected by granted patents in Europe, the United States, China and Japan. The company continues to develop and protect further innovations associated with the system architecture, control strategy and applications. |
| Cost depends on the required power, storage duration, site conditions and installation method. For an indicative 2030 comparison, FLASC estimates a Levelised Cost of Storage of approximately €89/MWh for a 100+ MW, 10-hour system. A project-specific assessment is required to establish the appropriate configuration and commercial case. |
| FLASC supports projects from initial feasibility and system sizing through to detailed configuration, controls and integration. The company supplies its proprietary modular energy-storage technology and works with established engineering and delivery partners to provide the pressure containment, installation and wider project-integration scope. |