High-efficiency alkaline electrolysers with proprietary stack technology
We design and manufacture advanced systems optimised to efficiently accommodate the variability of renewable energy generation.
With the largest global presence, alkaline electrolysis stands out for its economic viability and industrial scalability. Moving beyond the limitations of traditional systems, our purpose-designed cells incorporate state-of-the-art materials to maximise efficiency.
Renewable energy optimisation: Dynamic response capability to wind and solar intermittency.
Proprietary technology: Full control over stack design, ensuring robustness and industrial durability.
Scalability: Modular solutions of up to 5 MW for large-scale decarbonisation and industrial projects.
Our market objective
Small and medium-sized plants: Projects of up to 10 MW (approximately 200 kg/h), configured modularly using one or more units ranging from 0.5 to 3 MW each.
Compact systems: Scalable equipment of up to 70 kW developed to meet more specific or localised consumption requirements.
Test benches: Specialised systems designed for developers and validators of alkaline components and stacks.
Electrolysers for hydrogen production
AREXn03
Technical specifications
| Technology | Alkaline |
|---|---|
| Size | 10" container (2.989 × 2.435 × 2.591 mm) (length × width × height) |
| Maximum voltage | 15 V |
| Enclosure | 10-foot container |
| Size | 2.815 m long × 0.81 m wide × 2.6 m high |
| Weight | 10 tonnes |
| Nominal process temperature | 80 °C |
| H2 leak sensor in air | Yes |
| Power supply | 400 VAC3P + neutral + earth |
| Nominal H2 gas flow rate | 3 Nm3/h |
|---|---|
| Nominal O2 gas flow rate | 1.5 Nm3/h |
| Nominal pressure | 30 bar |
| Outlet purity (H2) | 99.999% |
| Nominal stack power | 15 kW |
| Total installed power | 25 kW |
| Power setpoint | Constant production, constant power, available power tracking |
| Number of stacks | 1 |
| Interface | Main interface integrated into the test bench via a touchscreen operator panel (HMI). Remote monitoring capability. |
| Demineralised water | ASTM_D1193-91 Type II (alkaline) | 10 tonnes |
We develop our electrolysers based on the experience gained from our projects
Industrial prototypes (0.5 MW): single-stack validation in industrial applications.
SMS Verde Project
In this project, Ariema builds and validates a 0.5 MW electrolysis system for integration into a hydrogen refuelling station for heavy-duty vehicles at airport facilities.
Electrolyser in the VALORH2 project
New materials, catalysts and components for the design and manufacture of a 0.5 MW alkaline electrolyser, producing hydrogen with the required purity for use in fuel cell vehicles.
Multi-MW scaling: 1 MW. Management of complex and multi-stack systems.
IRON NPE Project
A 1 MW multi-stack alkaline electrolyser, representative of on-site hydrogen production at ground-based refuelling facilities.
Our future project: 200 MW/year electrolyser factory
Our development facilities in Huelva have enabled us to complete the innovation cycle, bringing together engineering, prototyping and testing capabilities, and we are already planning our next industrial plant for more technologically advanced manufacturing.
In 2025, ARIEMA Electrolizadores began the process of developing a new electrolyser manufacturing plant in Huelva. The project's main infrastructure has already been awarded public funding at both regional and national level (Andalucía TRADE and IDAE, the Institute for Energy Diversification and Saving).
100% local technology: At ARIEMA, we design, build and test our own electrolysers. We go beyond simply importing or assembling external components to offer a product developed entirely in Spain.
Diverse, high-quality employment: Having full control over the technology enables us to create high-value jobs for a wide range of professional profiles. To secure this talent, we work directly with the University of Huelva, the University of Seville and local vocational training centres.
Driving Huelva’s industrial development: Our manufacturing project is helping to boost the region’s economy. We act as a catalyst for local supporting industries, contributing to the transformation and modernisation of its industrial hub.
Accelerating the energy transition: By manufacturing this equipment in an area with excellent solar resources, we are helping to drive the transition to clean energy in the highest energy-consuming sectors in Andalusia and across the rest of Spain.
Would you like to train your technical team?
In addition to manufacturing the technology, we share our hands-on plant experience. We design bespoke Alkaline Electrolyser Operation and Maintenance (O&M) training programmes tailored to your project.