By Sören Johannsen

SubCtech, an award-winning leader in underwater technologies, founded in 2010 by applied physicist Stefan Marx (CEO), has grown into a maritime powerhouse based in Kiel, Germany. This medium-size enterprise, composed of a diverse team of skilled mechanical and electrical engineers and software specialists, is dedicated to next-generation R&D, custom project consulting, thorough prototype testing, and high-quality manufacturing according to international standards.

The great benefit for customers is a safe and reliable field-tested technology that not only significantly reduces CAPEX and OPEX costs but also greatly reduces the CO2 footprint through less downtime and service calls and longer life cycles; a win-win for industry, the blue economy, and the environment.

Ocean Power Products

SubCtech’s ocean power products are crucial for offshore oil and gas companies; environmental monitoring stations; manufacturers of AUVs, USVs, and ROVs; and other subsea applications. The company’s flagship product line, PowerPacks, features advanced lithium-ion (Li-ion) battery systems with configurations for basic, subsea, vehicle, and custom battery needs, including advanced charging and battery management systems (BMS). These modular and flexible battery power blocks (SPBs), encased in a custom housing, are depth-rated to 6,000 m and designed for a life span of up to 20 years.

One of the key factors in SubCtech’s success with its subsea batteries is the unmatched reliability and adherence to strict safety standards. The Li-ion cells as well as the entire PowerPacks undergo rigorous testing to meet UN T38.3, MIL-STD, DNV, and API 17F compliance standards, along with further customized requirements.

These subsea batteries are specifically engineered for high-capacity, uninterruptible power supply for subsea energy production facilities, capable of operating even in extreme conditions. Our batteries undergo intensive testing for heat resistance, shock and vibration tolerance, and electromagnetic compatibility to ensure they meet the stringent standards our clients expect and heavily rely on.

The batteries automatically protect themselves from potential issues, safeguarding the system from damage and ensuring operational safety. They are equipped with features to disconnect in case of over- or undervoltage, over temperature, overcharge, overcurrent or short circuits, with a high number of sensors and new KI-based algorithm to eliminate false alarms and detect critical states. Compared to traditional alkaline primary batteries, Li-ion PowerPacks provide robust high-current operation, functioning at sub-zero temperatures, able to handle peak currents efficiently, and suitable for long storage or operating times. These attributes precisely meet demanding subsea and offshore applications.

 

 

Subsea Energy Storage System

Recently, SubCtech developed a 2-MWh subsea energy storage system (ESS), setting a milestone in its commitment to sustainable energy storage solutions. This ESS stands out due to several key innovations. Its design is based on scalable and independently operable SPB modules, allowing for flexible configurations, from small kilowatt-hour setups to multimegawatt-hour installations. The ESS uses field-proven, DNV GL-certified lithium-ion batteries, ensuring reliability and safety.

The advanced BMS provides real-time diagnostics, redundancy, intelligent balancing, and autonomous subsea operation with minimal maintenance. It is applicable for both energy storage and powering AUVs, sensors, and subsea equipment. This combination of technical maturity, scalability and autonomy sets it apart in the global subsea energy market.

The ESS, with a Technology Readiness Level of 6 (TRL 6 according API 17Q), is currently in operational use in the oil and gas sector. The system has proven its value in the field, where it effectively supports the demanding power requirements of offshore operations.

One of SubCtech’s customers, a major international oil and gas company based in North America, impressed by the ESS’s performance and reliability, recently placed an order for an additional complete system. This order underscores the ESS’s success and the growing demand for sustainable, high-capacity power solutions within the subsea industry. It represents a milestone in the commercialization of large-scale subsea battery systems.

 

 

Global Growth

As the global demand for ocean power products increases, SubCtech has been experiencing rapid growth, supplying products to clients around the world. To accommodate this growth, SubCtech has doubled its workforce to 76 employees and plans a significant expansion of its production facilities in 2025.

Our UN T38.3-certified Li-ion batteries are safely transported worldwide via airline cargo, thanks to our professional sales partner network that ensures seamless service availability even in diverse regions.

Future Vision

Looking to the future, SubCtech is committed to advancing as a global leader in ocean power solutions, as well as ocean monitoring systems, such as our OceanPack RACE system, currently deployed on German research vessels, such as the RV Polarstern. It performs continuous CO2 and pH monitoring; meteorological and hydrographic data logging (salinity, temperature, oxygen, etc.); and real-time satellite transmission to global networks, including the Integrated Carbon Observation System and SOCAT, which brings together, in a common format, all publicly available surface water data from the global oceans. SubCtech’s systems contribute critical data to climate research and carbon cycle modeling, and they are recognized for their reliability in extreme polar and tropical environments.

The company actively seeks strategic partnerships to extend its network and deepen its impact in the international oceanology sector. With continued innovation in subsea energy storage and monitoring, along with a robust commitment to environmental responsibility, SubCtech is well-positioned to set new standards in sustainable marine technology.

 

 

SubCtech is a trusted partner in the marine and subsea technology sectors, known for its innovative solutions, such as Li-ion PowerPacks and the pioneering Subsea ESS. These products deliver reliable, field-proven technology that meets the demanding standards of the offshore industry.

The key benefit for customers lies in significantly reducing CAPEX and OPEX costs. Longer operational intervals, fewer service calls, and reduced downtime not only optimize efficiency but also lower the CO2 footprint—offering a clear win for industry, the blue economy, and the environment.

The recent success of the ESS in operational deployment within the oil and gas sector and the subsequent re-order by a key customer further underscores the effectiveness and reliability of SubCtech’s solutions in real-world applications. As SubCtech continues to innovate and grow, it solidifies its role as a pioneer in sustainable power and monitoring technologies for the marine environment.

For more information, visit www.subctech.com or contact: info@subctech.com.

Sören Johannsen is the COO and marketing manager of SubCtech.