Convion takes 50-kW pilot SOFC plant with MK351 stacks into operation

In March 2017, Convion took its C50 biogas system into operation. In initial trials, the system achieved a net AC efficiency in excess of 55 %. Fitted with an exhaust gas recovery unit, the Convion C50 is able to achieve an overall efficiency of more than 82 %. At the heart of the plant lie the MK351 stacks developed by Plansee and Fraunhofer IKTS.

In 2015, Convion Ltd. had already developed an innovative cogeneration plant. With a capacity of 20 kW, the system exceeded expectations and has now been upgraded to its full nominal power output of 58 kW. The result: The C50 SOFC power plant. As part of the European project DEMOSOFC, it is shortly due to be installed in a waste water treatment plant operated by SMAT in Turin, Italy. The use of biogas in a low power-output system such as this while still achieving a high level of electrical efficiency cannot be realized with conventional gas engine generator systems. This means that SOFC technology is opening up new perspectives for this kind of installation. With the biogas generated in the plant, three C50-units will provide around 30 % of the electrical and thermal requirements for water treatment.


MK35x stack design from Fraunhofer IKTS and Plansee


Plansee and Fraunhofer IKTS have been working together for several years and are constantly developing the design of the MK35x stack. Pilot systems such as Convion's C50 provide valuable operating data that help both the system developer and the component producers to constantly improve the technology. In order to maximize the gain of knowledge deduced from the test data, Convion, Fraunhofer IKTS, and Plansee have been in close contact ever since it was decided to deploy MK351 stacks.
Thanks to its excellent performance and robustness, the MK351 stack is an impressive development. It was endurance-tested for 20,000 hours in a realistic system environment. Over the test period, performance degradation was very low at 0.7 % / 1,000 h. But improvement activities still continue. Small modifications to the interconnect allowed pressure loss on the air flux side to be reduced from 16.7 mbar to 6.7 mbar at 4 sl/min in the optimized MK352 stack design. This improvement is particularly welcomed to the system manufacturers. It reduces the power consumption of the air feed, which in turn increases the electrical efficiency of the system. The new MK352 stack design is also being endurance-tested. Currently, it has more than 11,000 operating hours on the clock. And again, performance degradation is at a very low level of 0.7 % / 1,000 h. The cycle stability was improved from 0.8 % to 0.5 % per 10 cycles, as was demonstrated in a test over 120 combined RedOx and start/stop cycles.


MK351/MK352 stack -30 layer comparison


(Standard operating conditions: 35 A, 40 % H2 in N2, ƞFU = 75 %, T = 830 °C)

MK351 - previous design MK352 - current design
Power performance > 800 Wyesyes
Long time operation (lifetime)20,000 h
successfully proved
Target: 20,000 h +
Currently: 11,000 h
(still running)
Pressure drop - air side16.7 mbar at 4 sl/min6.7 mbar at 4 sl/min
Long-term degradation< 0.7 % / 1,000 h< 0.7 % / 1,000 h
System cycling stability (RedOx)ΔP/P0 < 0.8 % / 10 cyclesΔP/P0 < 0,5 % / 10 Zyklen



Starting up production of your own MK35x stacks


Fraunhofer IKTS and Plansee are in possession of the intellectual property and know-how for the MK35x stack design. Interested companies can test prototype stacks. Installation kits for furnaces and complete stack modules containing 1, 2, 4 or 8 integrated stacks are available. Hence it is possible to test an individual stack on a test rig or even to carry out fully-integrated system tests. Companies can acquire a license of the technology if they wish to produce their own stacks. Fraunhofer IKTS offers a wide range of assistance in regard to manufacturing technology, production equipment, supply chain know how, services for customized system developments and integration solutions.
A first, non-exclusive license for the MK352 stack technology has been granted to mPower GmbH. This company supplies MK352 stacks to system manufacturers and to its parent company h2e Power, which in turn develops and markets SOFC systems.


Join our presentations at Hannover Fair 2017.


Public Forum, Tuesday, April 25, 2017, 10:20 am
CONVIONs first 50-kW-SOFC-System C50 using CFY-stacks, developed by Fraunhofer IKTS/Plansee
Tuomas Hakala, Co-founder, Convion Oy
Dr. Mihails Kusnezoff, Head of Department: Materials and Components, Fraunhofer-Institut für Keramische Technologien und Systeme IKTS
Siddharth R. Mayur, Founder President & CEO, mPower GmbH

Public Forum, Wednesday, April 26,2017, 4:40 pm
Journey to Mars: O2-generation by ESC-based SOEC stack with Plansee's CFY-interconnects
Stefan Skrabs, Manager Sales & Marketing SOFC, Plansee SE
Jessica Elwell, Program Manager, Ceramatec, Inc.

About us:


Convion Ltd. is a leading fuel cell system provider committed to commercializing SOFC systems in power range above 50 kW for distributed power generation. Convion has significant background in the development of highly efficient and reliable SOFC systems. Convion products are suited for operation with renewable biogas and natural gas, including LNG. By commitment, creativity and agility of Convion team and collaboration with best partners in our value chain, Convion will provide its customers with cost competitive and environmentally sound power solutions. C50 product radically improves reliability of energy supply and efficiency of primary energy use.

The Fraunhofer IKTS develops modern ceramic high-performance materials, customized industrial manufacturing processes and creates prototype components and systems in complete production lines from laboratory scale to pilot plant scale. Furthermore, the institute has expertise in diagnostics and testing of materials and processes. The institute‘s three sites in Dresden and Hermsdorf (Thuringia), Germany, collectively represent Europe‘s largest R&D institute dedicated to the study of ceramics. With decades of solid experience, Fraunhofer IKTS is a leading international contact for all high-temperature fuel cell concerns. The IKTS is one of 69 institutes and research units at locations throughout Germany. The Fraunhofer-Gesellschaft employs a staff of 24,500, who work with an annual research budget totaling 2.1 billion euros.

Plansee is a leader in the field of powder metallurgy, covering the entire production process from the ore right through to customer-specific components. The company was found in 1921 and is an expert for components manufactured from molybdenum, tungsten, tantalum, niobium and chromium. Alloys and composite materials from Plansee come into their own in electronics, coating technology or high-temperature furnaces - wherever traditional materials are stretched beyond their limits. For high temperature fuel cells Plansee develops and manufactures interconnects and metal supported solid oxide fuel cells.

What can we do for you?
Please contact us for further information:

Convion Ltd.
Tekniikantie 12 - 02150 Espoo - Finland - Erkko Fontell
Tel.: +358 40 7544 389 - erkko.fontell(at) -

Fraunhofer IKTS
Winterbergstraße 28 - 01277 Dresden - Germany - Dr. Mihails Kusnezoff
Tel.: +49 351 2553-7707 - mihails.kusnezoff(at) -

Plansee SE
Metallwerk Plansee-Straße 71 - 6600 Reutte - Austria - Stefan Skrabs
Tel.: +43 5672 600 3317 - stefan.skrabs(at) -