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Siemens Hits Major Milestone in SECA Solid Oxide Fuel Cell Program; No Degradation After 1,500 Hours

Siemens’ high power density (HPD) planar design (top right) compared to its existing tubular cell design ( top left). Next-generation HPD Delta 9 design at bottom. Click to enlarge.

Siemens Power Generation announced the successful testing of its latest solid oxide fuel cell (SOFC) technology that incorporates its high-power density technology being developed under the US Department of Energy’s (DOE) Solid State Energy Conversion Alliance (SECA).

In August 2002, under the SECA program, Siemens Power Generation entered into an $80 million cooperative agreement with DOE’s National Energy Technology Laboratory to develop low-cost Solid Oxide Fuel Cell (SOFC) power systems for residential, automotive and military applications.

Under the agreement, entitled “Small-scale, Low-cost SOFC Systems,” Siemens Power Generation was to develop a new seal-less planar SOFC system.

A prototype 5 kW-class complete system using the SECA technology has operated for 2,800 hours and continues to operate at the Siemens facility near Pittsburgh, PA. It has met or exceeded all of the DOE technical and economic objectives for Phase 1 of the SECA program.

The successful operation of the SECA system is especially noteworthy in that there has been absolutely no degradation of cell or system performance during the period of operation, according to Siemens. With lifetime a key factor in the commercialization of fuel cells, Siemens asserts that its program is the only SECA program to have achieved no cell degradation during extended operation.

A Delphi SOFC system for application in an on-board auxiliary power unit (APU) in vehicles that achieved Phase 1 goals earlier this year, for example, experienced power degradation of 7% over 1,500 hours of operation. (Earlier post.)

While the test duration required by the DOE was 1,500 hours, the system continues to be operated to determine lifetime, peak power and efficiency potential as the performance of the cells improve. They will also be put through further tests in the coming months to assess the robustness of the new stack technology.

Siemens’ new high power density cells are a further development of its tubular cell design and represent a significant step forward towards commercialization of SOFC systems. This new technology has already demonstrated volumetric power density four times greater than the tubular cells, which translates into significantly reduced volume and reduced cost per kW. A number of configurations have already been tested, and further development and tests are planned to qualify the optimum system configurations.

In a tubular SOFC design, air flows through the interior of the cell, and fuel flows on the outside of the cell. At elevated temperatures, the oxygen in the air ionizes and the resulting ions flow through the electrolyte and combine with the fuel on the cell’s exterior. This is an electrochemical reaction, so electrons are released. With proper connections, they can flow through an external circuit as electricity.

The program will be executed in three phases over a ten-year period, and at the end of each phase a prototype SOFC system in the 3-10 kW range will be tested for one or more of the targeted applications. Specific cost targets for each phase will be addressed with the ultimate program target being $ 400/kW in high volume production.

The SECA Phase 1 prototype system test has exceeded our expectations and clearly shows we can successfully enhance our proven SOFC technology for higher performance and lower cost. As we move forward, we are examining various cell designs that substantially increase cell power, stack power density and module simplifications, and results to date have been outstanding.

—Thomas Flower, president of Siemens’ Stationary Fuel Cells division

Recently, Siemens implemented a number of design, material and process changes, and this latest SECA system test validates new manufacturing processes intended to enhance reliability and reduce cost. The next steps are to continue to develop the high power density technology as part of a program that merges the subsequent phases of the SECA program with DOE’s coal-based fuel cell systems program. The ultimate objective of this program is for SOFCs to provide clean power fueled by syngas from domestic coal resources as part of DOE’s FutureGen program.

Siemens plans to commercialize SOFC generators and systems in the 5 kW to multi-megawatt range, with pre-commercial deliveries in the 2006/2009 time frame depending on rating. Siemens is developing SOFC technology under cooperative agreements with the US Department of Energy, through its National Energy Technology Laboratory and the German Federal Ministry of Economics and Technology.




Nice - but 400$/kW in high volume??? 136HP for 40,000 $ ??? Are you crazy! Combine that with high hydrogen price and you get super costly solution. I'm afraid battery is ahead. And if I think of's far, far, far ahead.


Uh they are desiging those for military roles. Dont forget fuel cells are one very important way to quietly make a lot of power in a small unit.


Another point is that SOFC are not poisoned by carbon, like PEM fuel cells are over time. They can use CO from Syngas a fuel too. Also, a 2kW cell would be enough for a APU. That comes out to ~$800, somewhat affordable, and part of a system that reduces engine idle. Onboard reformer or gasifier, of diesel or other carbon/hydrogen/oxygen rich fuels, would likely be necessary. That component will drive up costs.

Paul Dietz

136HP for 40,000 $ ??? Are you crazy!

For stationary markets, that's quite acceptable, especially if used as a topping cycle for a gas turbine. The expected operating life of a stationary generator can be much longer than that of an automotive engine.


A household cogenerator wouldn't need more than 5 kW, maybe not more than 3 kW.  $2000 is darned cheap for such a unit.


Paul Dietz, Engineer-Poet,

You are right if you do not need a lot of power it's cheap but for car...

Thomas Pedersen

One of the newest gas-fired (steam only) powerplants in Denmark came at the cost of $ 1000/kW, so $ 400/kW is pretty cheap for stationary applications, where efficiency really counts.

And the fact that SOFC efficiency does not depend on the scale of the powerplant is a very important benefit. This heralds a more flexible and efficient use of natural gas for power production.

I'm missing an efficiency figure, with and without combined cycle operation.


The efficiency of the bottoming cycle would depend on the scale of the powerplant.

Another recent SOFC announcement came out at 49%, and microturbines seem to start at about 26% at the 30 kW size and work up as they get bigger.  That would give a compounded efficiency of about 62% at a combined power of around 150 kW.


Rolls-Royce has a similar ribbon design. You do not hear much about them, but they are doing some advanced work in SOFCs.

Rafael Seidl

Paul Dietz -

whenever a new power technology is developed, mobile applications tend to come after the stationary ones. It will take a number of years yet before SOFCs will be cost-competitive against natural gas ICEs and turbines in electricity co-generation, never mind vehicle propulsion.

Longevity is the key hurdle at this point and, Siemens appears to have just extended it substantially for small-scale installations. Note, however, that stationary gensets are expected to operate very reliably for 50,000 hours or so between major overhauls. It will be interesting to see how long the new design will last.


"...has operated for 2,800 hours and continues to operate at the Siemens facility near Pittsburgh, PA."

The DOE had the 1500 hour target and they have exceeded that. I have heard of SOFCs
and MCFCs running for 10s of thousands of hours in hospitals and business buildings.

Roger Pham

Great! Now, how about extending the durability of solid oxide electrolytic cells for high temp hydrogen production? This will allow hydrogen to be competitive with BEV from solar or wind energy.


I think there was a link on here about SOFC electrolysis. It is essentially a reversalble SOFC fuel cell. High temperature from concentrated solar thermal or rejected heat at turbine power plants could make H2/O2 production more efficient. You find that oxygen blown gasifiers can produce a more controlled product. This is one way of getting the O2 and H2 to round out the processes.

Cheryl Ho

There are DME developments in China today!Since DME has an advantage of decomposition at lower temperature than methane and LPG, R&D for hydrogen source for fuel cell has been carried out.

If you would like to know more on the latest DME developments, join us at upcoming North Asia DME / Methanol conference in Beijing, 27-28 June 2007, St Regis Hotel. The conference covers key areas which include:

DME productivity can be much higher especially if
country energy policies makes an effort comparable to
that invested in increasing supply.
National Development Reform Commission NDRC
Ministry of Energy for Mongolia

Production of DME/ Methanol through biomass
gasification could potentially be commercialized
Shandong University completed Pilot plant in Jinan and
will be sharing their experience.

Advances in conversion technologies are readily
available and offer exciting potential of DME as a
chemical feedstock
By: Kogas, Lurgi and Haldor Topsoe

Available project finance supports the investments
that DME/ Methanol can play a large energy supply role
By: International Finance Corporation

For more information:

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