Powers the Globe with the MEGAMIE

Fuel cells (FCs) differ from conventional power generation systems in that they can use hydrogen as a carbon-free power source. With built-in electrochemical converters, FCs can combine hydrogen and oxygen in the air to produce energy directly without the carbon dioxide byproduct. As such, they maintain high efficiency while emitting less carbon.

For over four decades, Yoshinori Kobayashi has been at the forefront of revolutionary developments with FCs. Our latest innovation in this space came in the form of a solid oxide fuel cell (SOFC) called MEGAMIE. This SOFC was the result of joint research with Japan’s New Energy and Industrial Technology Development Organization (NEDO).

The Great East Japan Earthquake in 2011 strengthened Kobayashi’s drive to commercialize SOFCs. With their high efficiency and low carbon emissions, SOFCs are a potential solution to address the tension between energy security and environmental sustainability that many countries face.

Kobayashi put this fortified conviction into action. In 2015, a 250 kW class system prototype was set up at Kyushu University, and by 2017, MEGAMIE had its commercial launch in Japan. As of February 2020, the Kyushu University prototype has achieved a continuous run of 25,000 hours.

The process of developing MEGAMIE was filled with many intellectual and engineering puzzles. The toughest challenge, Kobayashi recalled, was to figure out how to build a robust power unit with ceramics which are essential for SOFC function. Each MEGAMIE unit uses a cell stack – a cylindrical substrate tube designed to trigger reactions for power generation. Cell stacks are made entirely of ceramics and take about a year of development.

The pressurizing system uses in MEGAMIE combines the delicate ceramics with a gas turbine that must withstand extreme temperature and pressure conditions. These different components had conflicting properties but they had to be integrated into a single complex system – a significant engineering challenge. “Many industry-leading players and research institutes have tried to commercialize similar fuel cells,” Kobayashi noted, “but combining these technologies proved to be too difficult.”

To build such a complex system, Kobayashi brought together experts from different domains. To be sure, there were challenges in the collaboration, and there were even conflicting opinions among the team on what aspects of the system to prioritize fixing. “But the key to success is that everyone works as one to overcome such conflicts,” Kobayashi acknowledged.

“Today, we live in a world where productivity and speed are prized above all, at the expense of teamwork and collaboration. Sometimes though, not taking time to consider different expert opinions causes unexpected problems. Working as a team and leveraging our own individual strengths – whether chemicals or system mechanics – we were able to fill in the gaps in each other’s knowledge. Ultimately, this collaboration made MEGAMIE better.”

Other big challenges were increasing production yield and ensuring quality control throughout the supply chain. Part of Kobayashi’s concern was the “balance of plant” (BOP), which refers to all the supporting components and auxiliary systems that a power plant needs to deliver energy apart from the generating unit itself. For MEGAMIE, this term applies to micro gas turbines, heat exchangers, piping, valves, and electrical components. Kobayashi needed to ascertain that the suppliers of BOP components would be willing to provide the parts in good condition even as MEGAMIE had yet to go to market.

“To ensure the quality of all raw materials, you have to deploy your people to the manufacturers’ factories,” Kobayashi said. “Many suppliers would have been reluctant to do this, but our partners willingly allowed us to do so, and I am thankful for that. Project members also kept talking to the partners. They negotiated costing of the BOP components and made improvements to boost the performance of the SOFC, helping alleviate partners’ concerns.”

Among the many factors that distinguish MEGAMIE from other SOFCs is its versality. It is a high efficiency power system that can use multiple types of fuel gases – from city gas and LPG in local infrastructure to methane gas from sludge, food waste and agricultural waste. Furthermore, MEGAMIE can accommodate multiple forms of hydrogen.

Another key differentiating factor is MEGAMIE’s ability to leverage pressurized gas, as in conventional power systems which use gas turbines. "Pressurized gas produces more power,” Kobayashi explained. “When you look at the shape of the cell, you notice it needs to be sealed only at two locations at both ends of the cylinder. That is sufficient to shield the fuel flowing inside the cell from the air outside. With fewer sealing locations, the cell could be more readily combined with gas turbines.”

How MEGAMIE produces power

In 2019, the first commercial 250 kW class MEGAMIE started operation at the Marunouchi Building, housing numerous shops and offices at the heart of Tokyo. So while still far from the goal of delivering sustainable power to the rest of the world, MEGAMIE is already generating impact in Japan.

Now, the question on Kobayashi’s mind is how Mitsubishi Power can make the MEGAMIE technology more available to a wider market. For instance, since 2014, preparations for mass production of the cell stack have been underway with NGK Spark Plug Co., Ltd., a top ceramic manufacturer.

Cost is one of the barriers to greater market penetration. MEGAMIE must be offered at a much more reasonable price to increase adoption across the globe. Kobayashi and his team are working to address this cost challenge, which includes increasing cell output density, enhancing material quality, simplifying production processed and collaborating with partners to optimize the supply chain.

Another issue is how to ensure safe and efficient operations. Polymer electrolyte fuel cells used for automobiles work within a relatively low-temperature range of 60-100°C; thus, start/stop functions would not pose major difficulties. However, SOFCs work in temperatures as high as 900°C, and take much longer to start or stop.

Yet, if there is anything the Great East Japan Earthquake taught Kobayashi, it is that the world urgently needs MEGAMIE. And just as he solved the many challenges in MEGAMIE’s development, he is now finding a way to bring this game-changing technology to the world.