Panel casts doubt on MEMS for energy harvest

AMSTERDAM, The Netherlands – A panel discussion on energy and MEMS brought the one-day MEMS Executive Congress Europe to life, here as differences of opinion were exposed. The congress is an annual event organized by the MEMS Industry Group trade association.

The debate was sparked by panelist Wim Sinke, program development manager for solar energy at the Energy Research Center of the Netherlands. "MEMS may be talking about energy but I have to tell you energy is not talking about MEMS," Sinke said. "You are not going to beat PV [photovoltaics] except in some small-scale and specialist applications."

Sinke did indicate that MEMS devices could find markets supporting an industry where the renewable energy will be focused on solar energy and wind generation. "There is increasingly two-way traffic [on the grid] and MEMS could find a place introducing intelligence and control at all levels," he said.

Fellow panelist Eric Yeatman, professor of microengineering at Imperial College London, backed up Sinke pointing out that global energy generation capacity stands at 4-terawatts while individual energy harvest devices generate milliwatts at best.

Moderator Bert Gyselinckx, general manager of the Holst research center in Eindhoven, The Netherlands, did question whether anyone was seriously proposing MEMS as large-scale energy source but did acknowledge that there may be better small-scale energy sources than MEMS, including Peltier effect devices and photovoltaics.

It was conference audience member Robert Andosca, CEO of MicroGen Systems Inc., that carried the fight back to the panel. "I agree you're not going to replace large-scale energy generation with MEMS. But you can use a small amount of energy to save a large amount, a leverage effect." Andosca went on the give examples.

Andosca's own company is close to launching a narrowband vibration harvester that can generate 100-microwatts dc that could be used to power some simple wireless sensor nodes. "If you can save 10 minutes off each use of a clothes dryer in the United States by putting a humidity sensor in the rotating drum that would save $1.3 billion per year in energy. He acknowledged that sometimes small-scale photovoltaics may be useful but not always. "In sensors used to monitor cows they tried solar cells, they get dirty," said Andosca.



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Panel on MEMS in Energy at MEMS Executive Congress Europe. From left to right: Bert Gyselinckx, Wim Sinke, Professor Eric Yeatman and Harry Zervos.