Tuesday, May 22, 2007

Portable Power Sources

The MIT Club of Nortern California's Semiconductor Entrepreneurship series hosted the third event in its series on Portable Communications on May 16th, 2007. This panel discussion focused on Portable Power sources and had an impressive lineup of speakers. The panel was moderated by Scott Chou of Gabriel Venture Partners and consisted of Dr. Ross Dueber, CEO of Zinc Matrix Power, Carl Schulenburg, CEO of PowerMems, Dan Squiller, CEO of PowerGenix and Dr. Steven Visco, Founder and VP of Polyplus battery. Scott Chou presented a concise overview of the landscape and challenges in portable power generation and storage. Each of the panelists described their unique power generation and storage mechanisms - a truly impressive array of technologies.

Scott Chou pointed out that Clean Energy was rapidly gaining favor in the VC world with $2.36B in funding of 124 deals in 2006 vs $820M and 74 deals in 2005. Of this funding Ethanol/biofuels/clean coal topped the list with solar a distant second in total funding, though the number of deals was 34 to 27. He then discussed the impact of energy density. Diesel gives about 11000 W-hr/liter while methanol at the low end is only about 4400 W-hr/liter. Other biofuels span the range. In comparison a Li-ion batter is about 400 W-hr/liter, though its not quite a useful measure for this application. He also touched upon the negative impacts of biofuels in driving up the costs of food crop and the search for non-food crop as sources of biofuel. Interestingly algae topped his list delivering 95000 liters of oil/hectare with the nearest competitor being chinese tallow at 6545 liters of oil/hectare. So, the algae win hands down :-) This was a nice overview of the clean energy scenario as it stands. Thanks to Scott for all the data.

The panel's focus of course was on portable power sources. The worldwide battery spending is on the order of $60B, with $20B of that going to rechargeable batteries. So, it certainly is not a niche market. Zinc Matrix appeared to be the leading contender for the longest lasting batteries for laptops and other portable devices. No wonder Intel Capital is an investor. However, the PowerMems technology seems to challenge it with charges lasting for the lifetimes of the device, on the order of years. However, the application is for relatively low power wireless sensor devices requiring power in the mW range. Their technology harvests ambient energy from vibrations, heat and solar energy and stores in a 3D nanostructure battery. Their focus seems to be mostly on the broad spectrum efficiency of power generation and less on the storage, though. Polyplus has interesting technology where they focus on Lithium-seawater, Li-sulfur and Li-air batteries. You would expect that seawater, despite having the advantage of being a plentiful electrolyte, would pose some corrosion problems. However, the key to their technology is the ability to keep the Li anode chemically protected while being electrochemically active. They claim energy densities of 6000 W-Hr/liter. Then there was PowerGenix, who developed next generation Ni-Zn batteries. They claim to be cheaper and smaller than Ni-Cd and Ni-Mh batteries and promise an upset in the rechargeable battery space.

Overall a very interesting panel, with fuel cells being the only key missing technology - the Ultracell panelist could not make it. Clearly, battery technology is the key challenge in portable devices. Device performance follows the almost exponential semiconductor scaling and the power requirements follow, but battery technology barely keeps up a linear improvement in performance and almost no cost reduction. Truly revolutionary approaches are needed if the status quo is to budge by much. Certainly this panel provided some interesting approaches to this very challenging problem.


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