Mike Strizki is not the only area businessperson tackling the problem of how to store energy generated by solar panels. One solution to the conundrum is to not store the power at all, but sell it back to the power grid, taking a bit of the load off of conventional power sources. This is currently by far the most popular option. It doesn’t require much in the way of extra equipment, and the money generated offsets the cost of installing solar panels.

However, this solution has a major downside: it doesn’t work if the power grid goes down. Solar panels alone can’t keep the lights on after sunset.

Strizki’s solution is the use of a mix of hydrogen fuel cells and batteries. But other area businesses have concluded that batteries alone are the answer. Princeton Satellite Systems, a technology firm based in Plainsboro Village Center, makes the SunStation, a solar power station for home power backup and charging electric vehicles.

Mike Paluszek, founder and president of Princeton Satellite Systems, says he decided to include an array of lithium-ion batteries as part of the system to provide backup when the grid goes down. A 14.4 kw-hour system, enough to provide basic backup for a home, costs about $50,000 with the all-battery system (solar panels included). That’s substantial, but only one-third what a comparable solar-hydrogen setup would cost.

“It uses standard technology that’s available everywhere,” Paluszek said, explaining why he chose batteries over more exotic technology. He acknowledged that batteries have their downsides. “They are not cheap, and they have a finite life cycle.” Other systems use lead-acid batteries, which are cheaper but heavier and bulkier.

Paluszek says he considered other mechanisms before ultimately settling on batteries for power storage. He considered using flow batteries, which are currently being developed by the U.S. Department of Energy. In a flow battery, two tanks of acid sit until needed. The two fluids are then pumped into a reactor, where they exchange electrons and create electricity. While flow batteries have worked well in experiments, they aren’t commercially available yet.

He also investigated using flywheels to store the power. A flywheel system works by accelerating a wheel to high speed, thus storing power as kinetic energy. However, flywheels lose energy quickly due to bearing friction and wouldn’t work well for long-term use.

Ultimately, Paluszek settled on batteries, which give the best performance for cost of the currently available options. Batteries allow users a great deal of flexibility to store power for emergencies, he says, noting that they can be fully re-charged in about half an hour using the grid if there is a temporary restoration of power, as happened in many places after Hurricane Sandy.

It’s also very useful in places where electric companies charge different rates for electricity usage at different times. “You can time shift your power usage in places where it can be really expensive to use power at certain times of the day,” Paluszek says.

Princeton Power Systems, based at 3175 Princeton Pike, is selling similar systems but on a much larger scale. It has built “microgrid” power systems for entire islands that incorporate solar panels, backup gas generators, advanced power management systems, battery storage, and other technologies to provide a reliable, efficient power supply.

Princeton Power Systems looked at the available energy storage mechanisms and decided on an “all of the above” approach, and the company uses hybrid lead-acid, lithium-ion, and flow batteries in addition to flywheels.

Princeton Power Systems Inc., 3175 Princeton Pike, Lawrenceville 08640; 609-955-5390; fax, 609-751-9225. Ken McCauley, CEO. www.princetonpower.com.

Princeton Satellite Systems, 6 Market Street, Suite 926, Plainsboro 08536; 609-275-9606; fax, 609-275-9609. Michael Paluszek, president. www.psatellite.com.

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