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HIGHLIGHTS FROM SOLAR TODAY’s E-BULLETIN FOR SOLAR PROS.
THE BIZ
Increasing PV System Performance
With Active Power Management
By PErry TSAO, PH.D., rALF MUENSTEr, SHELDON MAH,
MAUrICE EAGLIN and SAMEH SArHAN
The California Solar Initiative (CSI) provides incentive rebates to encourage photovoltaic (PV) system adop- tion. As part of the application process for participation in the program, new PV systems are required to
submit data on the system design, including results from the PV Watts calculator and the Expected Performance-Based Buydown (EPBB) calculator. When the results of these calculations are compared to actual performance,
it can easily be seen that the actual performance of the systems is significantly less than expected from these
performance calculators.
It may be tempting to claim that the real problem is with the PVWatts and EPBB calculators over-predicting performance. However, the general consensus of people familiar with these two calculators is that a well-designed
and maintained system will usually exceed the calculated performance. There are some power purchase agreements (PPAs) that take full advantage of this in their business models. This makes the actual underperformance
more significant because it suggests that the potential for improved performance is even higher than shown. It
is also worth noting that the underperformance occurs in both small and large systems — underperformance
is not just an issue in residential installations. Using Solar Magic’s DC monitoring and management solutions,
however, we were able to identify power-sapping problems and boost system performance.
NatIONa L sem IcONDuctOr
Learn more about underperformance by reading the
full version of this article at
solartoday.org/sw.
e authors
employed by
tional Semicon-ctor Corp. in
nta Clara, Calif.
ntact Perry Tsao
perry.tsao@
.com.
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