National Semiconductor's new technology
can help solar PVs to manage the shade better
National Semiconductor has commissioned a survey conducted
by Greenberg Quinlan Rosner Research, to study the effect
of shade on performance of Solar Photo Voltaics (PV). Survey
points out, most installers of solar photovoltaic (PV) systems
(54 percent) believe no amount of shading is acceptable
on residential and commercial rooftop solar installations.
Due to the characteristics of solar arrays, small amounts
of shade (for example, shading of less than 10 percent of
the surface area of a PV system) can lead to disproportionate
power losses of more than 50 percent due to mismatch in
power generation. National Semiconductor going to introduce
a technology later this spring, which manages the power
generation differences due to shade and recoup up to 50
percent of power losses associated with partial shading.
The shades can be caused due to trees, chimneys and dormers,
and intermittent debris including falling leaves, bird droppings
and dust. In the case of structural shade, even correctly
installed solar systems can be partially blocked from the
sun at certain times of the day or during certain days of
the year.
The outputs of survey are:
1. 41 percent of solar installers encounter shade when selling
or installing a PV system.
2. Of those, 87 percent "frequently" or "always"
design around shade.
3. Another 28 percent "frequently" or "always"
tell the owner that solar cannot be installed.
The study also revealed that installers often place smaller
solar arrays in order to avoid shady sections of customers'
roofs. Roughly one third of installers said designing around
shading increases system costs, and many said they lose
time doing so. Additionally, nearly half of all installers
have seen solar arrays whose performance has been impaired
by shading.
"Shade happens, and customers and solar installers
are picking up the tab," said Ralf Muenster, director
of National Semiconductor's Renewable Energy Key Market
Segment. "There is a real need to educate the market
that shade does not mean 'lights out' for solar. Shade can
be mitigated."
Shade need not be terminal for solar power. While solar
cell manufacturers have poured millions of dollars into
research and development to improve conversion efficiencies
by a fraction of one percent, solving power mismatches from
different panels within a single solar array, whether caused
by shade or other problems, can yield improvements in system
performance of more than 30 percent.
The technology named SolarMagic power optimizer from National
Semiconductor is a new energy management product that will
mark National's strategic entry into the photovoltaic market.
The power optimizer will enable installers to embrace shade,
placing PV systems on roofs previously regarded as receiving
inadequate levels of sunlight to justify a solar array.