Contrary to some confused bloggers, solar panels produce the
most electricity over the course of a year when pointed south, not west. A recent report from the Pecan Street Research Institute started a chain of articles with increasingly inaccurate conclusions.
The lemmings at Quartz, Gizmodo, and Grist,
followed each other off the cliff of delusion saying that homeowners
could produce more power by pointing their solar panels west, rather
than south. The title of an article “Are Solar Panels Facing the Wrong Direction?” on Greentech Media seems to have started the lemmings rushing cliff-ward, even though the article itself got the facts right.
It simply ain’t so. The study found that the
average house in a sample of 14 houses with west-facing solar arrays
produced more electricity than the average of 24 houses with south
facing arrays in Austin, Texas during the three months from June 1 to
August 31st, 2013.
The study (which I obtained from Pecan Street) specifically says
“Over the course of a full year, a south-facing orientation produces
more total energy than other orientations.” In addition, Brewster
McCracken, the president and CEO of Pecan Street, told me that he did
not expect that the finding that the west facing arrays produced more
energy even during that three month period was statistically
significant, given the small sample size.
Point It West
That said, the study concluded that there were significant benefits
to pointing solar panels west. While the highest annual electricity
production will be produced with south facing panels, west-facing arrays
are much better at reducing peak loads in climates with
air-conditioning driven peak demand, such as Austin.
According to the study, a equal sized west facing system would have
produced 49% more electricity during the peak demand hours of the summer
months than a south facing system. Only 58% of electricity from south
facing systems was used in the home, with 42 percent being sent back to
the utility grid. Fully 75% of electricity from west facing systems was
used in the home, with only 25% sent back to the grid (see charts.)
Because they help more to reduce peak load, and put less strain on
electricity distribution systems, west-facing PV systems may have more
value to the grid than do south-facing systems, despite producing less
total energy over the course of a year.
Conclusion
More solar arrays should be pointed west, but not because they
produce more power that way. They should be pointed west because, in
many cases, the power they produce is more valuable. Utilities and
governments should structure their incentives accordingly. McCracken told me that some of the utilities in his area don’t even
offer incentives for west facing solar arrays because “they don’t
produce enough energy.” Those utilities are just as confused as the
media lemmings who think you get more energy by pointing solar panels
west.
http://www.forbes.com/sites/tomkonrad/2013/11/22/your-solar-panels-arent-facing-the-wrong-way/?ss=business%3Aenergy
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