For the last few years millions of dollars have gone into raising the efficiency of solar panels by a couple of percentage points here and there. It's an important project: if we can make those panels convert one percent more of the sunlight that hits them to electricity, that additional one percent really adds up when hundreds of thousands of panels are installed.
And so solar firms have been trying to tackle the efficiency issue, using cutting-edge science like proton beam exfoliation and computer-modeled complex systems engineering. But a promising initial study out of Texas shows that we might be able to boost rooftop solar output by a few percentage points without using technology more complex than a compass and a cordless drill.
As reported by GreenTech Media's Katherine Tweed today, a study of 50 solar homes in Austin, Texas hints that simply facing rooftop solar panels west instead of south can make those panels supply a bigger chunk of their owners' energy consumption.
The study by the Pecan Street Research Institute will be extended past Austin to other states, possibly including California, Tweed writes.
The results are a little counterintuitive: the sun stays in the southern half of the sky for those of us in the Northern Hemisphere, and it would seem to make sense that if you're putting up solar panels on a fixed mount that can't track the sun, facing them more or less south would mean more power output.
But west-facing solar panels in the study produced far more power during periods of peak demand than more conventionally oriented panels. In the Austin area, peak power consumption happens between 3:00 and 7:00 p.m., when west-facing panels are pointed right at the sun.
As shown in this graph from Pecan Street Research, that made a huge difference in how much power was generated during the hours when people want it most: west-facing panels in the study put out 49 percent more peak period power than south-facing panels.
By creating more power when the homes beneath them needed it most, west facing panels were able to meet an average of 37 percent of those homes' daily energy consumption, as compared to 35 percent for south-facing panels. And if a local utility pays more for Net Metered power during peak periods, the financial return might be greater for west-facing solar panels.
It's far too early to read very much into the study, with just 50 homes examined in one geographic location. Conditions elsewhere might be very different: aiming your solar panels west might not be a great idea if you live in a place in California where the fog rolls in off the Pacific at 2:00 p.m.
But it's a great reminder that some of the advances we need in solar technology might not require 21st Century technology to implement. And perhaps most importantly: those of you with west-facing roofs no longer need to assume rooftop solar won't work for you.