Which Direction Should Solar PV Panels Face?
Here’s an article that discusses the compass direction that solar panels should face, both to maximize total power and to create the optimum alignment of peak generation with peak load. Although I found this interesting, the most intriguing part is this: we’ve had solar panels on our roofs for 40 years and we’re just now figuring out which way to aim them? I guess I too would also assume it best to point them in the direction of the equator, i.e., south if you’re in the Northern Hemisphere, but it seems a bit strange to be having an epiphany on this as we go into 2014.
It’s not that we’re just figuring this out, we’ve known this for years (and I’ve been writing about it for years.) Wind has the same problem. It’s because of the way we pay for renewables: because we only pay for energy (net metering, the wind PTC) we end up with configurations which optimize energy output instead of optimizing the value of the energy produced. Here’s something I wrote about this in 2009: http://www.altenergystocks.com/archives/2009/04/our_undiversified_wind_portfolio_1.html
You make excellent points here, but facing solar panels to the west actually create (slightly) more TOTAL energy, in addition to more peak energy.
I looked at the study, and while they found that the homes in their sample produced more total electricity, it was only during a 3 month period June-August of one year, and the sample size was only 14 west-facing arrays. Even if the data sample were large enough to draw a statistically significant conclusions (which I doubt it is), the result would be unlikely to apply to different locations or months of the year.
Given the small sample size, 14 west and and 24 south facing arrays, a single home with shading issues could have produced the unexpected result, and this may in fact be likely. Given the incentives to produce more power, people will only install a west-facing array if they have a good reason to; south-facing is the default. Hence, I would expect that the south-facing arrays, on average, were installed with less attention to shading issues.
Statistical issues aside, even if we assume that west facing arrays in Austin produced more electricity than south facing arrays with comparable shading and maintenance, there are a number of possible causes which would not generalize to other seasons or parts of the country. One such cause would be frequent cloudiness in the morning which burned off in the afternoon. I do recall many summer days like that when I lived in Austin (1999-2002.)
Many previous studies and all physical models show that total output from we-facing solar is lower, and will be in the summer. In the winter, shorter days will reduce the output of west-facing arrays more than south-facing arrays. PV produces less power when hot as well.
All that said, we can increase the value of solar output by pointing panels southwest or even west depending on the local utility’s load curve, but it’s nonsense to draw broad conclusions from a tiny statistical sample that contradicts all previous results as well as geometry.
We need to point them in the direction of being machine mass produced via nuclear… But not just any nuclear.
The molten salt reactor is meltdown proof and has much higher temps… PERFECT for Brayton cycle NG plants. The MSR needs to be designed specifically for that common powerplant. Add NG for peaking (at no cold start inefficiency, either) when solar and wind are “down”.
This will allow the anticipated exponential expansion of solar and wind without the need for expensive storage while using the minimum of the cleanest fossil fuels, most efficiently.
You got me all riled up: http://www.forbes.com/sites/tomkonrad/2013/11/22/your-solar-panels-arent-facing-the-wrong-way/
Ha! Nice going….