tbleakne wrote:Cool temperatures can easily increase output 10%.
Wow, that is quite significant! We just installed a SunPower system on our roof (with 360W panels to maximize production per unit area) and SunPower claims that their efficiency loss at higher temperatures is more modest than "typical" panels. If this is the case, I wonder whether we'll see much benefit from our lower temperatures up here in the mountains.
tbleakne wrote:I just woke up to the fact that SCE is now stating on their web page that ALL residential customers will be transitioned to TOU in 2018, per a CPUC order from 2015. Being grandfathered under NM 1.0 does not protect you from being moved to TOU.
It seems to me that this could have the effect of motivating more customers to install solar for the first time, to take the bite out of peak usage charges.
In our case, whether "peak" is from 2 PM - 8 PM versus 4 PM - 9 PM probably isn't much of a concern. Either way, our production during peak hours appears to be pretty low due to shading. We installed a relatively large system, 6.48 kW DC, to compensate for the fact that we may be losing roughly 40% of our theoretically possible production to shade, primarily in the afternoon hours. In March, our best production is from roughly 9:30 AM to 1:30 PM (PDT). Obviously this means that it will take significantly longer for the system to pay for itself (I'm guessing 10-12 years), but we'll still come out ahead in the long run, and have the satisfaction of producing clean energy.
For us, it also helps that we don't use air conditioning, thus keeping our daytime usage from getting too high. That said, there are some days when we wish we had A/C. I'm speculating that with panels on the roof, our solar heat gain may be mitigated somewhat.
Finally, I have a comment about PV production, shading, and clouds that's probably obvious to PV veterans. During the hours when the majority of our panels are in shade, I've noticed that clouds or haze in the sky can help by diffusing sunlight, thus enabling more solar radiation to reach the shaded panels. Our best overall production has occurred on days that are mostly sunny but with significant high clouds. Totally clear and crisp days aren't quite as good for production, by a factor of about 10% less.