alt Hacker NewsI just spent 6 years living off-grid, running 5kw of solar, and 14kWh of storage. I setup a fixed array that I welded together myself. I could certainly see that tracking wasn't worth it even then.
However, in the off grid-setting I did discover some nuance. Sometimes you could really do with some power around sunset or sunrise. In the winter, being able to more reliably run my air-source heat pump at sun-up would have been very handy. Or likewise, some extra power to run the AC (which is the same device) in the early evening in the summer would have also been handy.
There were plenty of cold mornings when I was keeping an eye on the solar grafana dashboard, waiting for that hockey-stick moment when the sun swung into the right place!
I did consider the possibility of setting up an additional east or wast facing array to capture sun at the extremes of the day. Unfortunately that would have required its own MPTT charge controller, and would have just been more complexity in general.
Replies
Some of that you can solve with dual side vertical panels mixed in. Obviously murders their output but you get it when it matters - on the shoulders of the day
I honestly don't think I would be comfortable off grid without 4x+ that size. Of course, environments vary so significantly that these numbers don't translate well when discussing them without geographic context.
My primary concerns would be consecutive cloudy days, and winters with very short days. While my actual heating/cooling needs are more mild than global averages, I think the combination of short daylight hours and increased heating needs makes off-grid solar unviable for climates closer to the poles, especially those not near sea level. I do think relaying on propane or wood for heating might make off grid viable for these locations, but that introduces questions of scalability and increased carbon footprint.
There is some argument that burning wood should be considered carbon neutral if the trees are replanted and used as a renewable resource (Carbon is released to the air, and then captured by the next tree in a cycle), but the land intensive approach wouldn't scale to meet the heating needs of a significant portion of the population. Additionally it ignores the carbon required to grow, harvest, process, and transport the trees or the alternative uses the wood might find elsewhere.
My point is for others to take their local climate into consideration before thinking that 5kw/14kWh would be enough for them to go off grid.
Tom Murphy shows in his excellent book on energy that over-tilting your solar panels by 15 degrees is a good idea (Table 13.2):
https://escholarship.org/uc/item/9js5291m#section.13.4
Basically take your latitude and add 15 degrees and that'll get you good annual coverage.