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California regulators cut incentives for rooftop solar even further
(www.canarymedia.com)
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this post was submitted on 04 Dec 2023
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I write this from a place where electricity is provided by a crown corporation (government ran corp - SaskPower) and also have a net-zero rooftop solar system, and small scale solar like this is quite inefficient compared to grid-scale stations. I very much agree that there is some sovereignty in producing one's own power, however, grid-scale generation is much more effective, both in cost and generation efficiency.
SaskPower has really had no recent incentives for rooftop solar and they only pay about half price for power returned to the grid, effectively discouraging widespread development of rooftop solar.
They have instead proposed an interesting alternative where a homeowner could purchase a portion of a larger scale facility and be credited for the electricity that portion generates. Crowd-funded electricity generation, essentially. This is, of course, much more attractive when the provider is essentially a company owned by the public, not a private, profit seeking entity. But, I think it could be a promising alternative to enable homeowners to offset their electricity bills while being a better option for the overall grid.
Can you explain a bit better on the magnitude of these differences and why they exist? Thx
Solar panels are most efficient when sunlight hits them as close to perpendicular as possible. Large scale arrays tend to be 1 axis sun tracking, which yeilds about twenty percent more power with the same panels compared to optimal angle fixed arrays at cost of some small motors, a computer, and incresed space between the panels. Small scale and or rooftop by contrast tends to be space constrained, and often ends up at bad angles.
It still works obviously, but between the fixed angle and cramped space you see significant losses compared to what the same pannel could output in a large scale array.
Cost wise, the most expensive part of any small scale solar array tends to be the labor to install it. Panels are now cheaper per square m than fence posts, inverters are expensive but not that expensive, but design and construction are not. It is a lot faster and easier to have a team start at one end of a field and put down racks in assembly line fashion than having someone come out and design a system, another team climb roofs to install conduit and brackets, then a bunch of electrical work, before finally getting an electrical inspector to come out and sign off on it.
None of this is to say that small scale is useless or you shouldn’t do it if you can, especially in California where Pacific Gas and Energy have spent the last forty years outright refusing to do any maintenance or infrastructure investments unless the govement picks up the entire tab and lets them raise some of the highest rates in the nation, but there definitely is an argument to be made that if the government is paying for it either way than spending should go to the place that gives an extra twenty to thirty percent output for the same cost.
Good points.
So this leaves us comparing the inefficiency of fixed-angle panels to the inefficiency of transmission over a grid. IIUC, grid inefficiency is huge. So wouldn’t it be wise to upgrade the home kits to add sun tracking and a motor?
Very few homeowners are going to want to pay even more for tracking. You'd also need more space to accommodate the swing of the array, and it also brings about more consideration for wind loads. Grid inefficiencies are still present with rooftop systems as well, as excess power is sent back to the grid.
In principle I think it would be ideal to have an easily accessible rooftop with a rooftop terrace so the rooftop space is functionally usable. But then indeed the frames that hold the panels up high enough so you could sit under the panels as they move would have to be rock-solid and thus costly. But quite useful if they could flip 180° when there’s hail (and unconditionally at nighttime). I’m brainstorming.. is that crazy talk? Is this something that’s so cost prohibitive that the costs could never be recovered? It obviously wouldn’t be a budget option but some people might be willing to pay more just to have the luxury of extra terrace space.
I’ve heard the down-to-earth lean budget approach is to have the panels on the ground because of the need to periodically quickly cover them up in hail storms and do various other maintenance tasks and adjustments. I don’t have ground space though.
IIUC, feeding the grid is more energy efficient than feeding batteries, which I assume is why you have an assumption of grid-feedback, correct? Alternatively, what about installing an extra big hot water tank so there is never unconsumed power?
Yes, a panel system like that would be very complex and costly, with little additional benefit. If it hails with the intensity to damage panels so often in a certain location, it'd probably be best to look at other generation alternatives.
A hot water tank is still essentially unconsumed power, and likely worse in a warm climate, as heat will leak causing your cooling system to work harder.
The US national average grid loss is about 5%, which I figured would often be more than made up for by a lack of shadeing at larger installations. While grid losses are likely to increase as we move to renewables, that’s down to the fact that prime solar and wind spots tend to be much farther away from major north American cities than the suburban power plants that feed them currently. Given the density of said cities, rooftop solar just takes to much space to provide the necessary power for a taller building.
While you can find some home scale ones with sun tracking, given the weight and foundation requirements they almost always need to be built on the ground, and do cost even more. You also have the aesthetic constraint, as while panels flat against the roof only annoy the most Nimby of Nimbys, large person sized poles like this are harder to hide, even if i think they look neat crystal flowers.
https://www.solarreviews.com/content/images/blog/post/focus_images/41_Dual-Axis-Solar-Tracker-2-970.jpg
Finally, tracking panels do have higher routine maintenance requirements, as there are now parfs that can move, wear, and jam. It doesn’t happen often, so one technician can dozens of square miles by themselves, but it takes a lot more time when you need to schedule around individual homeowners and a wide array of different types of install as compared to see a notification on the monitoring software when you get into work, hop in truck with a set of standerd replacement parts, go to panel and fix.