The future of solar doesn't track the sun
90 comments
·May 1, 2025adamcharnock
barathr
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.
hx8
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.
sneak
In these sorts of rare situations it is of course possible to run a generator to charge everything up. Off-grid doesn’t mean on an island.
The insane energy density of fossil fuels means this is an excellent “emergency” back-up plan should the sun not shine often enough.
hx8
I'm not sure it's rare to live about 45°N, where we start to see >9 hours of sunlight in the winter. The intersection of places that are both above 45°N and very cloudy (Portland, Seattle, London, Detroit, Copenhagen, Dublin, Vancouver) or in high altitude probably includes a good chunk of HN readers. Northern Europe gets down to about 6 hours of daylight in the winter. If you're in one of these regions, and you plan to use a generator to augment your energy needs, I don't think that's considered an emergency as much as a secondary power source. If one of your goals is decreasing carbon emissions then a diesel generator is going to set that back.
Other regions will have their own considerations, but the primary concern is balancing harvesting sunlight with heating/cooling requirements. I'm just encouraging people to do their own homework for their own situation when considering off grid. I've seen a lot of people under build and end up spending way too much to heat their homes in winter.
UltraSane
What is the appeal of living off-grid?
freehorse
Sometimes the appeal is not in the "off-grid" itself, but in living in a remote location where having access to the grid is impossible or inconvenient (it does not have to be too remote either to not have easy access to the grid).
sneak
You don’t have to be around other people, and all the hassles that human society and population density entail.
Some people are really into that. I’m really into same-day Amazon delivery and 30 minute latency on fresh pizza that I didn’t have to cook.
mchannon
I've been in solar energy as my primary vocation since the 1990's.
I've built solar cars, I've built solar panels, I've installed solar panels, I've designed solar trackers. I know this industry inside and out.
I'd never heard of an east-west array before (though I did experiment with one-cell-wide "crinolations" at 60 degree angles, did not find any value to using them but it was a different application where low-angle light wasn't a factor). I'd never thought of such an array on this scale, at this low angle, before.
I don't think most of the people reading this article quite understand that this is a completely different kind of array topology to flat-plate fixed-tilt, or tracking-based systems. Do yourself a favor, if you consider yourself intellectually curious, and if you came away from skimming this article thinking there's nothing new under the sun, read it again with a keener eye toward the novelty of it.
mrshadowgoose
I actually use this exact example when encouraging careful attention to paradigms where a fundamental variable is slowly but consistently changing.
It's essentially equivalent to a boundary on a phase diagram: Cost/Watt has fallen past a critical threshold, and suddenly this dramatically different approach just makes more sense.
philjohn
I have an east/west array on my roof, as my house is positioned with the front facing west.
In the winter it's outperformed by a south facing array (northern hemisphere) but in the summer the east array gets a ton of sun before midday, and crucially, it's getting a ton of sun when the temperatures are a bit cooler, so it performs very well.
photochemsyn
Another interesting configuration is vertical bifacial panels aligned on North-South axis and interspersed with farming rows. Low-cost panels make it feasible and it doesn't much block agricultural production if the panel rows are spaced far enough apart.
weinzierl
We researched this thoroughly in the early 2000s and came to pretty much the same conclusion even back then.
For us the main problem was the reliability of the mover. If enough panels face the wrong direction for long enough it is worse than facing the sun in a good enough fixed position all the time.
Our angle was to use a simple motor that runs with constant speed and use a special patented gear (called VIAX) to turn that simple movement into a sun following motion. The bet was that a still simple mechanical gear would be more reliable than complicated electronics.
In the end none of our simulations made us confident any moving solution wouldn't eat the profits.
EDIT: For anyone interested, here is the patent. I think it is a really nice idea. https://patents.google.com/patent/EP0114240A1/en
Gibbon1
I saw some guy in Britain that replaced his old fence with one made of solar panels because the cost difference between that and traditional was nil.
null
johnea
This was going to be the gist of my reply.
I don't have the depth of experience with solar installations cited in your comment, but I have worked with systems that expected automated moving parts to continue to function in an outdoor environment. They all required near continuous maintenance.
Having a high level of cynicism regarding the utility industry, I wonder if the preference for moving parts is due to the requirement that only a large company with a constantly employed force of service personal can manage such a system. This would provide a certain amount of cost-of-entry that only large utilities could provide.
To quote what a utility company's compliance office once said to me, in a different context, "Only big companies can do that".
tgsovlerkhgsel
Looking at the graphs, the tracking arrays may have the added benefit of generating power in the mornings and evenings. If everyone builds non-tracking arrays, power during peak will become almost worthless if solar is a big part of overall generation capacity, so the economics might change even with panels being cheap.
Of course, just building 2x as many permanently tilted panels might also work.
Edit: the article actually addresses this: "[fixed setups] can pack 250% more installed power into the same space when compared to a single-axis array" - so even if only the power in the morning/evening has value, there is little reason to install tracking ones.
hinkley
This is one of the areas where double sided panels reportedly win out. You can orient them to morning/evening light and they shed heat by convection better. Hot cells produce less electricity, which is why it’s difficult to construct Maxwell’s Demon from eg infrared-sensitized photovoltaics and band gapped radiators.
leoedin
Yeah - you can’t talk about renewable energy generation without also considering when it is generated.
Then future price of energy will be incredibly time dependent. Finding a way to generate at a different time than everyone else - whether by east/west panels or time shifting with batteries or building a different kind of renewable generation is where all the big profits will be.
philjohn
It already is on wholesale markets - in the UK you can get on Agile Octopus which gives you half hourly prices. When there is a glut of renewables on the grid you can end up being paid to use energy.
This highlights the need for grid scale storage (be it batteries, pumped hydro or something else) to balance Solar PV, and to bridge gaps when the wind isn't blowing.
yummypaint
Demand isn't fixed in time either, though. Industrial processes that presently run at night to use cheap power will switch to daytime when it makes sense to do so. Summer mid-day also has the highest electricity demand all year in many places due to air conditioning, so arguably solar is addressing one of the biggest stress points.
ericd
Not an expert, but my understanding is that the challenge there is that a big cost in industrial production is the initial capital outlay for the equipment, and oftentimes to pay that back reasonably, you need to run the equipment nonstop. Also, some processes are challenging to stop/start.
WillPostForFood
"summer mid-day also has the highest electricity demand all year in many places due to air conditioning,"
Peak electric demand is 3-7pm in the summer. You might think you could then just set panels to to optimize for afternoon, but especially in winter, you get a big peak between 6-9am.
ceejayoz
Power during those lull periods will get expensive, and that’s likely to result in some farms with permanently tilted panels that prioritize those periods over peak overall production.
Space is cheaper than maintenance and breakdowns in many cases.
ac29
> If everyone builds non-tracking arrays, power during peak will become almost worthless if solar is a big part of overall generation capacity
During peak solar yesterday in California wholesale power was $5-6/MWh (<1c/kWh).
The CA grid is routinely over 100% renewables during springtime. The excess is handled by having a lot of batteries, exporting energy, and curtailments.
Calwestjobs
but, 70% of MY! yearly households electricity consumption is literally into [PV!] hot water. Hot water tank is cheapest energy storage device on planet. and i do not have to worry to shower in noon, i can just charge my water tank during day, even when im not home. and use hot water in evening. for very little price - no need to use heat pump, resistive heater is super cheap. hot water tank can be made even DIY to lower price even more.
utility charges me so much for electricity that even tho i payed for 15 kWp roof mounted east west system literally literally ORDER OF MAGNITUDE more than prices showed in that article, AND i still save money by not buying electricity from grid !
that how much utilities are charging us, yes they need to manage all those wires, manage power plants, etc. i do understand where that cost comes from, but still, solar in residential is so cheap that installing PV on roof and directly consuming it will save you money.
So for industry/ manufacturing there will be extremely high incentive to add PV + battery even when it wont cover 100% of their loads. utility+ onsite PV+battery.
Again, back to my hot water system, 80% of year i am 100% "off-grid" for hot water [PV!]. even on days it is cloudy ! And 99%-0% of PV rest of year... And from april to October my electricity draw from grid is almost zero.
so whole residential USA can be essentially "off-grid" huge part of year with just small battery, your tv, notebooks draw almost nothing over the course of the day compared to your energy need for hot water. and less residential is on grid, easier it is to manage electricity for other sectors of economy.
this contraption from ETH Zurich can store iron/iron oxide to generate hydrogen, without storage loss! for years, without compressing hydrogen and without other cons of "standard hydrogen storage. essentially it can be thought about as hydrogen storage - it can "store" 10s of megawatts inside of a standard basement. - [https://ethz.ch/en/news-and-events/eth-news/news/2024/08/iro...]
and you do not need to make electricity from that hydrogen, you can heat your house directly with hydrogen, just by replacing 30$ burner in your existing furnace!
so you complain about "peak" power excess, and i say and i show it to you that this "peak" solar power can be used to charge that extremely cheap storage device in summer and expend that storage over winter for heating house and making hot water. when sun is not shining.
and again, calculate how much kWh is your need for heating and how much is for hot water and you can clearly see that extremely huge part of current residential energy need can be either "onsite off-grid" with this contraption + small LiFePO battery or to be on-grid and take only small loads like tv, notebooks from grid and having heating + hot water "onsite off-grid". and most importantly cheap.
ratio of kWh for your heat and for your other appliances ! ! ! !
So essentially we can charge our heating system in summer, store energy WITHOUT LOSS until winter and heat with that energy in winter. right now!
just sketch/draw for yourself timeline containing - PV + storage contraption in that link + small LiFePO battery. and you can see how huge part of energy we do not really need to draw from "grid".
small towns can even make their own shared storage, prices for SEASONAL energy storage are even lower then current prices for electricity drawn from grid....
So this physical, economical actual contemporary possibility makes me mad every time i see just another youtuber or other kind of influencer, post about just another battery technology promising who knows what, in who knows what timeframe.
we do have energy storage technologies capable of providing citizens of USA with clean energy RIGHT now, RIGHT here. for whole year, day and night. without buying one drop of oil from tyrants, dictators who literally literally kill people right at this moment.
[https://apnews.com/article/russia-ukraine-war-drones-kharkiv...]
this world is so frustrating ! XD
rsync
I read, and appreciated, your entire comment - thank you.
You describe a simple and elegant solution to some portions of these problems and what you are doing with your hot water "battery" is smart.
I am forced, however, to ask:
Where do you live and how large is your family ?
My suspicion is that you do not live in the United States and your family is relatively small ... ?
Modern, "first world" ("global north" ?) 21st century homes do not match your model in a number of different ways:
- Unlimited, temp stable hot water comes from a tankless water heater. People don't "run out" of hot water anymore.
- A family - even a relatively small family - runs a 30A dryer daily. Our family of five runs it 1-2x daily.
- Many, many people now have electric cars and some households have two of them.
- I agree that laptops and phones and personal electronics are a rounding error here but microwave ovens, toasters, coffee percolators, etc., are not - and people use them. I will note in passing that both our dishwasher and our microwave oven require 20A circuits.
I am optimistic that we (as a society) can satisfy these demands with solar power - I just want to make sure you appreciate just how much demand for electricity a modern US household has.
FWIW, we are planning on going entirely off-grid, purely solar with lifepo batteries, in the next 18-24 months.
lm28469
Americans basically live like energy is unlimited, free and has no side effects, the rest of the world doesn't have that chance, last time I checked the average US household used anywhere between 3x and 4x more electricity than the average EU household
They tend to prefer huge houses with relatively complex designs (less optimal in term of area/volume ratio) / poor insulation, they make up for it by relying on tech for heating/cooling pretty much year round.
Your tankless water heater is a good example of something that is completely inadequate for solar setups, they draw insane amount of energy over very quick period of time. But I think that's the core of the issue, if you want to keep all the nice things modern American houses have you're going to need a lot of money and a lot of sun. On the other hand if you're a bit more frugal, with so called "passive house", you can get by with a much smaller setup.
> I will note in passing that both our dishwasher and our microwave oven require 20A circuits
And a tankless heater will need 5 times that, unless you're using gas but I wouldn't count that in a "modern first world 21st century home".
Calwestjobs
Everyone should calculate how much is consuming in kWh, recalculate gas into kWh, wood into kWh, propane into kWh.... then it starts making sense for ordinary people. Even for how much energy leaves their house. To use kW / kWh for everything.
" 1)- tankless"
more than half of USA has water tanks. both water tanks and tankless heaters have expected working life, after taht they have to be replaced either way.
Tankless heaters are more efficient if you think only about AMOUNT of energy, but water tanks are there to lower your PRICE of hot water. (or spread load over longer time for usecase as your offgrid) So yes, with tankless you are doing best in standard "old" grid situation, where price for electricity for customer was same throughout day, (some tariffs can have different price in night) (or when you ask Ask This Old House)
AND with PV! on roof and tank in basement, households are providing service for utility because A) they do not export solar at noon, they are putting that energy to water tank, B) they do not import energy during evening peak hours. so less generation / "base load" needed to exist, to operate, service, manufacture.
but there are new things like solar export which will change grid. and people have to adjust, or they can just install expensive battery paid with gov subsidies (by "utility")... residential customer can either use cheap electricity during day to heat water tank or utility can charge for "stabilising" of grid multiples of that price.
so customers incentive should be to have hot water from PV on his own roof. and when they do not have enough solar energy they can charge rest from grid. and lowering need for importing from grid by 80+% per year... for hot water energy.
"2)dryer "
how much is that kWh ? can it run during day when there is availability of PV ? Or atleast one of those cycles can run during day?
" 3) electric car "
I am one of them but unfortunately i am working from home and have nonstandard schedule (20-45 miles per day + once per week trip to buy groceries in town 130 miles ) so i can charge my car from PV, not many people can do that. but they can have water tank on PV and car on grid... or if they use one car only sporadically, then that one can maybe charge from PV ?
my electric car can be charged by 2kW from standard outlet for 10 hours to add 62 miles of range, in summer when i do not want huge loads or i can connect it to faster charger. one car takes daily roughly same amount of energy as 2 people need for hot water...
"4) appliances "
how much is that kWh ? starting current can be higher, sustain power can be lower. starting power can be lowered by using "starter circuit" - bunch of capacitors connected to motor, but lot of motor apliances already have it. coffee percolator is essentially water tank so you are already doing it ;) 20A is not much, some appliances can be connected to 240v if it is available. or adding more circuit breakers if you have slot for them, and spread loads between circuits.
"5) rest" not waste, save, use on site first, then grid. most people live grid first... i do not mind grid
im not saying everyone should go off-grid, because high-rises can not. but everyone who can, should atleast be able to have 5-10 kWp PV on roof just for hot water, and it can be used in emergency for other things (not necessarily same lifestyle). such small pv + hot water tank as a predictable load connected to well sized PV can make PV be payed sooner. and having connection to grid, with possibility of getting payed for export of excess in future for powering highrises...
my system got payed in 6 years because i use a lot of energy directly. lifetime of inverter is presumably 10 years and panels 20 years so i have presumably next 4 years energy for free. then i have to replace inverter,... if those devices last longer, saving is even bigger.
bbarnett
I didn't read your entire comment (sorry), but wanted to support your water tank statement.
I live in an area with frequent, often day long power failures during winter storms. So my house is designed around that.
When I bought a new hot water tank, I spent a little extra for the super insulated one. The result?
I can take a shower during a power failure, and still another not as hot 24 hrs later! When you consider that the first shower injected cold water into the tank, that's fairly impressive.
On long power failures, on the third morning I can even take a lukewarm shower, with no cold water at the shower (I have individual hot/cold controls). This is far preferable to a shower at 5C water temp (from my well in winter)
And where did any eacaped heat go? Why... into my house! Surely not a loss.
So yes, water tanks rock.
Calwestjobs
Yeah, similarly with insulation / good building practices, my house can lose power in coldest of days and i do not have to put on hoodie for 2 days. (not heating by other means like wood, which i do not have) it is not big house tho. it is insane to me that in country where there are tornadoes, hurricanes, wildfires hundreds of times per year, we do not do this / build like this by default.
In europe, there is possibility to be on "energy spot prices", essentially utility will charge you energy market prices. today price at noon was almost zero. last Sunday, prices were negative - they literally pay you to draw from grid. but at evening, price can be quite high.
so having simple time relay / or more complex minicomputer directly reading energy market prices and switching loads can even earn you some money. it is not money making business but overall price can drop significantly. it is also an economic incentive to buy battery storage and actually got to paid it off.
Enabling citizens to do good thing is underrated.
people with "standard" contract are essentially subsidizing industry, corporations which have cheaper electricity because of bundling with residential customers. which makes weird and complicated incentive structures. essentially anti-market behavior in country which boasts itself in "capitalistic" structures... and slowing adoption of renewables, because it looks like they are more expensive than they actually are.
tzs
I wonder if you could make a DMD [1] where instead of mirrors the tilting part is tiny solar panels?
The panels would only have two positions, but you could install half the DMD devices so that the two positions are south and southeast, and half so they are south and southwest. You could then have half your panels southeast and half south in the morning, all of them south midday, and have southwest and half south afternoon.
That would get you at least some tracking and it should be mechanically a lot more reliable than the systems that move large panels.
DMDs were designed for use in video projects, where they have to move the mirrors more times in 4 hours of video than a solar array would need to move the panels in 1000 years.
[1] https://en.wikipedia.org/wiki/Digital_micromirror_device
turtlebits
Too much complexity and maintenance. Solar panels are dirt cheap, and with fixed mounts, zero maintenance. The rack you mount them on costs more than the panels.
The only reason I can see for added complexity is if you're space constrained, and in almost all cases, not cost efficient.
bob1029
A DMD is a really good thought, but I don't know if the surface area would work out at scale.
I think the power handling limit of typical devices is something like 100W/cm^2.
The UV from the sun would also degrade these devices faster.
csr86
Nature has come up with moving limbs on animals, but none of the trees seem to be tracking the sun. Branches are in fixed positions.
gpm
There are some plants that track the sun, e.g. https://youtu.be/w-adcjH-xyk?si=Pcx4ucVe1oVwbdH4
It's definitely the exception rather than the rule though.
null
edent
We have an east/west roof with solar on it. It is less efficient than our previous roof which was pure south - but it smooths out the generation and gives us more electricity in the evening.
I have some pretty graphs at https://shkspr.mobi/blog/2020/04/comparing-solar-panel-gener...
null
rini17
When panels are cheap what about vertical mounting? Less susceptible to hail and snow. And maybe placed north-south, to maximize production in morning and evening when it's needed most.
jamescrowley
you also appear to get efficiency gains as vertical panels don’t get as hot - https://www.pv-magazine.com/2023/11/10/researchers-shed-ligh...
jillesvangurp
The article seems to be mostly about grid scale solar. Of course an increasing amount is private or domestic solar installed on e.g. building roofs or wherever there is space.
When cost drops low enough, any surface with any exposure to sunlight is in scope for installing solar on if it can yield more energy than the cost of installing solar on it. It stops being about what is the most efficient and starts being about if the surface is good enough to provide a decent return on investment. Maximizing that ROI is complex but it boils down to getting more value out of the installation than goes in.
Solar doesn't even have to be in panel form. Some office buildings now have windows that double for solar generation. A thin transparent coating does the job. There are roof tiles that double as solar panels. Aptera makes electric cars with integrated solar panels. These are curved glass panels that are manufactured to fit the profile of the roof and hood. It's also possible to print organic solar cells directly on plastic rolls. No glass involved. Or panels. Those are less efficient but you can integrate them on all sorts of surfaces. A lot of that stuff is still emerging technology. But especially organic solar printed on plastic rolls could end up being very cheap to produce. And very light.
Veserv
Domestic solar is a rapidly decreasing fraction of total solar deployments [1]. Not because it is not growing exponentially, but because grid-scale is much more exponential with no signs of that changing.
mapt
Grid scale solar benefits from bifacial cells in a vertical orientation just as much as home scale solar - it dramatically improves winter production and extends the production of the spring/fall day a few hours earlier and a few hours later.
mg794613
Not only does it increase overall production, currently one of our biggest challenanges is transport and distribution, and having some of that power in the of-hours instead has more benefits than power total alone.
turtlebits
Yep, but you're severely limited in terrain types. Unless you need the "fence" cover, I can't see it being worth it due the efficiency loss.
gorbypark
I’ve seen some YouTube videos of people making solar fences with bi-facial panels. If I recall correctly on the one I was watching, they were going for morning and evening production and faced them east/west. One side would get the morning light then the other the evening light.
Calwestjobs
(not sarcasm)
Yes ! Triple price of PV panels to buy "ceramic glass print" PV panel with eye pleasing pattern / stealthy photo on it and you can have facade or fence made from PV panels, there is drop in generated power from 10-50 % depended on pattern, color used.
Price per panel not price per install ! ! ! And subtract need to buy materials used for that purpose before.
rjsw
Balcony Solar is a thing, most of the panels will be vertical in that use case.
danielheath
It’s mentioned in the article that sunlight from near the horizon passes through a lot more atmosphere, which attenuates the light so much that you might as well not bother with the panels.
mapt
That depends on your latitude, how dear land is, and how close to breakeven your application is.
For a lot of applications, panels are so goddamn cheap now and breakeven happens so fast that "Just buy twice as many panels" is the best solution to any problem that doesn't involve land area. Winter production in a snowy/leafy climate at a latitude tilt, though, is the exception to the rule; Production is so impaired without regular maintenance that twice as many panels is not very helpful. But set those panels vertical, at a range of orientations, and snow/leaves stop being an issue, you get sizable exposure with the sun low on the horizon, the maintenance requirement goes away, and you get an appreciable amount of power earlier in the morning and later in the afternoon, you just don't get quite as much at noon.
adammarples
North South is exactly opposite of what you need, the sun is never north
gpm
I'm pretty sure by north-south they are talking about the direction the panel lies in, i.e. the faces point east/west.
But even under your interpretation, you aren't always right. If you're far-ish north of the equator you want south facing panels (and the reverse) and if the cells are cheap enough it makes sense for those panels to be bifacial, with one side permanently facing away from the sun, to get a bit of extra energy from ambient light. Especially in winter when there is less sun (so energy is at a premium), and highly reflective snow resulting in a lot of ambient light.
dylan604
what if you're in the southern hemisphere?
Someone
Then, you’re a statistical outlier that can be ignored in the analysis :-)
(Only about 12% of all humans live in the southern hemisphere)
adammarples
Genuinely didn't even consider this XD
kgermino
I’m pretty sure they mean that the width of the panel is north-south so faces are due east or west
xphos
One cool observation of an grid wide advantage is that single axis really normalize the power curve per panel. There are many reasons way more consistent production would be better.
I am curious if just having more fixed panels normalize production at scale
tappaseater
I'm probably not thinking this through, so go easy, but why wouldn't tracked panels also produce a normalized power curve? My assumption behind the question is that they follow the same track as Sol every day, which doesn't vary at least year-to-year.
tmjdev
I always see articles about the decreasing cost of solar, but where are these costs collected from? Is it just not available at a consumer level? Maybe I missed the sources in the article somewhat...
turtlebits
There are lots of consumer facing companies selling panels. You'll need to buy in bulk (generally a pallet), but you can easily get them for $0.30 / watt.
null
I 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.