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
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".
You have a simple motor that slowly tilts the array from facing East to facing West as power is being generated. The motor does not start until the panel is generating a certain amount of power. The motor runs at a fixed rate with a screw that takes about 7 hours to move the panel.
Once power stops (when the sun sets) weights on the opposite side slowly tilt the panel back to the starting position so it is ready for the next day.
I am curious if just having more fixed panels normalize production at scale
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.
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.
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.
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.
Space is cheaper than maintenance and breakdowns in many cases.
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
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.
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.
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.
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".
Crisis of 2008 made EU to think about resiliency so they asked all kinds of economists, physicist, other science people what should be done to provided that and one of those things implemented was building energy efficiency directive [https://energy.ec.europa.eu/topics/energy-efficiency/energy-...]
which progressively increased demands on building sector to provide citizens with "low energy" housing. and currently most states of EU have requirement to build houses where defacto energy need for yearly heating of a house is lower then energy yearly demand for hot water (hot ater can not be lowered significantly without heat pumps - COP3+)
Agreed - and guilty as charged which is why we're switching entirely to solar.
(I will also note that my household "cheats" by living in California where we need relatively little heat and do not even own an air conditioner so our path is, perhaps, a bit easier)
My main point is that whether you're a frugal EU council house or a profligate Texas McMansion, we - all of us - will continue to invent new demands for energy and continue to trend towards more energy used per person per unit time.
Therefore, if you're looking ahead to deployment of solar resources you should be realistic about that trendline.
" 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.
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.
netting? ha! thanks for the funny visual so early in the morning.
You want high tensile strength and some level of flexibility/elasticity to absorb the hailstone energy over a greater-than-zero distance. Or to shatter the hailstone well above the solar panel.
Probably too light-blocking to leave up continuously, and maybe awkward and failure-prone to deploy automatically.
So insurance is probably more cost-effective for most installations.
Just because your local car dealership(s) didn't opt for hail protection nets isn't on its own evidence for or against their effectiveness. There are a great many factors that go into such a decision and, unless you were privy to the decisionmaking process itself, whether or not nets were considered -- much less their effectiveness -- is pure speculation on your part.
The point I'm trying to make is just that there are a lot of off-the-shelf (or nearly so) hail protection strategies that seem like they might have better economics than single-axis-tracking installations, which might improve the cost effectiveness of a fixed panel installation to the point where, even in hail-prone regions, it might be doable.
To be clear: anti-hail nets are already a COTS product, just not for this application (as far as I'm aware). Nets are just really, really good at absorbing kinetic energy. I mean, that's effectively what kevlar ("bulletproof") vests are made of -- netting with a very small cell size. But it seems to me like some kind of roll-out kevlar or dyneema netting could be really effective at protecting panels, though I think you'd need some kind of better strategy for safely dispersing the hailstones after they were caught, so you don't end up with a huge collection of hailstones on the net.
I agree that there's probably too much light blocking to leave them up continuously, and I'd also be worried about UV damage. But remember that the comparison here is to single-axis-tracking installations; I think automatic deployment of anti-hail netting could easily be made at least as reliable as the tracking system, if not significantly more so. Maintenance and testing would also be very cheap in comparison, since you could do it at night (ie without affecting power production), and damage to the protection system could be repaired without taking panels offline.
The more I think about it, the more I'd be interested in seeing it deployed.
Nets are flexible. The energy of the collision goes into accelerating the net at the point of the collision. The net can quickly spread that energy into accelerating the surrounding areas of the net and so on. Unlike with a rigid cover this is not nearly instantaneous, so you don't have all the kinetic energy of the hail being poured into the net at once. That and the ability of the net to rapidly spread energy means that you don't get enough energy anywhere to break the net. It just stretches as it decelerates the hail.
You can see how this works by watching a soccer game and observing how the nets at the goals stop balls. Hailstones that weigh more than a soccer ball are extremely rare, as are hailstones that are falling faster than many strikes and penalty kicks in a professional soccer game, and you don't see many soccer balls breaking through the net.
People have calculated how fast a soccer ball would have to go to get through the net and found that it is over 220 mph. The largest recorded hailstone is estimated to have had a terminal velocity of 168 mph, based on size, mass, and atmospheric conditions. That hailstone had about 16% more kinetic energy than a 220 mph soccer ball and so might have broke the net, but soccer nets are by no means the strongest nets that can made. And remember that was the largest hailstone ever recorded--we are talking a once in decades event.
However, the bit where it’s talking about increasing the angle means creating gaps between panels or the shadowing is going to offset any gains while also requiring far more panels and more land at which point you might as just angle the panels based on latitude.
actually this is "bad kind of article", because there is so much information in there / "everything covered". that it is almost impossible to have comments about it lol.
Literally laying them flat on minimally cleared land would win the simulation. Fewer panels, fewer acres, less mounting hardware, less labor, more power. Real world conditions not included in the analysis, such as wholesale electricity prices over a day and land not being flat, drives a lot of these choices.
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
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.
The only reason I can see for added complexity is if you're space constrained, and in almost all cases, not cost efficient.
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.
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.
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.
> March 2024: Terraform completes the end to end demo, successfully producing fossil carbon free pipeline grade natural gas from sunlight and air.
If you take carbon from the air, mix in energy from the sun to turn it into a fuel, then burn the fuel (undoing the reaction), where is the pollution?
There's more efficient ways to solve the climate problem than to install ginormous amounts of gas production, like you can run a heat pump instead of creating methane from that energy, but it's a solution that'll please even the old farts (no pun intended)
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.
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.
The insane energy density of fossil fuels means this is an excellent “emergency” back-up plan should the sun not shine often enough.
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.
Merely a 10 watt panel in the Netherlands has been fine whilst camping for weeks, but obviously I have to severely compromise on modern life - 10 watts powers a lamp for a few hours in the evening and a phone charge each day.
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.
I’d never considered it latency but you’re right and it’s hilarious.
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.
I have some pretty graphs at https://shkspr.mobi/blog/2020/04/comparing-solar-panel-gener...
It's definitely the exception rather than the rule though.
Surely it is Rayleigh scattering that is important, not scattering off ozone?
rini17•2d ago
jamescrowley•17h ago
gorbypark•17h ago
danielheath•16h ago
mapt•11h ago
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.
jillesvangurp•15h ago
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.
mapt•15h ago
mg794613•13h ago
Veserv•9h ago
[1] https://news.ycombinator.com/item?id=42591918
derriz•1h ago
I don’t see the logic? As panel prices drop, installation costs start dominating overall cost of energy produced and so economic pressures will be on simpler and simpler PV installations. Laying a panel almost flat on the ground amongst thousands of others will be a cheaper process - both initially and in terms of ongoing maintenance - than anything that involves sending workers up ladders or cherrypickers attaching and wiring a panel onto the side of a building.
So grid scale will start to dominate over domestic or “novelty” (e.g. floating panels on reservoirs) and simpler and simpler approaches to installation (like removing tracking) will become attractive.
These effects are already apparent. Basically the opposite of what you’re predicting?
adammarples•15h ago
dylan604•13h ago
Someone•13h ago
(Only about 12% of all humans live in the southern hemisphere)
adammarples•11h ago
Dylan16807•3h ago
kgermino•12h ago
gpm•4h ago
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.
rjsw•14h ago
Calwestjobs•11h ago
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.
turtlebits•5h ago