[HN Gopher] The future of solar doesn't track the sun
___________________________________________________________________
The future of solar doesn't track the sun
Author : surprisetalk
Score : 102 points
Date : 2025-05-01 18:06 UTC (2 days ago)
(HTM) web link (terraformindustries.wordpress.com)
(TXT) w3m dump (terraformindustries.wordpress.com)
| rini17 wrote:
| 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 wrote:
| 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...
| gorbypark wrote:
| 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.
| danielheath wrote:
| 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 wrote:
| 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.
| jillesvangurp wrote:
| 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.
| mapt wrote:
| 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 wrote:
| 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.
| Veserv wrote:
| 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.
|
| [1] https://news.ycombinator.com/item?id=42591918
| adammarples wrote:
| North South is exactly opposite of what you need, the sun is
| never north
| dylan604 wrote:
| what if you're in the southern hemisphere?
| Someone wrote:
| 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 wrote:
| Genuinely didn't even consider this XD
| kgermino wrote:
| I'm pretty sure they mean that the width of the panel is
| north-south so faces are due east or west
| gpm wrote:
| 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.
| rjsw wrote:
| Balcony Solar is a thing, most of the panels will be vertical
| in that use case.
| Calwestjobs wrote:
| (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.
| turtlebits wrote:
| 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.
| weinzierl wrote:
| 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 wrote:
| 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.
| johnea wrote:
| 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".
| xphos wrote:
| 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 wrote:
| 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.
| GaggiX wrote:
| I think this has been common knowledge for a while now.
| PicassoCTs wrote:
| So, a sloped half cone is ideal if you have the space?
| Simulacra wrote:
| I thought this might be an article about a solar updraft tower,
| which also doesn't track the sun, or require solar panels.
| tgsovlerkhgsel wrote:
| 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.
| leoedin wrote:
| 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.
| yummypaint wrote:
| 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 wrote:
| 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.
| hinkley wrote:
| This has been my understanding as well. But on the plus
| side, while you may run a machine all day, the price of
| cooling your equipment varies with the outside
| temperature and that is highly correlated with available
| renewable power. The AC units and diesel backup power are
| systems you buy and prefer to have idle. But not your
| press or data center.
| WillPostForFood wrote:
| "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.
| philjohn wrote:
| 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.
| ceejayoz wrote:
| 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.
| Calwestjobs wrote:
| 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
| bbarnett wrote:
| 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 wrote:
| 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.
| rsync wrote:
| 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 wrote:
| 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 wrote:
| "Ordinary European household" will change even lower :
|
| 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+)
| Calwestjobs wrote:
| 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.
| Calwestjobs wrote:
| 50 degrees of latitude, north temperate zone, temperate
| climate,
| ac29 wrote:
| > 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.
| hinkley wrote:
| 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.
| nbadg wrote:
| Compelling analysis. But if hail damage is the primary concern,
| tracking seems like an X/Y solution. What about eg anti hail
| netting that can be rolled out when the weather forecast predicts
| hail? It seems to me like a middle ground might be automated
| deployment of hail protection, which by definition has lower aero
| loading than what amounts to a big semiconductor sail.
| dylan604 wrote:
| anti-hail netting? you must not be from somewhere that receives
| a lot of hail. hail punches through solid coverings at the
| right size. if it's not the right size, then it's not that
| damaging.
|
| netting? ha! thanks for the funny visual so early in the
| morning.
| jfengel wrote:
| Sorry, I don't get the joke. Nets can be pretty strong. Is it
| because there's a lot of hail at sizes big enough to do
| damage but too small for a net to catch without deep shadows?
| quesera wrote:
| I think a hail net would be feasible for some cases. Golf
| balls break solid coverings too (and windows, car roofs,
| etc), but we have nets for them.
|
| 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.
| medoc wrote:
| Anti-hail netting is definitely a thing (protecting cars or
| fruit trees), for the reasons you state. Even big
| hailstones are rather slower than fast golf balls.
| dylan604 wrote:
| Hail damage at car dealerships in my area is so expensive
| that the dealers have added coverings for the lots
| (pretty sure highly encouraged by the insurance
| companies), and they are most definitely not nets. Nets
| would have been cheaper, so that should say something
| about their effectiveness (or not)
| bbarnett wrote:
| Ascetically, nets get dirty and are hard to clean, have
| birds on them, things grow on them, and they look gaudy
| to some.
| nbadg wrote:
| Hail protection nets are a COTS product. Full stop.
| Properly-designed nets are exceptionally strong; that's
| why we make "bulletproof" vests out of them (that's all
| they are, just a fiber net with a very tight weave).
|
| 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.
| nbadg wrote:
| I agree with your implicit point that the key question is
| probably cost effectiveness compared with insurance.
| However, in the context of the OP, insurance premiums in
| hail-prone regions was listed as a prime reason why single-
| axis-tracking panel installations are, in some regions,
| probably still a better bet at grid scale.
|
| 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.
| tzs wrote:
| Hail punches through solid coverings because they are rigid.
| They nearly instantaneously stop the hail which means they
| absorb all of the kinetic energy of the hail very quickly.
| They don't have a good way to dissipate that energy as
| rapidly and it goes into breaking the structure of the
| covering.
|
| 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.
| Calwestjobs wrote:
| i used standard chain link fence on top of my small greenhouse
| and it works even with such big "holes", no mechanism, just
| manual labor but needs good forecast which can be issue.
| scotty79 wrote:
| I really like that how it's possible to put bifacial panels
| vertically along north-south direction to get solar power off
| peak. It should reduce cost of installation (it's basically
| multiple rows of fences), snow removal and cleaning. Washing down
| panels from dust could probably be automated too and if you build
| them up a bit higher you could have a meadow underneath or even a
| field of something. Hail should also be probably less of a
| concern. You need more land of course but it's still awesome.
| tmjdev wrote:
| 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 wrote:
| 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.
| Retric wrote:
| The article fees disingenuous, flat panels collect the maximum
| sunlight from a given area of land and require fewer panels than
| the arrangement shown. Angling them helps the rain wash them and
| reduces the amount of mounting brackets unless you're laying
| panels flat on the ground. Similarly total KW over the day isn't
| why tracking mounts are so common instead it's the increased
| value of electricity in the mornings and evenings so the actual
| economic benefits != total kWh.
|
| 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.
| Calwestjobs wrote:
| everything is addressed in that article.
|
| 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.
| Retric wrote:
| It's really not.
|
| 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.
| wyldfire wrote:
| The graphs show huge price drops over the last ten years. I
| wonder, how different does the price look for residential solar
| panel installations? Presumably the labor will start to dominate
| the cost if it doesn't already?
| ahartmetz wrote:
| Labor does dominate. Panels are dirt cheap and inverters, while
| they haven't come down in price that much, seem to still cost
| less than half of the price of the panels per watt.
| tzs wrote:
| 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
| bob1029 wrote:
| 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.
| turtlebits wrote:
| 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.
| mchannon wrote:
| 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.
| philjohn wrote:
| 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.
| mrshadowgoose wrote:
| 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.
| photochemsyn wrote:
| 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.
| mr_world wrote:
| How does using these the power from your panels to generate
| natural gas help solve climate change? Unlimited abundant natural
| gas sounds awful
| lucb1e wrote:
| Consider where that methane / natural gas is coming from. Their
| homepage says (with the world's most convoluted hyphen-omitting
| compound adjective, but basically see the last 6 words):
|
| > 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)
| adamcharnock wrote:
| 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.
| hx8 wrote:
| 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 wrote:
| 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 wrote:
| I'm not sure it's rare to live about 45degN, where we start
| to see >9 hours of sunlight in the winter. The intersection
| of places that are both above 45degN and very cloudy
| (Portland, Seattle, London, Detroit, Copenhagen, Dublin,
| Vancouver) or in high altitude is probably 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 wrote:
| What is the appeal of living off-grid?
| sneak wrote:
| 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.
| freehorse wrote:
| 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).
| edent wrote:
| 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...
| csr86 wrote:
| 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 wrote:
| 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.
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