Alternative to microinverters - Page 1
Forum section: electronics / general

author: cegue
author_rank: Newbie
timestamp: September 02, 2024, 01:04:19 pm
content: Hi, I want to start a personal project for my small countryside house. However, the lack of a similar product in the market is making me doubt its feasibility.The house is surrounded by trees, so shading is always present during the day. There’s no way to improve this by changing the panels’ layout. Thus, a parallel connection is necessary, and a friend suggested using microinverters. This is fine, but I already have an inverter and still want to use it. So, this idea came to mind:Why not create an isolated DC-DC converter to be placed on the back of each solar panel? The output of each converter would be >320V DC, and then the main inverter would transform it to 230V AC.Why doesn’t this product exist on the market? They would be cheaper and less complex than microinvertersEdit:Similar to this producthttps://www.ti.com/lit/ug/tidu404/tidu404.pdf

author: Siwastaja
author_rank: Super Contributor
timestamp: September 02, 2024, 02:03:11 pm
content: Quote from: cegue on September 02, 2024, 01:04:19 pmWat???QuoteThere already exists something much better: non-isolated DC-DC converters to be placed on the back of each panel, then those in series, together generating high enough voltage for the inverter, yet allowing separate MPPT control per each panel. These are called "optimizers" and are widely available.Microinverters or optimizer based system are both OK for your case.

author: Marco
author_rank: Super Contributor
timestamp: September 02, 2024, 02:03:50 pm
content: They're called power optimizers, but they are usually used with series connection (and I assume they just bypass under full illumination).For parallel they would have to be mandatory, with the serial solution they can be optional.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2024, 03:21:51 pm
content: Optimisers are one way, but you can also think about arranging the panels in groups which receive shading together. That is how I organised the system on my roof.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 02, 2024, 06:29:55 pm
content: Also worth considering:1) If shading affects most of the panels most of the day, consider not doing the install at all. Only in such case, microinverters/optimizers provide significant advantages over string inverter, but then again the system is more costly and still producing much less than a less obstructed system.2) If shading, at any point in time, only affects small number of the panels (e.g., significantly less than 50% of panel count), a string inverter could do surprisingly well: partial shading is not as big as a problem as microinverter sales folks say. Panels have bypass diodes: only the production of the shaded panel drops to zero, rest produce fully, this is what microinverter or optimizer sellers want to lie to you about to make their case.e.g. with 10 panels out of which 2 are shaded, string inverter produces 0.98*(8 * 100% + 2 * 0%)/10 = 78.4% of rated power, while microinverters produce like 0.95*(8*100% + 2*30%) = 81.7% of rated power. Not much of differenceeven ifyou had two panels out of ten shaded for the whole day! If you have partial shading for only an hour or so, you already lost your gains in lower efficiency of the micros.But if the shading affects many panels at the same time, then make sure the rest are capable of exceeding the inverter's minimum MPPT and minimum startup voltages, otherwise exactly what microinverter folks claim will actually happen. If like 5 out of 10 are shaded more than some half and hour or so, consider micros/optimizers or not doing it at all.If you have enough panels to satisfy two strings of a string inverter, then play the game as nctnico says. Then again if you are only barely able to exceed the minimum MPPT/startup voltages, then not dividing into two strings might be better after all.

author: tszaboo
author_rank: Super Contributor
timestamp: September 02, 2024, 06:35:43 pm
content: Quote from: cegue on September 02, 2024, 01:04:19 pmSolaredge uses DC-DC converters, called power optimizers. They are still connected in series, so all the POs share the same current, while voltage changes with the solar input.It works quite effectively, I have it on my roof.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2024, 07:19:46 pm
content: Quote from: Siwastaja on September 02, 2024, 06:29:55 pmI don't have exact numbers, but partial shading of only 1 panel influences the solar setup I have much more than the numbers you write above.I have the same inverter brand (Growatt) as this guy and I think the relative influence is similar:I'll try to post some numbers from my own inverter when there is some shading over the panels. But it could be the Growatt inverters are not good at dealing with shading.Anyway, if there are trees obstructing the solar panels, the best way is to trim the trees down a bit. Using optimisers or micro-inverters adds costs which can make a solar install un-economic quickly especially since many energy companies seems to be making it less economic to supply solar energy to the grid nowadays.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 03, 2024, 08:53:42 am
content: Quote from: nctnico on September 02, 2024, 07:19:46 pmThe key question is, does the string's (minus 1 panel) total MPPT voltage fall below inverter's minimum MPPT input voltage? This is what happens in a marginal design with minimum number panels per string. If not, then another explanation could be very poor MPPT tracking algorithm which gets stuck in local minimum, but I would be surprised to hear this still being a problem (unless your Growatt inverter is already pretty old. I don't remember all the model numbers and when they were introduced.)

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2024, 09:34:34 am
content: It is not a sunny day but covering a few cells makes the output power for that string go down to 355W from 480W. I also see the DC voltage going up for that string. In this particular situation it means a reduction of around 25%. The inverter is less than 2 years old.

author: tszaboo
author_rank: Super Contributor
timestamp: September 03, 2024, 11:04:49 am
content: Here is my production data for today. The panels below get a bit of shading, reducing their output. 11x360W system.The optimizers don't make the system more expensive, so IMHO it's worth it. You don't need DC isolator with these, and the inverter is cheaper than comparable inverters. When I bought the system, the optimizers were ~10% of the total system cost, including installation.Though it's never going to beat the price of a system with cheap chinese inverter and bottom of the line panels.Apparenly you can get panels now for 60 EUR, so get more panels.https://www.solar-outlet.nl/jinko-440wp-all-black-tiger-neo-n-type.html

author: Siwastaja
author_rank: Super Contributor
timestamp: September 03, 2024, 11:42:39 am
content: Quote from: tszaboo on September 03, 2024, 11:04:49 amNote this is only true in some particular region / market. Here no one buys optimizers, therefore it is hard to find installer for them, and they would likely increase the cost of the system by at least 30% and never pay back for themselves. Obviously, if you can get the deal you describe, it would be fool's errandnotto get them.

author: cegue
author_rank: Newbie
timestamp: September 03, 2024, 11:48:33 am
content: Thanks everyone for the clarifications.Yes, power optimizers look like a solution, and probably it would be the best one in my case.But in general, would not it better to have isolated DCDC converters? Parallel connection, with every PV panel having a converter, stepping up the voltage to >320V and then a central inverter.I can only see benefits over series connection with optimizers or microinverters...- PV panels are isolated from HV, hence less risk of shock if there are cracks- Reduced wire gauge from PV panels to the central inverter- The inverter does not require step up stage, hence less complex- If one PV panel breaks or is shutting down for maintenance, the rest can continue workingWhy this solution has not been adopted in the industry??

author: tszaboo
author_rank: Super Contributor
timestamp: September 03, 2024, 12:02:44 pm
content: Because for parrallel connection you need twice the amount of wiring than in series. And standard wire thickness is wasted there.Panels breaking is a non-issue. You have maybe a week downtime in 25 years.The inverter doesn't require a step up stage with solaredge either.I don't think that power optimizers are going to be economical for the future. 2 MPPT input microinverters, like the Hoymilles HMS-2000-4T make them obsolete. It accepts 4 panels. It has 2x MPPT, so shading losses are a good compromise, and it's very very cheap.The whole solar industry is just trying to get a good compromise. There will be always better systems, but if they aren't economic ...

author: Siwastaja
author_rank: Super Contributor
timestamp: September 03, 2024, 12:06:04 pm
content: Quote from: tszaboo on September 03, 2024, 12:02:44 pmYeah, plus also classic "string inverters" having larger number of MPPT inputs and lower minimum MPPT voltages than before. You can get a small one with 2-3 MPPT inputs and 150V min voltage, that is pretty close to what microinverters have to offer already, so the gap is smaller than before (e.g. 1 MPPT input and 200V min voltage).E.g. my older inverter really requires 12 panels to work well. Nowadays a 8-9-panel system is possible with nearly every string inverter and some are happy with 6.

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2024, 02:04:20 pm
content: Modern solar panels also have higher output power (due to bigger sizes and improved efficiency) so you need less panels for more power. In my install I have 2 strings with 6 panels each which add up to 4500Wp. The 4.2kW inverter I have has an MPPT range starting from 80V. So it would be happy with 3 to 4 panels. From what I've seen from micro-inverters is that many can't handle the maximum power of the solar panels unless you buy the really expensive ones. In my case that matters because my roof has a near perfect angle and orientation.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 03, 2024, 04:25:27 pm
content: Quote from: nctnico on September 03, 2024, 02:04:20 pmThis is an interesting note, because microinverters are marketed with the idea they will give the highest possible output over the wider operational area than string inverters (e.g., insolation differences). Yet if you get a 400W microinverter for a 400W panel, you will be flattening out the production during better-than-rated conditions and these conditions do exist in real world maybe up to +25% of rated, basically the case of partially cloudy day, combined full direct sunlight + indirect light from light clouds, maybe boosted by cold temperature.It's not ahugeloss for annual total production but microinverters are marketed by the very idea they extract the every last drop of what is available. Which is also why the 2-3 percentage point worse efficiency is kind of a problem IMHO.

author: max_torque
author_rank: Super Contributor
timestamp: September 03, 2024, 05:20:21 pm
content: Given the huge fall in costs of solar panels recently (such that for my system, the mounting rails and bracketry cost MORE than the panels themselves!!) the first priority is simply to fit every single square mm of space with panels, ie buy more panels not more optimisers!The second point is imo, if you array is roof mounted and therefore diffcult to access, putting active electronics in this environment is a false gain. Any failure here is going to hint you hard finanically speaking because of the effort required to replace parts up their (esp true these days in countries with strong HSE rules for "working at height")

author: Someone
author_rank: Super Contributor
timestamp: September 03, 2024, 10:46:36 pm
content: Chasing the last few percent is usually uneconomic:https://www.nrgsolar.com.au/blog/enphase-fronius-testing-stationwhich takes you to:

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 10:05:18 am
content: Quote from: Siwastaja on September 03, 2024, 04:25:27 pmIn my opinion micro-inverters make no sense at all. In every scenario they are more expensive compared to a string inverter. And when you oversize the string inverter (as mentioned in the video Someone linked to), you can get the little extra on a cold (say 10 degrees C) sunny spring / fall day. Going one or two steps up for a string inverter costs like 50 to 100 euro extra for the entire install.For micro-inverters the prices easely double. For example: the cheapest Enphase micro-inverter I can find at the shop I bought my solar gear from costs about 63 euro and can handle 295W. So that would add up to 756 euro / 3540W for my installation. The 380W micro-inverter costs a whopping 125 euro which would add up to 1500 euro / 4560W. And for Enphase you'd need to buy their control box and relay (which I've seen burned out; from looking at the board, the voltage rating is a tad low on the protection components).In comparison: a 5kW, single phase inverter costs 539 euro (including an option to connect batteries to it). The 5kW inverter would really take every bit of power from my solar panels as they can produce around 5kW on a sunny spring / fall day. The panels rated for 375W deliver around 417W in that situation (11% more than rated). Then again, it does cost extra and the question is whether it is worth it. After all, every bit of money you spend on the solar installation eats into the ROI.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 10:40:50 am
content: Quote from: nctnico on September 04, 2024, 10:05:18 amUntil a single solar panel malfunctions, you get 0 output and you have to go up to the roof to replace it or let a company replace it and you are directly break even on the costs of the company replacing a single panel.It makes perfect sense, there is not a single point of failure anymore and you can wait till a couple panels have broken down.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 04, 2024, 10:51:10 am
content: Quote from: Kjelt on September 04, 2024, 10:40:50 amSo why are not cars equipped with ten parallel tires on each axle so that you don't need to stop and change tires if one blows? I will answer that myself: because that would reduce efficiency, add cost, and tire failures are rare enough that replacements are a better option than redundancy. Or why only server PCs have dual power supplies, but ones used at offices (still doing work that matters) not?Engineering needs numbers and analysis, and that is why larger strings win in all professional installations, and microinverters are only sold to households where they can be explained by oversimplified "common sense", and often outright lies.And don't get me wrong, there is still potential in microinverters; distributed over centralized isoftena good choice, but it's all about spot-on engineering. The situation changes as soon as an "AC panel" is available i.e., a pre-wired panel + microinverter, with easy to install AC wire harness systems (plug and play like MC4 is supposed to be), which costsat mostthe same as equivalent string inverter system. But so far the microinverter manufacturers seem to struggle even supplying legal, safe and up-to-date with power ratings products. It's not a nice market to be in, some fundamental design paradigm shift is needed to make it work: for example the "AC panel" plus "safe AC plug" concepts, avoiding the electrician on the roof.Quote from: nctnico on September 04, 2024, 10:05:18 amIt seems microinverter manufacturers have not kept up with the trend of increasing panel size, efficiency and thus higher output power. 63 euros sounds appealing, until you realize 295W maximum power is suitable for a 270W or so rated power panel, which is ten years old technology. Youmightbe able to find a good deal of some new old stock on such ancient panels, but... Probably better just to buy modern stuff.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 11:07:50 am
content: Quote from: Kjelt on September 04, 2024, 10:40:50 amIt doesn't have to be. I have made my installation so that I can service all electrical connections to and between the solar panels from the windows in the roof. If 1 panel fails, I can disconnect it and bridge it if I want to. But that is a perk of how I did my installation.More realistically, a micro-inverter has a lot more components in it (and subjected to a very harsh environment) compared to a solar panel which is mainly a passive element. There is probably a 10 to 1 chance a micro inverter breaks before a solar panel does. You also need to consider what could cause breakage. In case of a solar panel breakage, this is likely a weather related event which is covered under insurance so replacing a solar panel wouldn't be super costly. I'd be more worried about sourcing a panel of the same size as panels seem to get bigger and bigger.Quote from: Siwastaja on September 04, 2024, 10:51:10 amThis would only work if solar panels are part of the roof and money is saved on roofing material. IOW: A dual use solution. So far the track record of such systems isn't great. In case of fire, the fire brigade can't get under the roof to put the fire out. There have been some serious incidents in the NL with such systems causing way more damage than necessary. Another problem is long term availability of replacement roofing material. Roof tile size & shapes (clay or concrete based) are pretty much standarised and you can still buy the correct tiles for homes built 60 years (or longer) ago.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2024, 11:13:55 am
content: Quote from: Kjelt on September 04, 2024, 10:40:50 amBut more hardware ( microinverters) means more potential failure points.How often do panels go bad ?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2024, 11:18:24 am
content: Quote from: cegue on September 02, 2024, 01:04:19 pmFYI there are a number of cheap inverter "back-end" PCBs on Aliexpress that can do the DC-AC conversion if you want to persue this :https://www.aliexpress.com/item/4001030294883.html?spm=a2g0o.order_list.order_list_main.225.1ece1802XhFtR8https://www.aliexpress.com/item/1005005448265485.html?spm=a2g0o.order_list.order_list_main.230.1ece1802XhFtR8https://www.aliexpress.com/item/1005001937739215.html?spm=a2g0o.order_list.order_list_main.236.1ece1802XhFtR8Most seem to be based on this fairly well-dcoumented controllerhttps://www.aliexpress.com/item/1005006160607383.htmlhttps://server4.eca.ir/eshop/000/EGS002/EGS002_inverter_digitale_a_onda_sinusoidale_pura_1.pdf

author: Siwastaja
author_rank: Super Contributor
timestamp: September 04, 2024, 11:23:27 am
content: Quote from: nctnico on September 04, 2024, 11:07:50 amYeah, and this is not just like idle talk. Surprisingly good reliability of PV panels is well known, and so is the fact that microinverters do fail and are harder to replace than the string inverter. Probably someone like Someone comes up with a good reference again as I fail to deliver.The argument is that production does not go to zero when either a panel or inverter fails. But what now, you are being sold a system which has higher likelihood of failure (just with smaller consequence), are you supposed to then just live with 90% of the production you used to have for the rest of the system lifetime? No way, of course you will replace the broken panel or broken inverter. So why push it further in the future, obviously you want to fix it ASAP to get back to full production. But then again grid tied PV generation is not mission critical that say 2 weeks of downtime with MTBF of say 50 years would be any kind of problem. You have such "downtime" regularly anyway due to dark, cloudy weather. So what you lose in a string inverter is minimal anyway.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2024, 11:24:54 am
content: Quote from: cegue on September 03, 2024, 11:48:33 amWhy isolated ? Conventional series systems have HVDC on the cabling, so no real safety advantage, and added cost. Just isolate at the inverter.

author: Someone
author_rank: Super Contributor
timestamp: September 04, 2024, 11:24:59 am
content: Quote from: mikeselectricstuff on September 04, 2024, 11:13:55 amHow often does a panelandits integrated bypass diodes go bad at the same time? Either could fail and you'd still not get 0 output from the string (as the linked video shows).

author: Marco
author_rank: Super Contributor
timestamp: September 04, 2024, 12:00:11 pm
content: Quote from: cegue on September 03, 2024, 11:48:33 amAs I said, optimizers are optional. In a parallel system they would be mandatory, the small advantages probably don't justify an entirely separate product line.It would minimize leakage currents and simplify the inverter, still not worth it.

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2024, 01:43:07 pm
content: Quote from: Someone on September 03, 2024, 10:46:36 pmYou get piece of mind, and a higher efficiency system.It's well known that the marketing claims by Enphase or Solaredge are not true. They are made by marketing after all.When I was buying my system, I paid 1:3 for the panels to the optimizers. More realistically, if you include the racking and the installer's cost (they base it on the number of panels). Plus as I said, the Solaredge inverters are cheaper compared to SMA or Fronius. Not compared to the bottom shelf inverters. So the extra cost in the end is that much.Now this ratio is closer to 1.5:1, I wouldn't install this system.And if you are only about the ROI, there are used systems on the market for next to nothing (here).For example a 16x270W system with a 4KW inverter is for sale for 500 EUR. The ROI of that is probably less than a year.Tigo also makes optimizers that work with regular inverters, and as I understand you can just place it on some of the panels.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 02:46:31 pm
content: Quote from: Siwastaja on September 04, 2024, 10:51:10 amMicroinverters do not reduce efficiency, esp in a three phase setup.Add cost yes as said more expensive but gives additional benefits.Rare yes but very unpleasant when occurs as any modern car driver will ackknowledge when he stands beside the road and the spare wheel was replaced by a shitty foam can or even nothing.For companies, cost matter but reliability should also matter, depending on the cost / benefit you can make your decision.My panels are unreachable at 12m height on a tilted roof for normal persons and require special equipment or human acrobats with life insurance to service. One of the reasons I choose the microinverters.If someone else has a flat roof and is EE they might make another choice.Another benefit of microinverters is that you can add panels if you want, no need for a bigger inverter.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 02:50:24 pm
content: Quote from: nctnico on September 04, 2024, 11:07:50 amIndeed depending on the circumstances of the installation and the skills of the owner, different choices might be made.For teliability I get 25 years warranty on my microinverters but only 15 on the panel which also degrades over time.Indeed weather and accidents out of the equation you still would think the microinverter would die before the panel however that is also guaranteed incl workmanship just as a weather event. Although I already saw insurance policies where solar installations are excluded for certain events.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 02:55:15 pm
content: Quote from: Siwastaja on September 04, 2024, 11:23:27 amThen why do my microinverters have a almostvtwice longer guarantee than any normal inverter?Could it perhaps be that in countraey to normal inverters they do not use electrolytic capacitors which are known to degrade and are one of the first components to die in any electronic circuit? Could it be it only has to take care of a few hundreds Watts max and mostly less, while the normal inverter has to handle kWs?Lets see how it plays out, I will post back in 8 years when the first ten years have passed and in 18 years. In the mean time my two neighbours have the same company install their systems with normal inverters , not statiscally relevant but still interesting to see who gets the first problems.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 03:00:59 pm
content: Quote from: Kjelt on September 04, 2024, 02:55:15 pmActually the lifespan of an inverter doesn't really matter. 10 years is good enough. If you want to add batteries for example, then you'll need to either pay for an extra inverter for the batteries OR replace the existing inverter with a hybrid one. With micro-inverters you'll always need to invest in an extra inverter for batteries with the additional efficiency reduction as you'll need to convert between AC and DC twice. And with micro-inverters you are stuck with old technology long before the solar panels are due for a replacement.The shop I bought my solar installation from less than 2 years ago only sells the hybrid version for the inverter I have nowadays. And they are cheaper compared to the inverter I have as well. Either way, by the time an inverter needs to be replaced due to a failure, you likely want to upgrade anyway.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 03:43:26 pm
content: Batteries is aagain a new parameter to the equation. The economic justification for those in our country makes 0 sense even if you build them yourself from server batteries, in which case the bms and charger/ inverter are probably also from the same brand.But then you can also charge the batteries from mains in combination with a dynamic energy contract making it even more versatile than charging from your own solar. (Again a new parameter which does not help the discussion).

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2024, 04:01:35 pm
content: Quote from: Kjelt on September 04, 2024, 03:43:26 pmI was calculating that a battery system at home makes electricity more expensive than not having it. Because of the charging-discharging efficiency loss, you use more electricity. And gain nothing.These new cartel made extra solar charges are that stupid.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 04, 2024, 04:49:08 pm
content: Quote from: Kjelt on September 04, 2024, 02:55:15 pmExactly because the guarantee is the only way for the manufacturers to manage the reputation hit from earlier reliability problems that are too widely known. It doesn't even matter if the problems are that widespread, but people know about them so they have to offer guarantee.The cost of the microinverter itself being negligible, the key question is, does the guarantee of the inverter cover the replacement work? Or does the installer or sales company need to provide such extra guarantee with their own risk?QuoteThis is totally absurd. You have no idea what you are talking about.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 04, 2024, 04:58:27 pm
content: Quote from: tszaboo on September 04, 2024, 04:01:35 pmOf course you can gain savings, but return of investment is still nearly impossible. Exact details depend on country and types of contracts available, but usually self-storage of generated solar makes money because for selling PV out to grid, price you get from it is much worse compared to when you buy the electricity back in the evening/night/morning. For example, here you can buy for spot price plus transmission plus taxes, but sell for only the spot price minus margin. E.g. buy at 15 cents/kWh, sell at 8 cents/kWh.Further money can be made in spot markets / hourly pricing. Buy when cheap, self-use when more expensive. In extreme cases, sell to grid.But all this requires careful optimization, and even if you do it right you can make say 200, maybe 300 EUR/year with a 10000EUR investment with a guarantee of 8 years.And yet, this is what people want. Battery business is growing hugely and now more than 50% of our new customers are buying our box because it does said battery optimization. We would like to see our box bought primarily to control those hot water boilers, EVs and so on, it makes roughly the same 200-300 EUR/year for one fifth of the investment. Luckily, many of our battery customersalsohave something else to control.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 05:04:36 pm
content: Quote from: Siwastaja on September 04, 2024, 04:49:08 pmIndeed I have to take that back it was in my memory that they did not use electrolytics. But by reviewing some teardowns they do indeed, although only four pieces.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 05:05:22 pm
content: Quote from: Kjelt on September 04, 2024, 03:43:26 pmThat is true for today. But that may change completely a few years down the road. Building some flexibility into your energy system makes sure you can adapt and don't overspend at the start. That is also why I pinched every penny when doing my solar panel installation to make the sure the time until it has paid for itself is no longer than 4 years. Any longer just doesn't make sense due to all the economic uncertainties (including unforeseen breakdowns). And to be honest, I don't think I'm going to achieve break-even within 4 years due to tariff changes.

author: Marco
author_rank: Super Contributor
timestamp: September 04, 2024, 05:55:19 pm
content: I think government should set some standards and protocols in time to let batteries be used collectively.Otherwise people who got their batteries late are going to get screwed just like late adopters of PV, cost of power will inevitably shift from kWh to fixed connection costs. If the power companies can take a long term contract to take control over the home batteries, they can provide some ROI while needing to build less batteries of their own.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 06:00:38 pm
content: At this moment I'm not sure domestic / home batteries will ever be viable. In the end you can't beat the economics of doing something on a large scale. Also the energy grid is still organised to go from large producers to many small consumers. A large scale storage system fits much better within the existing infrastructure compared to a decentralised, fragmented system.In the Netherlands they are working on huge battery storage systems with capacities in the ballpark of 1 GWh -each-. Based on what I'v read in the news, these systems' storage cost are at little below 4 euro-cents per kWh and they get a major discount on transport costs. As a comparison: the cheapest 5kWh home-battery I found so far sits at 10 euro-cents per kWh stored. With my current electricity prices, I pay the utility company around 10 eurocents per kWh to use the grid as a battery (if I ignore the existing subsidies for a moment).Ofcourse you could speculate on electricity prices going negative and try to make batteries pay for themselves that way but big companies are better at playing that game. Recently I got an offer to spend 5k euro on a 5kWh battery pack (which is twice the price compared to a battery pack I found elsewhere) and the seller says it pays for itself in 5 years but I don't see that happening. It is a massive gamble and very unlikely to break even. An investment fund will be more likely to deliver a positive ROI during the same time.

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2024, 06:40:50 pm
content: Quote from: Marco on September 04, 2024, 05:55:19 pmSure sure, but then don't you already see that every single one of our governments are just puppets to the energy providers?I mean Enexis makes a Billion EURprofitin 2022, and then increases the prices because the network capacity is insufficient.They only serve 2.8 Million houses. So 360 EUR per household. For making sure that a bunch of wires don't break*. (euphemism)Don't expect that you will get a good deal for home batteries. They have profit targets to reach.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2024, 07:27:26 pm
content: The plummetting cost of panels makes microinverters seem excessively expensive. I can buy a 400W panel for £60, an Enphase IQ8 (that can't even handle 400W) costs twice that.

author: Kjelt
author_rank: Super Contributor
timestamp: September 04, 2024, 08:30:22 pm
content: Quote from: mikeselectricstuff on September 04, 2024, 07:27:26 pmTrue prices plummeted here because the rules were changed here. If you own solar panels you have to pay monthly to your energy provider, which was not the case before. Now nobody buys solar panels anymore and fourteen installer companies that I know of went bellyup.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 08:57:10 pm
content: Quote from: tszaboo on September 04, 2024, 06:40:50 pmThis reasoning & ranting gets tiresome. You forget to mention Enexis made barely any profit in the years before and after. The billion euro profit is a one-time exception. Probably due to selling off something. And all of their shareholders are provinces and cities / villages. So all the money they make flows back into public funds.

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2024, 09:18:11 pm
content: Quote from: Kjelt on September 04, 2024, 08:30:22 pmAlso, somehow every single supplier changed the rules, somehow the same time. And customer protection ACM just stands by, and shakes their head, "yeah, this is fine. Let's charge 2 million solar installation about 30 EUR a month". But there is no cartel and no interference according to nctnico./rant off.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2024, 10:47:15 pm
content: Quote from: Kjelt on September 04, 2024, 08:30:22 pmIf you own panels, or if only you export?

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 10:51:13 pm
content: Quote from: mikeselectricstuff on September 04, 2024, 10:47:15 pmOnly if you export and typically depending on how much you export. But this is supposed to stop when the subsidies stop. The energy companies basically found a loop-hole to recoup some of the money for the subsidies they have to contribute to. Another effect is that electricity prices have been made lower which is a double whammy for solar panel owners.To add some numbers:I used to pay 26ct/kWh and get 26ct/kWh for what I supply to the grid. So 4000kWh/year would make me 1040 euro/year (either by using directly or supplying to the grid). With the new tarif system, I pay (approx) 22ct per kWh and also get 22ct per kWh, so I would still make 880 euro/year. However, due to supplying around 2500kWh/year back to the grid, I need to pay a fee around 240 euro. So the 'profit' from the solar panels went from 1040 euro / year to 640 / year.

author: nctnico
author_rank: Super Contributor
timestamp: September 09, 2024, 01:44:42 pm
content: Quote from: nctnico on September 03, 2024, 09:34:34 amTo get back to shading losses. On my Growatt inverter I see output drops to over 30% when only a few cells are shaded. According to the seller, Growatt inverters don't have any shading optimisation in them. The alternative is to add optimisers.I also checked some other brands from the same seller but it seems shadow optimisation is not very standard in the inverter brands they are carrying.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 09, 2024, 03:08:26 pm
content: Quote from: nctnico on September 04, 2024, 10:51:13 pmSo did I understand correctly - for you, value of sell-to-grid is 640 / 4000 = 16 cents/kWh, and value of self-use is, as always, equivalent to buying price, that is 22 cents/kWh.So "having to sell" would lose 27% of the value compared to self-use.This doesn't sound bad to me at all, just understandable and fair. Say you are a nuclear plant or a coal power operator. It's not like you get paid for the final customer price either; there is value added in the chain, producer always gets less.Here we don't have such weird "first someone gives you too much credit for something then you have to return part of it" system, but the difference between buy/sell results in from having electricity bill consist of two different parts, paid to two different companies: energy itself which you can buy from multitude of providers, and transmission/grid fee which you have to pay to your local grid company. When you sell excess production to grid, you sell theenergyto the energy company of your choice, hence get paid for energy, but you do not get the transmission fee; which is understandable, because transmission fee is meant to cover for the costs of maintaining the grid and distribution.Here energy companies only accept to buy your excess production with spot price terms, which means that often the price you get from the excess is near zero. But many/most people find it somehow still feels like a fair system because it's all based on free market operating, on understandable terms. After all, if you need to sell for zero energy cost, you are also allowed to buy for zero! So this motivates people to (1) time the use of their energy, (2) increase self-use of PV, both very good things. At least much better than complaining about conspiracies as some others do.But I understand that your NL case where you are first subsidized and then penalized feels stupid and wrong. Similar to our system where EVs are free from one type of car taxation, but then have another EV-specific extra tax so that the end result is close to normal ICE taxation. It feels stupid as hell.

author: Electrodynamic
author_rank: Regular Contributor
timestamp: September 19, 2024, 04:24:29 pm
content: SiwastajaQuoteIt doesn't sound bad at all and I have designed and tested some island mode micro grids which could never touch 16 cents/kWh. One kilowatt equals 1.34 HP, so it's similar to running a 3hp genset at 70% power 24/7. I'm also testing a new CHP (combined heat and power) unit this winter and I would be very lucky to break even with maintenance and fuel versus power production. Of course, the bonus of CHP is that even if we break even on fuel vs power we still get the heat for free which is nice for cold climates like Canada.For perspective, the average off peak pool/producer price here in the last 24 hours was $20/MW or 2 cents per kWh. One kWh is equivalent to the average person on a peddle bike generator peddling flat out for 5 hours. So to an Engineer designing micro power generation systems 2 cents per kWh sounds like a miracle. At $0.02/kWh the payback period for a $1000 1kW grid tie solar setup would be 33 years. However the solar panels are losing 1% efficiency per year so the real payback period would exceed 40 years.So I think it's important to understand no residential system is ever going to compete with power generation on an industrial scale. The only real benefit of a solar power system is independence, security and power production at the point of use or off grid.

author: nctnico
author_rank: Super Contributor
timestamp: September 19, 2024, 05:37:20 pm
content: Quote from: Electrodynamic on September 19, 2024, 04:24:29 pmI think you have a good point here. The way I start to see it is that residential solar is more like a temporary 'thing' to get more renewable energy while waiting for nuclear and large scale solar + hydrogen to catch up. Home (battery) storage is already at a point it won't make any sense real soon because many companies are building large scale batteries nowadays and hydrogen based storage is around the corner. There is no way to compete with that as an individual home owner.

author: Marco
author_rank: Super Contributor
timestamp: September 19, 2024, 10:00:46 pm
content: That depends on how much monopoly rent they can get away with charging. They can get so greedy home hydrogen storage could become cheaper.

author: Someone
author_rank: Super Contributor
timestamp: September 19, 2024, 10:40:06 pm
content: Quote from: Electrodynamic on September 19, 2024, 04:24:29 pmOh dear, not that one again:https://www.eevblog.com/forum/chat/a-possible-way-to-keep-your-fridge-cold-in-long-term-blackouts/msg4245910/#msg4245910Average person wouldn't even get 1/3rd of that.

author: thm_w
author_rank: Super Contributor
timestamp: September 20, 2024, 01:00:42 am
content: Quote from: Someone on September 19, 2024, 10:40:06 pmFlat out means as fast or as hard as possible, maximum effort.Its implied that you can't maintain maximum effort for more than 30-60s.

author: Someone
author_rank: Super Contributor
timestamp: September 20, 2024, 04:14:08 am
content: Quote from: thm_w on September 20, 2024, 01:00:42 amWhen neither of those data points lie at an intersection or asymptote, how could it be implied?average person flat out > 200W, nothing adds up.

author: tszaboo
author_rank: Super Contributor
timestamp: September 20, 2024, 10:16:57 am
content: Quote from: nctnico on September 19, 2024, 05:37:20 pmI genuinely have no idea why suddenly home energy storage is being viewed as a green alternative, on a global scale, as a solution.Dave's installation is a prime example, he barely uses a few dozen percent per day, once. It's not efficient usage of batteries.The same batteries used in a device on utility scale could be sized to charge and discharge several times in a day and serve several households.How are home consumers supposed to use their battery effectively? You are charged full price to charge it, and fraction of it to discharge it. Taxed both ways. Meanwhile on utility level you are charged for spot price, which might be negative.It seems to be there is this brief window in this few years, that home battery makes sense, because once utility scale will catch up it's over. And why wouldn't they, there is money to be made on the market. Battery prices drop, new technologies like Na-Ion batteries are going to cost 1/3rd of current systems. And then there are the open cycle batteries that are more like a fuel cell, that are impossible to do at home, and infinitely scalable otherwise.I mean if you can make some money in this brief period, good, go for it.But to set it up as a policy, big advertisement campaigns, and greenwashing?

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 10:28:50 am
content: Quote from: tszaboo on September 20, 2024, 10:16:57 amI wholeheartedly agree. 99% of home battery installs are probably crippled like this, running small DoD% and small number of cycles per day. In Finland for example they sit 3 months disabled, during which the need for grid load balancing within the day is very real, and you can also get some very real money out of it.But no, expensive high tech sits unused in most homes.This is also exactly why our control box gets sold and installed... but it's still niche. We have surprisingly few competitors and most of the batteries are sold without any smart control, just for PV timeshift.I mean, evenwithsmart controls it is very hard to have batteries make financial sense. So our first simple algorithm reduced the payback time from 100 years to 50 years, and we are hoping the next better algorithm I'm working on gets that in range of 20-30 years. Then if we are able to sell our customers into reserve markets of frequency markets, itmightbe able toalmostmake financial sense, but...As I always say, there are better low-hanging fruits. Like controlling EV charging and electric heating/hot water on/off based on those same market mechanisms one controls battery with. You can't export (sell to grid) but financially sane sell events are pretty rare anyway and make a small, maybe single-digit % of total. Juggling the timing of "self-use of PV" vs. "import" vs. "self-use of imported" is equally possible with aforementioned simple loads (even just relay control), you don't need a 5000-10000 EUR battery to do that.

author: Zucca
author_rank: Unknown
timestamp: September 20, 2024, 01:33:46 pm
content: https://www.victronenergy.com/live/ess:start(last featurehttps://www.victronenergy.com/live/drafts:dynamic_ess)I installed it in my home since Jan 2024. I could not find any solar company here in US which understood what I wanted, so I hired the first one who did the monkey job to put the solar panel up and bring the wires down.I wired up the system myself basically.Battery: 42Kwh, 48V (LiFePO4 cells, bought directly from china)Inverters power: 16KWh (40KWh peak)Solar peak power: 14KWhInverters take 48VDC and feed the home.Solar panels goes to MPPTs (only DC to DC) and generate the 48VDC which feed the inverters and the excess power goes to the battery (first Kirkoff law at 48VDC bus bars).If batteries are full, MPPTs reduce output to match the power needed by the inverters (happens 3 times a month, in average). If batteries are <10%SOC the system switch to grid automagically.I am a happy camper.Goals achieved:- No bent over and sell energy for cheap (50%-60% $ loss each KWh) to (greedy) power companies- Grid is my emergency generator, 0dBa! and religiously maintained for me for only 12.5$/month (base price my contract)- More independence from the grid and outside world, 42Kwh UPS for the entire home, best case.- No extra costs for bidirectional meter installation (both one time at installation and increase monthly base price) [which piss me immensely off, for the power companies the bidirectional meter activation is just a mouse click]- No more arguing about safely interconnect my system to the grid- I can put as many solar panels I want, and the power company can't say anything and/or deny the interconnect (for them I still am a strange passive customer, who pulls 0KWh from the grid for long times)I use the batteries 10-100 %SoC.Don't know about the green solution, it could be.I just did it because it made sense in my head, and ROI is about 10-15years.I can only suggest Victron systems, they are a joy to work with and very very reliable. Worth every penny.uinverters? They make sense only in partial shade conditions, otherwise in my planet they are just a quick and dirty solution to generate solar powers.PS: I will never trust a power electronic device which is cooking at high temp on the roof everyday. No matter how good the design is, it is just simply not the smartest idea IMHO.

author: tszaboo
author_rank: Super Contributor
timestamp: September 20, 2024, 01:45:40 pm
content: Quote from: Zucca on September 20, 2024, 01:33:46 pmThe situation is very different in different parts of the world.- I pay 3x the connection cost as you, 26 EUR/month.- We had 3 power outage that were longer than 1 minute since my meter was installed, which is IDK 10 years now? 2 was scheduled in advance. 99.9999% reliability easily.- Bidirectional meter installed by default.- My solar system was accepted after I paid 50 EUR for the installer to take care of the paperwork, cause laziness. I could have done it for free probably.And here is the bottom line: Why do you have to install a home battery? Because grid is unreliable and bureaucracy is bad.Both of which should be solved with pitchforks and torches, not with a battery.

author: Zucca
author_rank: Unknown
timestamp: September 20, 2024, 01:52:30 pm
content: Quote from: tszaboo on September 20, 2024, 01:45:40 pmand third because my power companies interconnect rules/conditions were a joke and basically my solar panels would have made just more profit for them....The above make my blood pressure peaks high every time I think about it.Somepower companies are using the solar panels horse just to increase profit, and milking the cows customers even more. Every day.EDIT: Ah I forgot to mention that in a regular solar system, if the grid goes off the solar panels needs to be turned off as well for safety.No thanks, I wanna use the energy the sun is giving me. Especially when the grid goes bananas.

author: Electrodynamic
author_rank: Regular Contributor
timestamp: September 20, 2024, 03:23:55 pm
content: tszabooQuoteThe smart grid solves this problem and there are already companies that provide grid management solutions. In effect, one company manages tens of thousands of individual producers like Dave's installation over the internet. All the installations combined could produce hundreds of MW of power or more in minutes and is considered a utility scale producer the same as any other. The only difference is that this smart utility system is decentralized.In fact, I heard some people were making $200 a day using there EV and house battery to store power off peak and export it during peak hours. For example, yesterday I saw the pool price for power here change from $0.5/MW to $125/MW during the day. In some extreme cases the pool prices changed by $1000/MW in a matter of hours. So the grid is anything but stable and there is lots of money to be made using battery storage.

author: nctnico
author_rank: Super Contributor
timestamp: September 20, 2024, 03:35:48 pm
content: Quote from: Electrodynamic on September 20, 2024, 03:23:55 pmThis may be the case right now but if there is a profit to be made, this will attract big investors going for large scale solutions. In the end a decentralized solution will be more expensive and thus it will be killed by large scale competition doing storage or hydrogen conversion. IOW: the situation where prices fluctuate a lot won't last forever. 5 to 10 years at most. Also consider net congestion. Last week there was an article in the news saying that grid operators don't like home batteries to charge when prices are low and discharge when prices are high because this results in extra strain on the grid at times where the grid is already under maximum load. So even if you could control charging / discharging home batteries centrally, this likely won't be price driven but used to lower the load on the grid. Maybe this could result in some paypack but likely not enough to make a battery worthwhile. Also keep in mind that a central control system needs to be maintained and operated. Likely the company doing the central control is the only one making money. 'Mine the miners'; the only people getting rich from mining are the ones selling the mining equipment.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: September 20, 2024, 04:19:26 pm
content: Power, that has become a tradable commodity in the streets now , Where i live in Zambia, Lusaka(capitol) we 'might' get 3 hrs pf power per 3 days now, sometimes a afternoon, we charge power banks for each other and hand them around like handshakes almost.Right now de-centralized power systems is keeping this country going in some ways. You see people carrying 'solar generator power packs' to work where they hope they can tap into company power somehow for taking home to try and keep food cold. Peltier fridges and micro fridges(bldc compressor type) have popped all over the place.We recently(the school I own) went fully solar at great cost (small system 5kw/5kva/5kv but central africa is costly shipping) and our excess is dumped into power banks and SG that our staff bring. We had many experimental small system in the past and donated them to the staff as we upgraded, The full solar i mention is going from simple 12v to full victron+victron mppt/freedom won bat/home assistant log+control done by a pro. We use wifi switches to control pumps/sockets/water heaters so the system wont allow run away's like a tap left open or your next door neighbor tapping into your bore hole pump power.In our case we have such a power deficit that companies that invest in solar for own use and excess to the grid only help us, as a country we did not considered growth of finance and how it affected power usage (more tv's, more massive adverts signs 24/7 , more bribed politicians owning large empty houses with full security lights :-P ) , the wise early on adopted solar early and while it's a lot cheaper now many were able to sell/pass on usable equipment when they upgraded.While this wont sort out the bad management of our countries power it will to some value relief to the suffering on the local population,Foot note, i cannot full blame the power managers as we do have a 7 year cycle on our rains and it shift up and down a bit and we are currently in that poor rain period so dams are dry dry dry.darkspr1te

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 04:29:30 pm
content: Quote from: Electrodynamic on September 20, 2024, 03:23:55 pmI mean, a week ago we commanded 100 of our customers to export to grid during high energy price situation and supplied 500kW to the grid. It's alreadysomething. With current sales rates we are having several MW to control within a month or two. This is already something that can be used to enter the grid stabilization market place(s). Or, just enable customers to get money from spot price markets, like we did a week ago. Or, combine both: sometimes the aims are contradictory but often synergetic. It's just an optimization problem.Quote from: nctnico on September 20, 2024, 03:35:48 pmYou are of course right about being more expensive (per kW and kWh). But remember though that unless we talk about North Korea or something, the world is not a centrally planned engineered-to-be-optimum solution. Nothing is "killed". At the time,bothcost-effective large installations and very cost ineffective distributed batteries are installed. Because people are easy to talk into buying this kind of battery. Many households have loose money at their disposal, orwantto do something. It's not about finding most cost-effective solution, but people buying what they want.Many people buy expensive wrist watches that cost thousands or tens of thousands and offer absolutely no technical benefit over a $100 watch for the purpose of timekeeping. Not to even talk about jewelry. And even poor people buy this kind of crap using loan money.Home batteries are not optimal*, but they are reality. Apparently they are super easy to sell to people. Go figure. A year ago I would have not imagined I would be working in home battery optimization, but here we are.*) especially when underutilized without smart controls

author: Marco
author_rank: Super Contributor
timestamp: September 20, 2024, 04:42:26 pm
content: Quote from: nctnico on September 20, 2024, 03:35:48 pmIf dynamic prices were sufficiently local that would be impossible. If reverse currents on the high voltage grids would cause problems, the dynamic local feed in price could go as close to 0 as needed to reduce the feed in ... in the extreme it could make the load on the high voltage grid zero, how does making it zero add to the load?Even now, what they probably mean is "we want to make all that profit, or at least hand it to friends".

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 04:53:55 pm
content: Quote from: nctnico on September 20, 2024, 03:35:48 pmThis is a ridiculous generalization: obviously it's the polar opposite: prices are highbecause there is lot of use and lack of production. These batteries act as production. When loads and production are distributed and coincide at the same time, itreducesthe peak currents on the grid, on all levels.It seems you don't simply understand how production 180degrees out of phase from consumption cancels out the currents. This is how everything already works in grid.Literally this is what grid operatorswantand theypayto companies like us to do this.As usual, your argument concentrates on some possibly real but pretty specific edge case and generalizes it. Such edge case could be, for example, everyone in one neighborhood, where houses are heated using gas etc. so consumption is low and local distribution network weak, getting into the train of home batteries all at once; basically trying to "manage" the whole grid through that last mile of distribution. Then again, all that happens is local voltage rises and these inverters stop exporting, so it hurts primarily those who jumped into the train.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 05:24:17 pm
content: Quote from: Marco on September 20, 2024, 04:42:26 pmThere is no concept of reverse currents on AC grid. When you add production somewhere, the AC current is just 180 degrees out of phase from consumption, cancelling out and reducing current towards zero. If somewhere production exceeds consumption then the current starts to rise again. You would need to have zero consumption and as much production as worst case consumption ever is, to exceed normal design currents. Current is not a problem.Last mile voltage however might be: because sometimes parts of grid have more than desirable resistance, causing voltages to drop below minimum acceptable during max consumption situation, grid companies compensate by switching to higher transformer taps, so that no-load voltage exceeds nominal voltage. Without production, no-load voltage is maximum too, so as long as it doesn't exceed the maximum it's all fine. But this creates asymmetry between maximum consumption vs. maximum production, which must be managed by either improving the local distribution network, or denying excessively large PV and/or battery installations.

author: nctnico
author_rank: Super Contributor
timestamp: September 20, 2024, 05:34:08 pm
content: Quote from: Siwastaja on September 20, 2024, 04:53:55 pmSorry, but this is what the article says and it comes straight from the horse's mouth (a grid operator) so don't shoot the messenger. What you don't seem to realise well enough is that electricity needs to be transported from point A to point B. If you have production at point A and storage at point B, then there needs to be enough transport capacity between both points in order for storage to be actually usefull. Unfortunately, the transport capacity is lacking in some places. You need to see this as a 3 dimensional problem. Production, consumption / storage AND transport capacity.

author: Marco
author_rank: Super Contributor
timestamp: September 20, 2024, 05:59:48 pm
content: Quote from: Siwastaja on September 20, 2024, 05:24:17 pmOver here the majority of consumption is in a small heavily industrialized western part of the country, the Randstad. This also has most traditional generation and distribution. The population however is much more evenly distributed and with it PV. So now PV power is trying to make its way to the consumption in the Randstad on a grid never really designed for that kind of flow.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 06:15:57 pm
content: Quote from: nctnico on September 20, 2024, 05:34:08 pmI know the drill, it's nctnico nctnicoing again: some yellow mainstream media article about about a technical issue first misinterpreted by the popularizing journalist possibly with political agenda then further misinterpreted by nctnico with more political agenda.You are not a messenger, you are making claims. You might be treated as a messenger if you gave a reference to the article you are talking about so that we professionals working on this field could check what itactuallysays, instead of how you (possibly mis-)interpreted it.QuoteUnless there is a massively serious mismatch between production and consumption, production and consumption cancel each other out, making iteasierfor given transport capacity to handle. But sure, as I said, there are going to be edge cases. Your claims are not valid generalizations. You are not describing a problem, you are describing asolution. Batteries are to grid what medicine is to illness: a cure, a solution; but in some edge cases the cure itself is worse than the illness, and this is perfectly normal. Yet the generalization that medicines are bad or grid companies do not like batteries are definitely incorrect, and I can say it with very good confidence even without reading your mystery source.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 20, 2024, 06:25:56 pm
content: Quote from: Marco on September 20, 2024, 05:59:48 pmYeah, thanks for clearing this up; my point was that the issue is not as much thedirectionof the power flow, but themagnitudeof it. Let me guess that the population outside of the heavily industrialized western part mostly heats their home and hot water (maybe even cook?) using natural gas, and still drive mostly fossil fuel vehicles, and air conditioning still being considered a luxury item of a kind. Therefore, pretty low consumption. If this is the case and the grid is designed for this, it is not a good idea to install overly large PV systems or use batteries to either charge or discharge from/to grid at full power.