Solar PV Hints, Tips & Troubleshooting

garo

unkel wrote: »

That's no problem as long as you install at least 40kWh of it :pac:

Pm me if you see a good UPS system going for cheap or free. :pac:

daughy

Just wondering has anyone had any input from companies in Ireland regarding vehicle to grid charging.
Potentially 30 to 60 kwh of battery sitting in your front garden if you have an electric vehicle.
I would only be interested in this if I can just power the home, not send back to the grid. Will do some research on it.

The losses would be staggering though, dc solar to ac, then ac to dc car charging, then dc car back to ac home.. My god

unkel

Most western countries have had trials of V2G / V2H at this stage. But not here afaik. It's pretty straight forward, you'd need a smart charge point and a car that can handle bi-directional charging / discharging

Losses and inefficiencies are not important. At times the value of electricity is zero (or negative) because we produce more renewables than we can consume or share with other countries at which point utility companies will pay you to please take the electricity off their hands. This already happens quite often, even in this country

I'm running a soft gridder-esque test at the moment and I'll post the results when they are in. Look folks everyone keeps refuting what I'm saying but nobody offers any data to back it up. There's too many associated losses with running batteries instead of utility to be viable. It's lemming central. As long as we have demand over supply for clean power the battery is a deadweight.

I've heard that one before; this and that are on trial. What are they testing? People arre willing to pay for it. Look the answer is in front of your faces measure the lifetime cost of the system in money and energy and then proclaim it's merits. All I'm hearing for all the evidence i offer is I disagree because someone with an invested interest says otherwise.

Asbestos was a great idea back in the day too.

antoinolachtnai

Sir Liamalot wrote: »

I'm running a soft gridder-esque test at the moment and I'll post the results when they are in. Look folks everyone keeps refuting what I'm saying but nobody offers any data to back it up. There's too many associated losses with running batteries instead of utility to be viable. It's lemming central. As long as we have demand over supply for clean power the battery is a deadweight.

I've heard that one before; this and that are on trial. What are they testing? People arre willing to pay for it. Look the answer is in front of your faces measure the lifetime cost of the system in money and energy and then proclaim it's merits. All I'm hearing for all the evidence i offer is I disagree because someone with an invested interest says otherwise.

Asbestos was a great idea back in the day too.

As long as demand is greater than supply then the battery is a deadweight, sure

How are you determining whether demand is greater than supply, on the grid as a whole as opposed to what is going on in one household?

How have you modeled for future growth in PV? With 200,000 6 kW sites in place, will demand continue to exceed supply?

Assuming a quarter of that 1.3GW is in a single 50km x 50km region how have you modeled for what happens at the grid level when is cloud bank blows in?

I am looking at the network not a household....because we're still burning coal and gas in the daytime to rotate steam turbines.
Future growth is every household ought to be rockin' solar.

Flow batteries are good more HVDC interconnectors would be promising.



^ Same cost as a battery.

The battery is a utility solution to a utility problem. Giving it to the end user serves the utility more than the user. Which is greener? 6kW PV and a battery or 12kW PV per houshold?

graememk

Sir Liamalot wrote: »

I am looking at the network not a household....because we're still burning coal and gas in the daytime to rotate steam turbines.
Future growth is every household ought to be rockin' solar.

Flow batteries are good more HVDC interconnectors would be promising.



^ Same cost as a battery.

The battery is a utility solution to a utility problem. Giving it to the end user serves the utility more than the user. Which is greener? 6kW PV and a battery or 12kW PV per houshold?

Out of interest.. how much could you oversize an array,

Ie 8.5kwp on a low slope roof with half facing NE (-130)and other half SW( +50), on a 6kw inverter?

It's a product of acceptable Voc and Imp. I put 200% on my last until I got a bigger one...then I got more PV...that's how it goes. I'm running 140% now.

I think a lottov people say 120%. The correct answer is in the manual.

antoinolachtnai

Sir Liamalot wrote: »

I am looking at the network not a household....because we're still burning coal and gas in the daytime to rotate steam turbines.

We are talking about the future network now with Gigawatts of PV.

A big proportion of turbine generation in the mix is required to provide inertia. You can’t reduce the turbine generation beyond a certain point. Household PV will never provide inertia.

Just because gas turbines are running does not in itself mean there is more demand than supply for PV electricity.

PV will never provide cover for intermittency.

Future growth is every household ought to be rockin' solar.

Flow batteries are good more HVDC interconnectors would be promising.



^ Same cost as a battery.

The battery is a utility solution to a utility problem. Giving it to the end user serves the utility more than the user. Which is greener? 6kW PV and a battery or 12kW PV per houshold?

What does it mean to say ‘greener’?

By greener I mean highest offset of hydrocarbon based fuel usage.
First of all there's triple the clean power on the network because double the solar and minus the associated battery losses and second hydrocarbons were not used to fabricate a battery to reduce the solar output in the first place.

What hard evidence has anyone to offer that a domestic battery is beneficial to the network or householder?

daughy

Sir Liamalot wrote: »

What hard evidence has anyone to offer that a domestic battery is beneficial to the network or householder?

Wild fires? Hurricanes? Earthquakes? If the grid is down a domestic battery is beneficial to the people?
Ireland doesn't suffer as much as others it's true.
But if you can offset the charges during the day by using solar and use your battery at night you'll really see a difference in your lecky bill.

daughy

daughy wrote: »

If the grid is down a domestic battery is beneficial to the people?

Two things there.
First due to anti-islanding protocols most on the market battery options will go offline and take the PV with it in the event of a powercut. The second is li-ion is too small and expensive to offer any considerable runtime in the event of a powercut for a gridder house.
I've 15kWh (usable) and it's a stretch to make it through one day

daughy wrote: »

But if you can offset the charges during the day by using solar and use your battery at night you'll really see a difference in your lecky bill.

Have you any hard evidence to support that there's any net gain after the system losses to make this viable?


I'm still running tests. The initial results are pretty damning but I have to change the parameters for a cleaner result. I'll have interesting data in a few days.

daughy

Sir Liamalot wrote: »

Two things there.
First due to anti-islanding protocols most on the market battery options will go offline and take the PV with it in the event of a powercut. The second is li-ion is too small and expensive to offer and considerable runtime in the event of a powercut for a gridder house.
I've 15kWh (usable) and it's a stretch to make it through one day






Have you any hard evidence to support that there's any net gain after the system losses to make this viable?


I'm still running tests. The initial results are pretty damning but I have to change the parameters for a cleaner result. I'll have interesting data in a few days.

For instance, my electricity meter readings since I installed my system are half of what they where last year, I only installed the system in the middle of August and I messed up doing an East array, for 1 string, South on the other, either way I'll change the east to west and add another 5 panels to it. So even though I messed up with my array, the meter readings are hard evidence that something is working?
Now add a battery to the mix and use it at night? And wollah.. We have lift off heuston..
Seriously though.. Its basic physics
Use the grid as a battery for the day and use your own battery at night. If the grid goes down entirely just cut back on your loads.

Basic physics? :rolleyes:
That's an opinion, there's no data to back up your claim.

Where's the quantifiable, measurable difference?
The Viability assessment?
Return of investment?
Cost of system versus cost of import?
Efficiency report.

Did you spend over the odds for a minor saving?
The lifetime cost of the system versus the savings made?

The comparable output to not have a battery in the middle?

daughy

daughy wrote: »

For instance, my electricity meter readings since I installed my system are half of what they where last year, I only installed the system in the middle of August and I messed up doing an East array, for 1 string, South on the other, either way I'll change the east to west and add another 5 panels to it. So even though I messed up with my array, the meter readings are hard evidence that something is working?
Now add a battery to the mix and use it at night? And wollah.. We have lift off heuston..
Seriously though.. Its basic physics
Use the grid as a battery for the day and use your own battery at night. If the grid goes down entirely just cut back on your loads.

You have 15kwh usable? So your using lead acid? You are only able to use 50 to 60% of the 30kwh battery. How much at the time did you spend on 30kwh of batteries? That's an expensive system to only be able to use 40% capacity to keep them batteries safe

It's a mixed LiFePO4 and lead acid on seperate hybrids that are synchronising and have AC coupled chargers. I'm less than €1k into the lead 10kWh (usable) 3.5kVA and about €6k into the LiFePO4 4kVA 3kWh (usable).
Lead I setup in two days, LifePO4 I built over some months.

I am running the test on LiFePO4 because no matter how much evidence I offer I expect that some clever clogs that read something off the internet will not accept that Lead can match Li-Ion in a sprint and outpace it in a marathon on a cost to cost comparison.
The efficiencies and utility are near identical.
The lead battery is almost a decade old and has rated capacity.
The LifePO4 is relatively new and has low hours.

The other 2kWh is compromising of other stand alone systems I can harmonise.

daughy

daughy wrote: »

You have 15kwh usable? So your using lead acid? You are only able to use 50 to 60% of the 30kwh battery. How much at the time did you spend on 30kwh of batteries? That's an expensive system to only be able to use 40% capacity to keep them batteries safe

Apologies my percentages are all over the place, usable to keep the batteries safe is approx 40%

Teaching yer grandma to suck eggs there pilgrim.
50% by the way.

daughy

Sir Liamalot wrote: »

It's a mixed LiFePO4 and lead acid on seperate hybrids that are synchronising and have AC coupled chargers. I'm less than €1k into the lead 10kWh (usable) 3.5kVA and about €6k into the LiFePO4 4kVA 3kWh (usable).
Lead I setup in two days, LifePO4 I built over some months.

I am running the test on LiFePO4 because no matter how much evidence I offer I expect that some clever clogs that read something off the internet will not accept that Lead can outpace Li-Ion in a marathon on a cost to cost comparison.
The efficiencies and utility are near identical.
The lead battery is almost a decade old and has rated capacity.
The LifePO4 is relatively new and has low hours.

The other 2kWh is compromising of other stand alone systems I can harmonise.

If your happy that's the main thing. Nobody wants to be wrong about an investment.
I do hope your lead acid lasts, truly I do as its 100 year old technology, and I do understand lithium is basically in its infancy stages compared to lead, it's just when you look at the first computer compared to ipad or new phone. It's night and day. And unkel mentioned he had no bms on his system, that's a very costly mistake for the sake of the price of a bms.. Not having a dig unkel, just not something I would do as lithium is too expensive to not have a bms on it.. My father has sealed lead acid running his off grid and he has no complaints, I was going to go lead as the cost for lithium is nuts, but knowing I can only discharge safely 40% of its capacity is a deal breaker for me.. Your tests are running for how long now?

antoinolachtnai

Sir Liamalot wrote: »

By greener I mean highest offset of hydrocarbon based fuel usage.
First of all there's triple the clean power on the network because double the solar and minus the associated battery losses and second hydrocarbons were not used to fabricate a battery to reduce the solar output in the first place.

And when the imbalance on the grid is such that there is more energy on the system than is needed?

There is no saving if the householder avoids having to buy a battery but the power companies end up buying a battery somewhere else, and has to build and operate low efficiency OCGT In order to match the PV when the sun is low or occluded.

There are wider public policy objectives related to battery storage. It’s not as simple as making more money in the short term.

daughy

daughy wrote: »

If your happy that's the main thing. Nobody wants to be wrong about an investment.

I'm not trying to make money powering my house with them. That's a side project because I am very tired of the misinfomation in the industry.

daughy wrote: »

I do hope your lead acid lasts, truly I do as its 100 year old technology,

Closer 150. I think that makes it a proven tech.

daughy wrote: »

it's just when you look at the first computer compared to ipad or new phone.

Sure that Ferrari is fast, but it's not €250 000 fast.

daughy wrote: »

unkel mentioned he had no bms on his system,

Penny to a pound Unkel is the BMS.

daughy wrote: »

knowing I can only discharge safely to 40% of its capacity is a deal breaker for me..

50% of 20kWh is a lot more than 70% of 4.3kWh and a fraction of the cost.

daughy wrote: »

Your tests are running for how long now?

I'd say about a decade now.


With regards to hybrid inverters about a fortnight.

daughy

Sir Liamalot wrote: »

Teaching yer grandma to suck eggs there pilgrim.
50% by the way.

Had to laugh at that one. Nice 1 Liam. Can't seem to find emojis on this site. Would be laughing..
Anyway 50%. Might keep the lights on for another hour

antoinolachtnai

antoinolachtnai wrote: »

And when the imbalance on the grid is such that there is more energy on the system than is needed?

HVDC interconnector. Grid batteries are a great idea. Domestic batteries not so much.

antoinolachtnai wrote: »

There is no saving if the householder avoids having to buy a battery but the power companies end up buying a battery somewhere else, and has to build and operate low efficiency OCGT In order to match the PV when the sun is low or occluded.

Grid operators are a lot smarter/well-informed than you and I.

antoinolachtnai wrote: »

There are wider public policy objectives related to battery storage. It’s not as simple as making more money in the short term.

It's not about money, that's just an appraisal device. It's about lowering carbon dioxide production.

antoinolachtnai

You haven’t really presented your reasoning.

You are very concerned about round-trip efficiency when it comes to household batteries but you don’t seem to have accounted for the much larger losses for grid batteries.

Given that, and given that we want to maximize the CO2 saving per euro spent would it not make more sense to put the money being spent by householders on domestic PV into buying a share of a grid scale PV farm? You could get maybe double the kW for the same money that way.

It is heartening that you accept the wisdom of the system operators without qualification.

You haven’t answered my questions from the outset. As a result I just can’t understand your certainty that domestic batteries don’t and will never make sense.

I can’t see much point in discussing it further until you explain your grid level modeling.

antoinolachtnai

antoinolachtnai wrote: »

You haven’t really presented your reasoning.

I'm currently waiting on data that nobody else wants to confront or offer. Everyone just seems to think x+y=z without any validation.

antoinolachtnai wrote: »

You are very concerned about round-trip efficiency when it comes to household batteries but you don’t seem to have accounted for the much larger losses for grid batteries.

Flow batteries, mechanical batteries and pumped hydro are dominating li-ion and none of them fit in a house.
The grid is a battery, unify and increase distribution internationally. How are the losses greater when there's a much vaster power on demand load profile? Any data on that?

antoinolachtnai wrote: »

Given that, and given that we want to maximize the CO2 saving per euro spent would it not make more sense to put the money being spent by householders on domestic PV into buying a share of a grid scale PV farm? You could get maybe double the kW for the same money that way.

Exactly, everyone seems concerned about storage when we haven't enough generators. The battery is the last piece of the puzzle.

antoinolachtnai wrote: »

It is heartening that you accept the wisdom of the system operators without qualification.

Clearly not the Irish as they're more concerned about defending their market than progressing the tech, at least they make an informed viability assessment before committing.

antoinolachtnai wrote: »

You haven’t answered my questions from the outset. As a result I just can’t understand your certainty that domestic batteries don’t and will never make sense.

Which question?
And in return why are you so convinced it is practical, have you based it on any evidence?

antoinolachtnai wrote: »

I can’t see much point in discussing it further until you explain your grid level modeling.

I can see a substantial amount of power being generated getting lost in transistor heatsinks when it could be going to our loads instead for a lower upfront cost.



So if we could take all the taxpayers' money SEAI are throwing in a hole and bribe the ESB to get off their holes and offer a fair market price for homegrown power then the battery would be out on it's ear without a second thought. Would you agree?

Or how about cultivating the West coast offshore with that money instead and exporting power instead of crying that our transformers are too old and few?
We've the best wind in Europe outside of Scotland and have you seen where we are on the generation charts? It's an embarrassment.

antoinolachtnai

Sir Liamalot wrote: »

I'm currently waiting on data that nobody else wants to confront or offer. Everyone just seems to think x+y=z without any validation.

The same is going on everywhere. The idea that just because PV is providing electricity, that it is therefore making a significant contribution to the grid is the same sort of thinking you describe. Not all energy sources are equal in value.

Flow batteries, mechanical batteries and pumped hydro are dominating li-ion and none of them fit in a house.
The grid is a battery, unify and increase distribution internationally. How are the losses greater when there's a much vaster power on demand load profile? Any data on that?

The grid isn't a battery. It's a distribution system. Unlike the food distribution network or the gas grid, it has basically no inherent storage capacity.

Grid connections to abroad are expensive to build. Where are all these grid connections supposed to connect to at either our end or the far end? Running a grid connection to GB won't do you much good if they don't have capacity to match it.

Clearly not the Irish as they're more concerned about defending their market than progressing the tech, at least they make an informed viability assessment before committing.

What grid in the world has more asynchronous renewable at peak than Ireland's?

Which question?

I asked you to provide your model at grid level.

And in return why are you so convinced it is practical, have you based it on any evidence?

I never said that it was practical at all. I just wanted to understand your detailed reasoning taking into account all the factors why you think it's not practical under any circumstances.

There are very compelling things about domestic batteries. They provide capacity, which PV does not. They can help support the distribution network at times of high demand. They can provide benefits at the times of year when electricity is most needed, unlike PV or PV alone.

I can see a substantial amount of power being generated getting lost in transistor heatsinks when it could be going to our loads instead for a lower upfront cost.

The nature of electricity generation, especially from sun and wind collectors is that there is going to be waste. There are going to be times when there is just too much. The whole difficulty with planning generation is that you need a mix of sources. There is no single strategy which will give you everything you need at anything like an optimal price.

So if we could take all the taxpayers' money SEAI are throwing in a hole and bribe the ESB to get off their holes and offer a fair market price for homegrown power then the battery would be out on it's ear without a second thought. Would you agree?

The SEAI has not really spent that much money. The amount is tiny in the context of the overall cost of electricity and the size of the PSO fund (hundreds of millions per year. Maybe you can tell us how much, but I think it is in the order of 5 to 10 million euros. This is a very small program in the overall scale of things. The level of funding required to pay a subsidy for home-PV electricity would be an awful lot more than that.

Sure, the metering is a mess, but that isn't SEAI's fault.

The ESB doesn't set the price for electricity and hasn't for years.

How would you calculate a fair price for homegrown power? How much would it be?

Or how about cultivating the West coast offshore with that money instead and exporting power instead of crying that our transformers are too old and few?
We've the best wind in Europe outside of Scotland and have you seen where we are on the generation charts? It's an embarrassment.

Offshore wind probably makes more sense near the population centres than off the western coast, certainly with the current technology.

It may well end up being a choice between funding offshore wind and funding domestic PV. In the end, all this has to be paid for by the bill payer.

unkel

daughy wrote: »

unkel mentioned he had no bms on his system, that's a very costly mistake for the sake of the price of a bms.. Not having a dig unkel, just not something I would do as lithium is too expensive to not have a bms on it.

It's all relative. You will learn once you start playing with this stuff. A good BMS that will protect my battery costs more than my battery cost. So investing in one would be a terrible waste of money. A half decent BMS doesn't cost much and will protect the battery from overvolt, undervolt, etc. and it will cut off the battery when the cell imbalance becomes too big. It will do a very poor job at balancing the cells though. And my inverter already has the job of overvolt, undervolt, etc. protection and my battery is fused for short circuits / over current, etc. I had a half decent BMS but I decided I would personally take over its function. Liam got it in one

antoinolachtnai

antoinolachtnai wrote: »

The grid isn't a battery. It's a distribution system. Unlike the food distribution network or the gas grid, it has basically no inherent storage capacity.

For intents and purposes is can be. We could send wind to France and get sunlight in return later that day.

antoinolachtnai wrote: »

Grid connections to abroad are expensive to build. Where are all these grid connections supposed to connect to at either our end or the far end? Running a grid connection to GB won't do you much good if they don't have capacity to match it.

Think bigger send it to France cut out the middle man. We have to get over this islander mentality. Once it's on the mainland it can go to China on HVDC. Then it's way more interesting with differential daylight hours.

antoinolachtnai wrote: »

What grid in the world has more asynchronous renewable at peak than Ireland's?

Most of them.

antoinolachtnai wrote: »

I asked you to provide your model at grid level.

Haven't got one, the losses are lower sending power to the grid instead of semi-conductors.

antoinolachtnai wrote: »

I never said that it was practical at all. I just wanted to understand your detailed reasoning taking into account all the factors why you think it's not practical under any circumstances.

I can't beat pure solar on bang for buck with any alternative.
We do not build off-grid around a battery we build it around the generators with a battery. You are doing it right when you are not using the battery. This significance of the battery is misunderstood. What good is a cup without a water source?

antoinolachtnai wrote: »

There are very compelling things about domestic batteries.

Seems to be the cost outweighs them.

antoinolachtnai wrote: »

They provide capacity, which PV does not.

So does the grid but cheaper

antoinolachtnai wrote: »

They can help support the distribution network at times of high demand.

Why would I support the grid when they're short-changing me, increasing the wear and tear and have they not got their own storage?

antoinolachtnai wrote: »

They can provide benefits at the times of year when electricity is most needed, unlike PV or PV alone.

This does not fit an economic or ecological debate. As needs must when the Devil drives.

antoinolachtnai wrote: »

The nature of electricity generation, especially from sun and wind collectors is that there is going to be waste. There are going to be times when there is just too much. The whole difficulty with planning generation is that you need a mix of sources. There is no single strategy which will give you everything you need at anything like an optimal price.

Agreed but this is not a concern of the micro-generator and there is such a low uptake of renewables in this country, we have an awful lot of hydrocarbons to reduce use of before that's ever an issue.

I fit diesels then I reduce their runtime. Reliablity comes before hippy.

antoinolachtnai wrote: »

The SEAI has not really spent that much money. The amount is tiny in the context of the overall cost of electricity and the size of the PSO fund (hundreds of millions per year. Maybe you can tell us how much, but I think it is in the order of 5 to 10 million euros. This is a very small program in the overall scale of things.

Pardon me but there's an awful lot better ways to spend it, before we even get started with all the chancers hiking the install prices way above their value.

antoinolachtnai wrote: »

The level of funding required to pay a subsidy for home-PV electricity would be an awful lot more than that.

Power on the network is a sellable and more valuable commodity than what we're doing with it.

antoinolachtnai wrote: »

How would you calculate a fair price for homegrown power? How much would it be?

ESB import open market value.

antoinolachtnai wrote: »

Offshore wind probably makes more sense near the population centres than off the western coast, certainly with the current technology.

It may well end up being a choice between funding offshore wind and funding domestic PV. In the end, all this has to be paid for by the bill payer.

I don't mind paying for less coal burning. I mind paying for other peoples' green credentials that could perform better overall by throwing half of their hardware away.

unkel

unkel wrote: »

A good BMS that will protect my battery costs more than my battery cost.

Yurp. I've learned that one. The battery has to be really expensive to justify it.


I bought a loada posh balancers, never use them. The cells don't go outtov balance once they are balanced. I can't stand the noise of them. High frequency singing...nauseating!

antoinolachtnai

Sir Liamalot wrote: »

For intents and purposes is can be. We could send wind to France and get sunlight in return later that day.

Think bigger send it to France cut out the middle man. We have to get over this islander mentality. Once it's on the mainland it can go to China on HVDC. Then it's way more interesting with differential daylight hours.

The cost of building transmission is immense.

An interconnector will be built to France because that is the cost of keeping the European project going. There'll only be .7 GW there. If we built a bigger interconnector where would it connect into? We don't have that much transmission in place to connect it to, even within Ireland.

There is great resistance (not the electrical type) to building transmission even here, a politically stable and prosperous place where everybody knows one another. We haven't built any significant transmission in years, even though we are crying out.

There are many other practical problems with building the pan-eurasian transmission system you envisage.

Most of them.


-- graph of renewable proportions in year--

That is a very different statistic. Those aren't grids. Those are countries. A great deal of that renewable electricity is synchronous (nuclear and hydro). Those countries are parts of vast AC connected grids.

You seem to have decided what the model for the whole grid should be without doing any analysis that can be scrutinised. You dismiss other people's analysis even though you apparently don't know the significance of the difference between synchronous and asynchronous power.

I can't beat pure solar on bang for buck with any alternative.
We do not build off-grid around a battery we build it around the generators with a battery. You are doing it right when you are not using the battery. This significance of the battery is misunderstood. What good is a cup without a water source?

Exactly! Both an off-grid setup and the Irish grid is based on stored energy which can be drawn upon as needed. The energy is stored in chemical form as oil or gas, stored either in a tank or in the ground.

This is exactly what we are trying to get away from. We are trying to find an alternative way to have energy available when we need it.

So does the grid but cheaper

It might appear that way, but the grid only has capacity because the dispatchable generators of various sorts provide capacity to the grid.

Why would I support the grid when they're short-changing me, increasing the wear and tear and have they not got their own storage?

The grid isn't a privately owned thing. It is a commons. If everybody takes from it, then it just won't work. The fact that you don't agree with the way the grid is run or allocates resources today doesn't change that.

This does not fit an economic or ecological debate. As needs must when the Devil drives.

I don't know what to say about that.

Agreed but this is not a concern of the micro-generator and there is such a low uptake of renewables in this country, we have an awful lot of hydrocarbons to reduce use of before that's ever an issue.

As things stand, wind sometimes has to be curtailed or constrained. It happens frequently enough. So it is not true to say this is not an issue. It is definitely an issue.

Pardon me but there's an awful lot better ways to spend it, before we even get started with all the chancers hiking the install prices way above their value.

Well, prices are going to be higher than the straightforward cost of the install, for the simple reason that there is going to be a marketing and sales cost to be recovered. That's the nature of rolling out a mass consumer product. It's a fair comment that it might be a waste of money.

Power on the network is a sellable and more valuable commodity than what we're doing with it.

It's worth 4c a kWh maybe. Once there's a load of it on the grid, say 1.5 GW, it'll probably be worth less.

ESB import open market value.

The ESB (electric ireland) price isn't an open market value necessarily. They sell electricity at all different prices.

You mean the wholesale price that electric ireland pays for electricity and that ESB powergen gents paid for selling electricity? Day-ahead price, which is a 'true' market price in the sense that there is open bidding and offering)? Imbalance price? Would you be happy enough to be paid (really pay) a negative price?

I don't mind paying for less coal burning. I mind paying for other peoples' green credentials that could perform better overall by throwing half of their hardware away.

For domestic retrofit PV, a lot of this money won't go on gear at all. It will go on four things, heights insurance, scaffolding, sales/service and marketing. I don't see how you can do the projects at any scale without these costs.

That's all very well if it makes people engaged in the whole process.

unkel

Sir Liamalot wrote: »

For intents and purposes is can be. We could send wind to France and get sunlight in return later that day.

This.

Europe is a great example of how we can maximise interconnecting. In a decade or so Spain needs to have the PV capacity of many times their own needs. Ireland needs to have the wind capacity of many times our own needs. Norway hydro, France nuclear. You get the picture.

Interconnectors are the "batteries" we need most and are most economical. Hydro storage is next. And somewhere after that is using batteries that we already have (EVs). Dedicated grid attached battery storage for our over production is far down the line. Somewhere slightly ahead of producing hydrogen with that same excess

antoinolachtnai

antoinolachtnai wrote: »

The cost of building transmission is immense.

An interconnector will be built to France because that is the cost of keeping the European project going. There'll only be 1 GW there. If we built a bigger interconnector where would it connect into? We don't have that much transmission in place to connect it to, even within Ireland.

Can we not get a loan as you say yourself we've paltry wind and nowhere to put it? We've a massive resource and we're not developing it.

antoinolachtnai wrote: »

There is great resistance (not the electrical type) to building transmission even here, a politically stable and prosperous place where everybody knows one another. We haven't built any significant transmission in years, even though we are crying out.

Too much NIMBY. Yet people are happy with CO2 pumping into the atmosphere alternatives. I can't understand it myself. If people have a problem with turbines then take the main fuse outtov the consumer unit is my stance.

antoinolachtnai wrote: »

There are many other practical problems with building the pan-eurasian transmission system you envisage.

I thought it was underway. Seems that there's a wee gap between Russia and India

antoinolachtnai wrote: »

That is a very different statistic. Those aren't grids. Those are countries. A great deal of that renewable electricity is synchronous (nuclear and hydro). Those countries are parts of vast AC connected grids.

You seem to have decided what the model for the whole grid should be without doing any analysis that can be scrutinised. You dismiss other people's analysis even though you apparently don't know the significance of the difference between synchronous and asynchronous power.

Nope just oversimplifying it. HVDC will dominate transmission. I hear ya knockin'. Grand so 50hz HVAC. The point was more use the international grid not a battery is all. It certainly wasn't me claiming to have a better take on the how.


The boundary is getting muddy on are we talking domestic, national or international.

What I am pointing out or trying to is that putting a battery in every house is lossy and expensive. There'd be more clean power for better value for everyone if we generate and utility store. As regards the transmission losses the storage can be local to point of use rather than big remote plants, utility is in a much stronger position to maximise viability.

antoinolachtnai wrote: »

Exactly! Both an off-grid setup and the Irish grid is based on stored energy which can be drawn upon as needed. The energy is stored in chemical form as oil or gas, stored either in a tank or in the ground.

This is exactly what we are trying to get away from. We are trying to find an alternative way to have energy available when we need it.

Agreed. I don't think we are going about it very well by these tiny tribute batteries in people's closets. (Oh how we will laugh in a coupla days when my numbers are in and I'm eating humble pie..:pac: )


I've 20% losses outtov the gates atm and that's very favourable because the results are contaminated with power on demand. The unit I'm using is 95% claimed efficiency by the way. I've tested it at 79% round trip at C1.5 with unity power factor.

antoinolachtnai wrote: »

It might appear that way, but the grid only has capacity because the dispatchable generators of various sorts provide capacity to the grid.

I understand. We'd be dispatching less of them with more solar and less closet batteries.

antoinolachtnai wrote: »

The grid isn't a privately owned thing. It is a commons. If everybody takes from it, then it just won't work. The fact that you don't agree with the way the grid is run or allocates resources today doesn't change that.

er..no I'm saying that without the closet batteries we'd have more power on the network hence less burning coal. This is all. I did get sidetracked with the whole why are we so inept at RE generation though.

antoinolachtnai wrote: »

I don't know what to say about that.

It means that our standards change in times of need. If the grid is down then the >€7k of hardware sitting in my workshop is priceless.

antoinolachtnai wrote: »

As things stand, wind sometimes has to be curtailed or constrained. It happens frequently enough. So it is not true to say this is not an issue. It is definitely an issue.

Oh dear, oh dear...new can of worms. Why are we braking turbines? Can we not have a dump load like a [dare I say it] hydrogen electrolysing plant [gets ready for a flaming].
Sure terrible idea but is there not a profitable way to dump the power instead of helicoptering engineers to nacelles to apply brakes?

antoinolachtnai wrote: »

Well, prices are going to be higher than the straightforward cost of the install, for the simple reason that there is going to be a marketing and sales cost to be recovered.

You know I've noticed all my prefered brands don't advertise?
It's just the mediocre ones feel they have to.

antoinolachtnai wrote: »

That's the nature of rolling out a mass consumer product. It's a fair comment that it might be a waste of money.

Indeed. My stance remains unchanged. Grid tied solar is a far better deal than grid tied batteries with solar. I will eat my words publicly and with pride if the numbers I have after the weekend show me I'm incorrect to believe so.
It's better for the network, it's better for the planet, it's a better deal all round. If it's marginal and has applicational merits i will broadcast that too.

antoinolachtnai wrote: »

It's worth 4c a kWh maybe. Once there's a load of it on the grid, say 1.5 GW, it'll probably be worth less.

4c a kWh more in the right direction than a battery cost.

Do you not find it odd that nobody has any comprehensive data on their system performance. Sure people have apps to show them what the power is doing but not the whole picture of what went into the device compared to what came out?
Not even the sellers and distributors.
Why am I the only one asking?
Is that not an important detail?

antoinolachtnai wrote: »

Would you be happy enough to be paid (really pay) a negative price?

Are you mad? I've plentya better things to do with it that sell it for negative equity.

antoinolachtnai wrote: »

For domestic retrofit PV, a lot of this money won't go on gear at all. It will go on four things, heights insurance, scaffolding, sales/service and marketing. I don't see how you can do the projects at any scale without these costs.

If PV only has to pay for PV. Not PV + battery doesn't that half the expense if the system is designed to suit the load profile?
Spare me the marketing. I can tell more from a datasheet and a meter.
In fact needing to prop a product up with marketing is very telling indeed.
Also I'm not interested in the warranty, I don't buy junk. So can I have that 10% back too?

antoinolachtnai wrote: »

That's all very well if it makes people engaged in the whole process.

Provided they're not being taken for a ride.

daughy

unkel wrote: »

It's all relative. You will learn once you start playing with this stuff. A good BMS that will protect my battery costs more than my battery cost. So investing in one would be a terrible waste of money. A half decent BMS doesn't cost much and will protect the battery from overvolt, undervolt, etc. and it will cut off the battery when the cell imbalance becomes too big. It will do a very poor job at balancing the cells though. And my inverter already has the job of overvolt, undervolt, etc. protection and my battery is fused for short circuits / over current, etc. I had a half decent BMS but I decided I would personally take over its function. Liam got it in one

I haven't got around to installing a lithium system on my setup, or even a lead acid at this stage, I have installed lead acid in the past on a different system and that was 5 years ago, only a small system, 24 volt 220 amp hours, just a charge controller and a 2kw inverter, but it's just for running a fridge. Liam are you testing the efficiency of the hybrid inverter or the lithium cells themselves?
I'm still learning about lithium and its characteristics and if its actually worth spending the large upfront costs, plus alot of people that have these closet batteries are in a residential environment, not all people live on farms with acres and acres of land and fields beyond the eye can see to have as many panels as one would desire. I didn't choose a rail mounted system on my roof as my roof is what keeps the rain from falling on my head, I just don't trust drilling into my roof, and the uplift over time from wind, I'm not telling anyone else what to do, just my opinion. Plus you can clean the panels easier on the ground.. And if one goes bad you can just add easily swap it out without getting a roofer. Anyway, just my opinion.
Has anyone here except for Liam run an off grid setup as even a test for a couple of days with lithium? Would be nice to hear your thoughts on the charge and discharge rates and are you happy with your results. If you had lead acid in the past can you see different results?
More capacity, longer run time, less maintenance, anything else one can think of you can post it here. Don't be afraid of the big bad wolf, his bark is worse than his bite ha

daughy

I'm searching for a simple battery operated WiFi hot water thermostat to connect the probe to my hot water tank to keep an eye on the temperature when away from home, I'm not interested in getting a hive or nest as that's too expensive, just something I can check on phone for the temp of the tank, has anyone got any recommendations. Something cheap I hope.

daughy

Well I found something cheap if anyone else where looking for something like this.

its on amazon with the probe,
https://www.amazon.co.uk/dp/B0813CN56X/ref=cm_sw_r_em_apa_fab_1ESGFb4ZG7N5J

daughy

daughy wrote: »

Liam are you testing the efficiency of the hybrid inverter or the lithium cells themselves?

System viability and applications. Testing with an end goal of competing with diesel.


I actually mostly got into Li-ion to prove that the masses were drinking too much kool aid.
Lead and Li-Ion have the same efficiency and practical applications as eachother. Li-ion has about a 2% efficiency lead.

My next test to to dedunk MPPT being significantly better than PWM if you match the solar array to the battery voltage correctly.

daughy wrote: »

plus alot of people that have these closet batteries are in a residential environment,

My 20kWh fit on a rack less than 1m³

daughy wrote: »

Has anyone here except for Liam run an off grid setup as even a test for a couple of days with lithium?

I'd say that's highly unlikely given the cost and the tiny size.


Anyone can buy 60kWh of lead traction for the same price as 5kWh of li-ion. Anything less won't cut it for an off-grid house.

daughy wrote: »

Would be nice to hear your thoughts on the charge and discharge rates and are you happy with your results.

I can charge lead at C3 and discharge at C1. Given the size of a lead battery for the cost it performs every bit as well as a closet battery.

daughy

Sir Liamalot wrote: »

My next test to to dedunk MPPT being significantly better than PWM if you match the solar array to the battery voltage correctly.



My 20kWh fit on a rack less than 1m³

I remember using a PWM controller for my first setup and it was when I was starting out, small 12 volt battery, testing purposes only, the 100 watt panel 12 volt, at the time was getting around 20-30 watts from the PWM.
So I stepped out up to an mppt and the results where significant. 60 to 70 watts at least..
What would be the purpose Liam of doing such a test?
If PWM are aware they can modify the voltage to suit the panels and vice versa wouldn't they have told everyone to do it and not lose money to the competition mppt?
I do like lead acid for price but not for the maintenance that comes with it. The weight, the size, the gasses they release, the constant filling of water, the over charging to keep the plates clean every month or so, cleaning the terminals from corrosion, dangerous acid to name but a few.
But I suppose its a hobby for some.
Will be interesting to hear if your theories are correct. I'm guessing Elon Musk will have to modify the tesla to incorporate all that extra weight

12v panels are a poor choice for 12v applications they're 22Voc.
If the voltage is correct in the first place an MPPT algorithm is redundant.

The purpose of the test is to see if you can get the same results with less expense & to demonstrate that taking what you read on tinternet as fact is quite misleading. At best MPPT is 15% better not 30% unless you go way off the range on panel to battery voltage compatibility.
I reckon I can get it down to <5%

You can automate lead maintenence for far less than li-ion costs. Recombinant watering kits and stirrers are not expensive.
There's a hellova lot going on in a BMS that make li-ion "plug and play", the same can be done with lead yet people like to compare apples and oranges to justify the expense.
Setting fire if you charge them below 0°C is quite a drawback.


The li-ion lightweightness is beneficial for mobile aplications where the motor has to pull the payload. House batteries generally only move on the install day.
Don't get me started on that charcter. Batteries that sit down without the internet and have internal heaters running all Winter long. Spoofer.

daughy

Sir Liamalot wrote: »

12v panels are a poor choice for 12v applications they're 22Voc.
If the voltage is correct in the first place an MPPT algorithm is redundant.



Setting fire if you charge them below 0°C is quite a drawback.

I agree, musk is quite the spoofer, but he's doing quiet well.
I did start out with just a simple 12 volt 100 watt panel, and a 12 volt battery, PWM. I actually still have it charging to monster size batteries, two grown men just to carry 1 of the batteries, 5 years ago I might add.
Then they made panels with 40 volts open circuit so this 6kwp limit from the esb is really limiting people on the amount of panels they can have, I can safely have 15, 350 watt longis on the 5kw hybrid.
Do you mean the lithiums catching fire if charged below 0 degrees? I just thought the bms would disconnect at low voltage?
And have a temperature sensor connected to the battery?

Some do, some don't. Some throttle the charger, some have heaters.
Indoors and operating temperatures help a lot. There's been a few DIY campers & boats burned down alright.
Unattended with solar....boom!

garo

The elephant in the room Liam has completely ignored - when going on his anti-battery rant - is the mismatch in the time of solar production and consumer demand. An HVDC to France will help a lot but not entirely as Irish peak demand will come when the sun has set or is low in the horizon over most of Europe.


BTW, I totally agree that not every PV install in Ireland has to be accompanied with a battery and an HVDC connector to France is likely a better use of our money. But without storage - either a dozen Turlough Hills or a hundred thousand consumer batteries - there is no squaring the circle. Solar and wind are intermittent and peak demand times are not necessarily when you get peak production.

daughy

He posted on the solar quote forum, i think he needs a break from our drama 😂.
Not stalking him ha

garo

garo wrote: »

The elephant in the room Liam has completely ignored - when going on his anti-battery rant - is the mismatch in the time of solar production and consumer demand.

I'm not anti-battery. I am anti-closet battery on a viability basis.
To repeat myself utility batteries are a great idea. Domestic closet batteries are not. Refute all you want but where's your evidence that it is a good idea? It's all anecdotal rebutals.

garo wrote: »

But without storage - either a dozen Turlough Hills or a hundred thousand consumer batteries - there is no squaring the circle. Solar and wind are intermittent and peak demand times are not necessarily when you get peak production.

Think bigger;
Tidal lagoons.
Compressed gas caverns.
Bio-gas production.
Flow Batteries.
Carbon film batteries.
Pumped Storage.


Why are the only people on the uptake of li-ion the ones who don't measure their performance?
Would anyone bother if there wasn't a grant and a sales spin?
What are the rest of the 10 year more progressive world doing?


Here's my data so far. Read from it what you will. Please bare in mind that I'm using Swiss engineered hardware that is the parent of all these new fangled hardware boxes that are trying to copy it built down to a market pricepoint. It's got a nigh unheard of consistent efficiency across the load profile and a big bottomed transformer.
This is the highest efficiency I have seen what's more usual is 40% losses.


This is our test subject;




A 48V Studer XTM 4kVA dialled up to 60V with 3kWh usable LiFePO4 CalB cells.


Claimed 95% efficient.


After a series of days linked to 2.4kW solar and a back-feed set to 2A (including power factor) 24hour and a back-feed bleed of 180W.





88% efficient @ normal operation (power on demand with overnight back-feed)


Followed up with a more constrained test


Solar Gen on Sunday (seasonal shading issues)






Of which 1.7kWh went direct to load






4.24kWh - 1.69kWh = 2.55kWh went to battery charging.


of that 2.22kWh extracted from the battery after losses went to load.




87% efficient.




Well I'm impressed. Your mileage will vary.


Cost of this unit (ex-labour) could have bought me 19kWh more solar.

garo

Thanks for the results. I bet they are better than you were expecting.

I am all for utility scale batteries. And yes it's not just pumped hydro or Li-ion. Lots of other technologies in the mix.

But here's an interesting counter-point to the utility scale batteries good, dometic batteries bad narrative:

https://renew.org.au/renew-magazine/solar-batteries/solar-and-high-grid-voltage/

Ideally we'd have smart appliances that could use power when there is excess in the grid and switch off at peak times or when the wind dies down. But we'll be waiting a while for those and I wouldn't grudge people a few tens of thousands Li-ion batteries while we await the FiT.

The XTM can use frequency shifting to trigger appliances. I'm not begrudging anyone anything. Just make an informed decision. I have several more of these JFM boxes previous to this the efficiency and pricetag was a hellova lot lower.

[Edit] actually I reckon that's in off-grid operation only...I haven't tried it.

garo

garo wrote: »

Ideally we'd have smart appliances that could use power when there is excess

The old ImmerSun units had this feature. 2 x 3kW sequential PWM outputs and a 10A (?) relay.


They're all failing now at the input terminals and the FETs due to under-cooling.
If you find a good one they're going for ~£150


This new Eddi isn't half as good as the ImmerSun was.

daughy

I am just wondering if its possible to overcome this issue, I think it's possible to have panels on the same string but in different orientations, if I add Optimisers to the string is it possible.
My issue is with the shading in my back garden, the 5 panels I have facing east get the morning sun, if I add another 5 panels to that string and move that array west, I know there will be to much shading in winter as the sun is lower, I have a large shed that has a flat roof which can accommodate 6, 350 watt longi, if I add 5 Optimisers to that 5 panel east array should it not in theory bypass the 5 panels facing east when shaded at 2.30pm... Just a thought..

daughy

Or then again it could be cheaper to add Optimisers to the 10 panel west array when installed, whatever is shaded just add Optimisers.
Either way what do you guys think of adding Optimisers to different orientations

championc

You've somewhat lost me @daughy

If you are looking at East and West only, then all you need is a 2 MPPT inverter - each string will connect into the inverter separately. Your losses in winter from a bit of shade late in the day will never pay for the cost of adding optimizers.

But then you mention the shed. So are you planning on installing on it too ? If so, you may well be worth considering a second separate inverter