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PV and battery


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8 hours ago, ProDave said:

 

What is the typical cost per KWh of storage, for the present commercial packaged offerings?


 

 

Probably somewhere north of £1500/kWh of installed, usable, energy, I suspect, with a life of, at best, maybe 10 to 12 years.  Lithium cells tend to be calendar life limited if only charged and discharged over a modest state-of-charge range, and that's anything between 1% and 3% per year capacity loss from age, so realistically they are probably not that much use after 15 years, and may well only last a year or two longer than the 10 year warranty period some give.  Good quality wet lead acid cells, like Rolls, can last decades, but are cycle life limited, and realistically you would struggle to get more than about 10 to 15 years life from them.

 

So, you need to factor in (on top of all other generation costs and equipment depreciation) a battery replacement cost of probably around 8p to 10p per kWh with most systems that are currently around.  Add in the cost of the generation system, plus the maintenance and equipment replacement cost and you're probably up around 15p/kWh at the very best, and could easily be over 20p/kWh.  Inverters and chargers are going to have, at best, around a 10 year life, maybe less than that, as their internal electrolytic capacitors have a hard life and even long life ones only have a maximum ten year life.  Solar panels will easily last 20 to 25 years, a wind generator may well have a similar life, but will almost certainly be a constant source of maintenance, and that has to be factored in.

 

If you can get batteries with a 30 to 40 year life, for around £1000/kWh of usable capacity, then that brings the cost down a lot.  Assuming 30 years life (which is very pessimistic for NiFe cells) then you're looking at around 3.3p/kWh.  If they were to last 40 years then the unit cost comes down to about 2.5p/kWh.  Bearing in mind that that's the lifetime cost, with no inflationary increase because you've paid for the storage upfront, then that starts to look pretty good, even when all the ancillary costs are added in.

Edited by JSHarris
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9 hours ago, ProDave said:

These are about the only ones I can find for sale. http://www.ebay.co.uk/itm/12V-bank-Nickel-Iron-NiFe-Battery-400ah-10-x-1-2V-cell-/292003393183?var=&hash=item43fcc22e9f:m:m3iaFCECxzgoMsUm4Ksm4bw


 


 

That example is 10 400Ah cells so a total of 4.8KWh of storage. (Not sure what that translates to as actual usable storage) for about £2000  They list several packages of different sizes.  Shame they are the wrong end of the country to me so no easy way to collect and avoid the high transport costs.


 

The rest of the parts to make a DIY system are much cheaper, I would probably make my own charger, buy a couple of cheap Chinese grid tied inverters from ebay and control it all with an arduino.


 

So given you might get say 3KWh of real usable storage, at a total price to build it of no more than £3000, that's £1000 per KWh of storage for a system that should last a lifetime with no battery replacement costs.

 

Is it viable?

 

Well say I could use all 3KWh every day (unlikely but it makes the maths simple) in a year, I would be able to use 1095KWh of otherwise "wasted" solar PV, lets round that down to 1000KWh per year.  Assuming I pay 15p per KWh, that has the potential to save me £150 per year in electricity costs. So that is still going to take 20 years of use, to pay back it's capital costs. So it's marginal to say the least. But at least after it has paid for itself, the batteries would keep on going.


 

What is the typical cost per KWh of storage, for the present commercial packaged offerings?

 

I can't get that link to work. Just me?

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  • 1 month later...
On 19/01/2017 at 20:06, readiescards said:

* Aquion salt water batteries - they told me they expect to release a newer model in next few months. The current one version 2 has a better charge/discharge rate over version 1 (version 1 still for sale in UK though) but still not very good so you need tonnes of them.

 

Aquion gone bust:

http://blog.aquionenergy.com/aquion-energy-inc.-files-voluntary-petition-under-chapter-11-to-target-a-sale-of-assets

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Sad to hear this, but not surprising, given the massive cliff that has to be climbed to get a reliable product like this to market at a reasonable price.  Pretty much all the existing battery core technologies have been around a long time now, yet very few seem to be able to get beyond the engineering prototype stage and into large scale production.  It's taken lithium ion chemistry cells around 26 years to get from initial production to large scale adoption, and even now development is still improving ion exchange cell chemistry and construction, so I think it's probably reasonable to say there's likely to be around a 10 to 20 year period from first commercial production to a large scale reliable battery system being available.

 

The big hurdle for any off-grid storage system is going to be the cost of storing energy.  Current lithium-based ion transfer energy storage solutions seem to all be limited to at most a 15 year service life before cells degrade to the point where they lose too much capacity to be really useful.  So if weight and size isn't an issue (and, unlike vehicles, it probably isn't a concern for domestic off-grid systems) then it probably makes more sense to go with cheaper and well-proven cell chemistries, as they are likely to have a lower whole-life cost.  The really big problem with this is that the big demand for batteries is electric vehicles, so that's where the development funding is going, and electric vehicle batteries have a completely different set of key requirements, with being small and light being close to the top of the list.

 

The only country that seems to be looking at off-grid energy storage pragmatically seems to be China, as far as I can see.  They have a pressing need to generate more electricity and yet reduce pollution levels, so are spending very large sums of money on alternative energy generation and storage.  Interestingly, they seem to have been developing a mix of two battery types, longer life lithium ion cells, plus they're manufacturing ancient NiFe cells again: http://www.changhongbatteries.com/ .

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  • 11 months later...
On 19/01/2017 at 20:06, readiescards said:

 

As @Nickfromwales says yes I'm going off-grid.  I've spent at least 18months investigating this option and asking a zillion questions of many potential suppliers and been to various green energy shows.  In that 18 months things have changed in the battery world. Lots of research money going into batteries so what is best today might be old hat tomorrow, potentially a lot of space and weight. My thoughts on batteries:


* Lithium - the new 2170 Lithium cell from the Tesla gigafactory and Samsung and others I think will reduce Lithium storage costs considerable in the future as they come online.  This is to be in the Tesla Powerwall 2.  Tesla say the Powerwall2 is suitable for off-grid and comes with a 10 year warranty. Only trouble is it needs an extra 'backup' module that they have not yet finished designing (due late Spring 2017).  Lithium has the advantage of a faster rate of charge than lead acid - so when the sun is shinning you get to gather more. Lithium costs more but is supposed to have 3 times the life of lead acid some claim.  Lots of companies entering this market Sonnen from Germany being another.
* Aquion salt water batteries - they told me they expect to release a newer model in next few months. The current one version 2 has a better charge/discharge rate over version 1 (version 1 still for sale in UK though) but still not very good so you need tonnes of them.
* Redflow ZBM - interesting option but not in common use in UK so decided to keep away from 
* NiFe batteries - much longer life than Lead Acid
* Gel sealed for life lead acid - supposedly less life than non-sealed 
* lead acid - Rolls seem the most recommended - might need water monitoring, has a scrap value too

 

I'm ether going for bleeding edge Tesla Powerwall2 or tried and tested lead acid Rolls with a Victron Quattro or Multiplus invertor/charge controller - got to make that decision in next couple of months! I'll have 8.8kWpe and of course a shitty old dirty (to quote @Nickfromwales ) diesel generator, LPG gas cooker & oven and an electric kettle for sunny days only.

 

I am between houses after looking for a plot for a while and have a Welsh made Celtic Rambler Fifth Wheel trailer made and are currently in Portugal. I have 3 X 335w panels with a Victron 200Ah 12v Lithium battery and a Victron Multiplus 3000 VA inverter charger, Victron CCGX, MPPT etc. Works well and volts drop on 180A loads are not a problem at all. Very clever kit Victron, and often used with LG Chem batteries I think.

Edited by Markblox
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1 hour ago, readiescards said:

I gave up in the end of going off-grid mainly because the Tesla Powerwall2 would have been ideal but failed to hit its delivery deadlines for the UK off-grid certification - £26k spent on a long bit of copper instead :-(

Ouch.!  

 

 

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1 hour ago, readiescards said:

I gave up in the end of going off-grid mainly because the Tesla Powerwall2 would have been ideal but failed to hit its delivery deadlines for the UK off-grid certification - £26k spent on a long bit of copper instead :-(

 

 

Elon Musk's techno folk hero status in the US masks some unsustainable corporate finances. You had a lucky escape.

 

Voluntary off gridding, as opposed to being off grid by necessity, only makes sense if you believe the major Western nations are teetering on the brink of systemic collapse and dystopian social chaos is just around the corner. 

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21 minutes ago, epsilonGreedy said:

Western nations are teetering on the brink of systemic collapse and dystopian social chaos is just around the corner. 

Yes, I was watching a movie made in 1952, said that the world had had it and the future was in space.  Made me chuckle.

All my life I have heard that the world is going to hell in a handcart, or similar.

But all my life the world has got better and better.

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“It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to heaven, we were all going direct the other way - in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only.” 
 Charles Dickens

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4 hours ago, epsilonGreedy said:

 

Elon Musk's techno folk hero status in the US masks some unsustainable corporate finances. You had a lucky escape.

 

Voluntary off gridding, as opposed to being off grid by necessity, only makes sense if you believe the major Western nations are teetering on the brink of systemic collapse and dystopian social chaos is just around the corner. 

Can you PM me first, roughly 5 mins before I need to panic. Just want a head start :D  

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  • 7 months later...

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