Batteries and inverters going off grid with solar.

[TheElectricChicken]

Going off grid in the UK is totally pointless waste of money!  Take the same capital, put it in[.....]

Now that IS insane, you can't taper a ponzi scheme and the UK is almost maxed out on it's bubble economy. Speaking of Maxed out, Max Keiser is a brilliant source of information that anyone can understand about this. The LAST thing any sane person would want to do right now is put money into the market. Solar panels ON your roof can't crash all at once the way the stock market can. Well, perhaps a few extra bolts.... as for the markets, you CANNOT taper a ponzi scheme. Can't be done.

edit: add search www.google.com.au/search?output=search&q=taper+ponzi

[splin]

I'm confused. The listings generally refer to full discharge cycles and that the batteries can take five or 700. Now what you are saying is that these discharge cycles are only to 50%. I thought the whole idea of only discharging to 50% was to never enter that region of discharge that permanently damages the battery and reduces its lifespan. At this point I might as well get car batteries.

If a cycle life is quoted at all for cheap leisure batteries they rarely provide any details, but where they do 50% DOD is typical. Even then they never detail the test conditions - what rate of discharge? How long before the batteries are recharged? How long a rest before the next cycle? Temperatures? You can be certain your operating conditions won't match the ideal conditions used for their quoted cycle life hence you will probably fall well short - especially when recharged by solar PV which is generally a poor match to lead-acid requirements.

Forklift batteries typically quote 1500 cycles @ 80% DOD - because forklifts owners don't want batteries any bigger than they need them to be so they need to be able to use most of the capacity.

Car batteries? Forget them - they are designed for high currents for starting engines but very low DOD. You might only get 50 cycles if you deep discharge them.

You  might find this interesting as it provides a lot of detail as to why paralleling batteries is problematic:

http://physics.ucsd.edu/do-the-math/2012/12/death-of-a-battery/
https://www.google.co.uk/search?q=battery+tall+cells+corrosion+discharging+overcharging&biw=1252&bih=866&ei=6ZjUVevBMsutabbxiNAF&start=20&sa=N

Forklifts batteries are probably a good choice but they do have their own problems apart from their sheer weight. Being tall cells, stratification of the electrolyte is a problem which can lead to plate corrosion. To avoid this you need to charge them with enough gassing to mix the electrolyte - but this itself is damaging the cells through excessive overcharging. Alternatively you could use an air pump to bubble air through the acid.

This provides some useful information:

http://www.battcon.com/PapersFinal2013/11-Larry%20Meisner%20-%20The%20Effects%20of%20Mechanical%20Electrolyte%20Mixing%20VLA%20Cells%20in%20Renewable%20Energy.pdf

You can buy 2V 1000A forklift cells from BimbleSolar for £161 which at £80.5/kWh is the same as a 12V/110Ah £106 leisure battery - except it is rated for 1500 cycles @ 80 DOD. Again, I'm not recommending BimbleSolar, its just that they are about the only website I can find showing a price for a forklift battery.

[Simon]

Sorry to say, but i can think of very many better ways to "stick it to da guverment" than this!!


Going off grid in the UK is totally pointless waste of money!  Take the same capital, put it in a suitable ISA (tax free) your pension (taxfree) or invest abroad( could be tax free if you have a good accountant.....), or best, use it as a deposit on a BTL property!

Then wait 10 years, retire early, and emigrate to a nice hot country with good beaches and a favourable view on rich british ex-pats..........   ;-)


Take THAT you  pesky Parliamentarians!   

I've already done the expat thing the other way around. If I've not bored the pants off you already about how crap italy is I can do next time your in  . Every country has it's problems although most british expats i knew in italy were miserable bastards who lived in isolation thinking highly of themselves and that provided them with enough fun, if all you want to do is eat good food not a problem. I have no idea what the future holds, other than fuel and raw materials becoming more scarce and/or expensive

There are other sources of power like economy 7 charging which I hear has been done and of course maybe a wood fuelled generator. Garden space is abundant if I had to and it became viable I could cover the whole thing in panels  and it's big enough to put another house on thanks to the substation being in the way of allowing some to do that before I got there.

[Simon]

No that I've seen a datasheet yet but I can get 24x 2V 345A batteries for £1920 that's 16.5KW about 11p/W or 44p/W if i take into account only a 25% discharge and use 4KW of that. It does depend on what you buy as 8.4KW of a different not so commonly used cell type would have been £1440

[nowlan]

Am waiting to see if anything comes from Nickel-Iron and graphene.

[Simon]

well if i bought 16.5KW of batteries for £2000 and assume 25% dicharge for 4000 cycles, that is 4KWx4000 = 16'000 KW

£2000 / 16'000 = £0.125 per KW of capacity, oh dear, I'm paying about that for electric,

The panels themselves will pay for themselves in 5 years

So yes very financially unviable  might have to make it a grid tie system after all.

[max_torque]

Can i suggest some research into "units"??  kW and kWHrs are not the same thing at all!   

[Simon]

ok, ok 

[Seekonk]

While not how to calculate it, he came up with the typical life cost for a battery KWH.  With panels being cheap I run real time power and skip the battery bank.  I have only a car battery for motor surge start currents and sequence loads.  I run a fridge, make all my hot water and run the house for fie months of the year totally off grid.  Everything is done by micro control.  I hate batteries. They should be promoting new ideas here not retarded thinking.

[Simon]

Well see I could pay for a grid tie system (£5000 and up) and get what I get or get one of those free installations where the installer gets to sell any I don't use (assuming they have not all gone bust). panels alone pay for themselves in 5 years, obviously I can't sell it back unless i use an official installer who will put them in the wrong place and cost me a fortune so after the 5 years of inefficient operation on my roof the installers time and the inverter and fixtures need paying for.

But then I can't swallow the fact that the government has given preferential treatment to one company over another. essentially all home owners and installers are now gifting energy to the energy companies to sell at a huge markup well beyond accounting for a bit of profit and transmission costs particularly when you consider that all the transmission network I'd be using is what is on my on street!

[splin]

But then I can't swallow the fact that the government has given preferential treatment to one company over another. essentially all home owners and installers are now gifting energy to the energy companies to sell at a huge markup well beyond accounting for a bit of profit and transmission costs particularly when you consider that all the transmission network I'd be using is what is on my on street!

Ermm... what are you on about? I can't parse this statement into anything that makes any sense.

What company has the government given preferential treatment to?

How exactly are *all home owners* now gifting energy to the energy companies? Presumably you mean those with solar PV and other renewable generation? Are they not being paid far more for it through the feed in tarrifs (> £0.15/kWh) than the energy companies can buy it from the main generating companies (approx £0.05/kWh)?

How are they supposed to "sell at a huge markup" when they actually have to sell it for around £0.11/kWh retail which is less than they are forced to pay for it?

[Simon]

How exactly are *all home owners* now gifting energy to the energy companies? Presumably you mean those with solar PV and other renewable generation? Are they not being paid far more for it through the feed in tarrifs (> £0.15/kWh) than the energy companies can buy it from the main generating companies (approx £0.05/kWh)?

How are they supposed to "sell at a huge markup" when they actually have to sell it for around £0.11/kWh retail which is less than they are forced to pay for it?

I'm actually struggling to find any data on feed in tarrifs. I may be confused by government subsidy and amount energy companies are offering. It seems so far the government has been giving the money away to people with the money to install a system. I don't think that the government at this stage should be subsidizing the home generation market but then heaven fobid the government don't give money to people with money, today a solar syustem pays for itself in 5-6 years, if people want to invest, they should be investing. The subsidy is now going down to 1.63p/KW if so far most of the money paid for FIT if not all was from the government by the sounds of it so that begs the question, what will the enery companie be paying in 2016 ? of course as we abandoned price controlls on anything a long time ago, I think we all know how this will go.

Mean while the government is fretting about the lack of capacity in the energy generation market due to a lack of investment by power companies who will now just smile, lean back in their comfy chairs and say "so how much money is the government willing to give us so that we can invest what we should have invested instead of taking it in profits" And we will all pay again! As it happens coal powered stations take i beleive 30 years to pay for themselves. I think the last one to be comissioned was on the back of a government loan with little to no interest.

[Simon]

All I can find is here: https://www.gov.uk/feed-in-tariffs/overview

As well as the generation tariff, you can also sell any extra units you don’t use back to your electricity supplier. This is called an ‘export tariff’.

You’ll get 4.77p per unit of electricity.

You can sell back half of the units of electricity you generate. You’ll need an export meter if your installation is above 30kW.

You’ll also save money on your electricity bills for the energy you do use.

Now that makes no sense.

[johansen]

All I can find is here: https://www.gov.uk/feed-in-tariffs/overview

As well as the generation tariff, you can also sell any extra units you don’t use back to your electricity supplier. This is called an ‘export tariff’.

You’ll get 4.77p per unit of electricity.

You can sell back half of the units of electricity you generate. You’ll need an export meter if your installation is above 30kW.

You’ll also save money on your electricity bills for the energy you do use.

Now that makes no sense.

in most of the usa you need a separate export meter to backfeed the grid and you will get paid at most half at most of the residential rate. so its utterly unprofitable.

if you have one of the older meters you can back feed the grid and as long as you don't back feed more than you use in a month, they will never find out.
however, that is against the fine print... (no, its not dangerous, buy a legit back feed generator)

another option some people have is to back feed the grid no more than you draw from it at any given instant.
but i haven't found an off the shelf solution that will do that.

^this solution would be perfectly legal if you run your house from a doubly feed UPS. however it will cost you about 100 watts no load losses for a 10KW inverter.

[Simon]

The problem is that things are volatile, you have 3 main points of interest driving the whole thing.

1) the government who may or may not offer subsidies and may or may not put controls in place
2) the energy companies who may or may not be regulated on how much they have to buy the electrity for
3) the fact that there are rules on how much CO2 we produce and therefor potential incentive to spend the "fine" money in the nations own economy to provide a solution that prevents the fine occuring.

Of course all this will be governed beurocratically and not with an engeneering head. To pay near 50p/KW was ridicolous. I firmly beleive in the industry supporting itself but it also needs not be at the mercy of radiacal changes in law and energy companies with no regulation. As far as i can tell the government has been paying over the odds and energy companies have possibly not been paying for the solar power, and I'm supposed to beleive they are about to.

it looks like this site: https://www.abundancegeneration.com/how-to-invest/ might even be a better idea, after all there is economy in scale and better return.

[Aodhan145]

You have to get your system in before the tories tear everything to shreds.

[Simon]

bit late for that and if the big 6 were regulated on this there would be no problem. Obviously all the rish tory voters now have their systems installed so they can abandon supporting the market and not even bother to make sure that once again a huge company can rip you off if they wish. There is no real published data on what tarriffs actually are that I can find.

[CatalinaWOW]

I have been trying to justify putting in a solar system for 20+ years.  It was just getting attractive financially to install a grid tied system in Arizona (about as good as it gets for solar energy) when I moved to a more northerly, forested and cloudy location.  Pfft.  It makes no sense here, and I suspect I am still both south of and in a less cloudy location than Simon.

Twenty years ago people were acknowledging that the numbers didn't work out at current costs, but were predicting rapid inflation of electricity costs.  It hasn't really happened.  As always past performance is not a prediction of future performance, but my crystal ball isn't absolutely positive that electricity costs will go through the roof.

Even for grid tied systems in favorable locations it is likely to get less attractive.  The utility companies have recognized the threat to their business models and are starting to request tariffs for attachment to the grid.  This is even justifiable in general terms.  They do have costs in maintaining the distribution system, and also in making generation match consumption, which have historically been amortized in the electric bill.  When people cut their grid purchases by 50-90 percent or more the costs of maintaining the grid don't drop by anything like the same percentage.  The tariffs proposed seem out of line high relative to the actual costs, but who knows how that will settle out.  Even a charge that matches actual costs hurts the economic case for solar.

[Simon]

the day electricity goes up panels will too, I'm sure we know the way markets operate fundamentally, its about how much can you get.

As i said before I don't mind not being paid distribution costs but we will now be at the mercy of the companies that can do as they please, they have before and will again. When we had a cold winter and consumption went up they doubled their profits over that year, but because of the racus over prices kept them the same or they may have given a 5% cut because of huge cuts in wholesale price, so despite higher consumption, lower wholesale prices and a doubling in profits what did that do ? they claimed the 5% cut in prices had harmed them and made 2000 people redundant to cut costs. This is why my original plan was to go off grid, I know what they are like, we all do or we choose to ignore it.

One day resources will get scare and they prices will have to go up.

[bills]

I have been trying to justify putting in a solar system for 20+ years.  It was just getting attractive financially to install a grid tied system in Arizona (about as good as it gets for solar energy) when I moved to a more northerly, forested and cloudy location.  Pfft.  It makes no sense here, and I suspect I am still both south of and in a less cloudy location than Simon.

Twenty years ago people were acknowledging that the numbers didn't work out at current costs, but were predicting rapid inflation of electricity costs.  It hasn't really happened.  As always past performance is not a prediction of future performance, but my crystal ball isn't absolutely positive that electricity costs will go through the roof.

Even for grid tied systems in favorable locations it is likely to get less attractive.  The utility companies have recognized the threat to their business models and are starting to request tariffs for attachment to the grid.  This is even justifiable in general terms.  They do have costs in maintaining the distribution system, and also in making generation match consumption, which have historically been amortized in the electric bill.  When people cut their grid purchases by 50-90 percent or more the costs of maintaining the grid don't drop by anything like the same percentage.  The tariffs proposed seem out of line high relative to the actual costs, but who knows how that will settle out.  Even a charge that matches actual costs hurts the economic case for solar.

Ten years ago the numbers did not match for me but I went ahead anyway total cost was 18k after rebates and tax credits.
The system paid for its self in 8 years, my total cost for power is about $250.00 per year.
Was 200-350 per mo.

[mtdoc]

10 yrs ago, PV panels cost $ 5-10 per watt here. Now they cost $0.50 - 1.00 per watt, a 10 fold decrease.

So today you can get more PV electricity production per $ in a relatively cloudy region (say NW Washington State where I live) than you could in a sunny area ( like Arizona) 10 years ago.

[bills]

I plan on adding 2 more 235w panels to max my inverter out and see if I can get to 0 cost per year should be a 2.5 year pay back.

[Simon]

Well somebody beat me to it. I was wondering if I would upset people if I replied to such an old topic. But today I should be getting six 250 W panels and a Sunny boy grid tie inverter for just under £1000. Not sure they are new but as long as they work I'm not too bothered.

I abandoned the idea of batteries as obviously that technology is yet to mature. I think as electric cars develop the battery technology will come down as a side effect for other things. The grid tie inverter is anyway only meant for solar panels or at least so they say. I know I won't get paid for any of my energy which I estimate to peak at about 5 to 600 W per hour so if I am at home during the day that or something less will happily run my computer which is usually left on anyway and as others suggested I could time things to happen when the sun is out like my washing machine (that has a broken heating element anyway) and I am also an avid user of a dehumidifier as it means particularly in the winter that I can actually breathe through my nose and of course I have a fridge all things that would benefit regardless of whether I'm there or not. Of course by night meh I will have to pay.

It is a pity that regulations are so tight and inflexible and dreamed up by stupid bureaucrats because at the end of the day the only reason why you need a certified system is so they can make sure they are not paying you to pump diesel generated electric back into the grid and get paid a packet. All they need to do is put the onus on the energy companies to come out and check that you really have the system and of course is going back into the grid and when making it very easy stop people defeating the system. Energy meters could also simply run backwards. If we work on the assumption that the technology should not be subsidised but pay for itself then this is by far the simplest and least bureaucratic method. You use it by night you put it back by day everybody is fair and square. Should you have a surplus which is extremely unlikely in the average home a sensible tariff could be agreed. Obviously this means that the energy you are effectively selling back is being paid at the same rate you buy it and the rate you buy it at also includes transmission costs et cetera. This is simply mitigated by a small increase in the cost of electricity. Yes I hear people crying that everybody would have to pay for that well we are all going to pay dearly somebody does not do something soon. As I mentioned at the beginning of this thread my motivations are more than just economical I just want to do the right thing. if People were incentive to to set up systems like I am the system cost would drop dramatically and it will be obtainable by more people.

The reason why not going for one of those free systems is that I am sure they are already chock-a-block with requests and also my roof faces east and west exactly and is extremely unsuitable as it is also at a steep angle. Had I been in the house next door turned by 90° it would have been perfect. I doubt any of these freebie installers is going to want to put up a frame in my garden in just the right place to face the panels the right way. That is something I will do in my own time I have pretty much all winter now and the ground they would stand on is full of wood waiting to be given to a friend for his wood burner. Buying an official system is beyond a joke considering what I would actually get paid it's pointless trying to pursue the guaranteed payout I will have to lay more money down and probably be worse off financially.

[CatalinaWOW]

10 yrs ago, PV panels cost $ 5-10 per watt here. Now they cost $0.50 - 1.00 per watt, a 10 fold decrease.

So today you can get more PV electricity production per $ in a relatively cloudy region (say NW Washington State where I live) than you could in a sunny area ( like Arizona) 10 years ago.

Agree costs are coming down, but still doesn't work for me.  When I was in Arizona my electrical usage peaked in the summer months (surprise, you need AC in AZ in the summer.)  That was a good match to the solar availability.  I could size a system to provide a relative fixed proportion of usage year round.  Didn't have to worry about how much the utility would pay for excess electricity I produced.  My particular site didn't have any roofs oriented in a southerly direction so I either had to build structure or seriously oversize to the system to work out.  Costs had dropped so much that even with these penalties it made sense.

Now I live in SW Oregon.  Electricity consumption peaks in mid-winter when geometry and clouds seriously limit solar production.  In addition my site offers limited areas where trees don't provide significant shading.  These restrictions make a system that provides enough power to put a dent in winter consumption very large and costly.  Rates that utilities will pay for the excess power in summer don't help.  Not surprisingly they don't need extra power in the summer either, since they have sized their systems for the high demand winter months.

By the way, panel costs have dropped to the point where they are not the dominant cost in the system. Further drops in panel prices will not make dramatic changes in solar costs.  The other costs in solar systems are in much more mature technologies which can't be expected to drop rapidly.  Things like structures, brackets and wiring.

[Simon]

Yes my (new) inverter that I only paid £245 for actualy costs around the £1000 mark, this starts to dwarf the panel cost as the cost of panels to run it is little more than that. I'm at about halve capacity with so called 1.5KW of panel (which are new) that of course "up here" will only make 750W i estimate so i need another  6 250W panels to get to the 1.55KW the inverter can do.

But even in autum as we are with the panels left flat on their back I'm getting 500W, it's a pity I have a large tree in my garden as it means i need to spent money to put the panels on a frame to increase their height. I got 250W at dusk but I think that was a specific combination of cloud as well that scattered back the sun rays that were in totally the wrong direction.