Off-grid for beginners

[camillitech]

Hey Paul

Aye Billi, that graph was drawn for 1kW PV.......
You are also, once again forgetting where I live,

Me forgetting ?  , not forgetting where you live , just was  wondering  about the graph in relation to the 4.7kW PV in your signature

I really wish I could update that graph Billi but sadly the chap who did it for me died. I would like to produce a new one without the FE turbine and with the Proven 6.

Cheers, Paul

[billi]

"The plummeting price of PV and the acquisition of a 6kW wind turbine for the price of 500w of PV has made me rethink".

Cool , fair play ,  but  we are talking about second hand gear !  
 a new Proven  6 kw including tower and control gear , would be comparable to  a 25kw- 300000 watt PV  , or ?


Billi

OH , edit ,:  Paul  was here ,   i think you are defnitality right to produce electricity   and oversize it  in Scotland  for winter production , instead going the Wood burner route

[stephendv]

The plummeting price of PV and the acquisition of a 6kW wind turbine for the price of 500w of PV has made me rethink.

This is a double edged sword: on the one hand, cheap PV, yay!  On the other hand, now I can't justify buying a turbine and playing around with something that's more entertaining than statically mounted PV that just sits there and stubbornly cranks out the Watts without any maintenance for years on end, booooo 

Seriously though, PV prices are so low that it often beats other construction materials, e.g. on en.secondsol.com they're selling used 55W CIS panels for 12 Euros, they're 1.3mx0.6m = 0.78m2 that's 15 euro/m2 or roughly half the price of the pine cladding I used for our house and shed!  At those sorts of prices instead of seeing "PV", I see "flat piece of opaque, tempered glass that also happens to produce power".

[biff]

Indeed Stephhendv,
                     PV is boringly reliable and just sits there doing its thing. and you are right, they are the best buy going at present however if you live farther north like Paul and I you cannot do without the wind turbine. You just don,t get the supply around December and January , The days are too short. The wind turbine really comes into its own in the winter winds.
                                                              Biff

[stephendv]

The wind turbine really comes into its own in the winter winds.

Aye, it's all about local micro-climates.  My arch enemy is the fog that creeps in in Nov, Dec, no wind and hardly any sun.  Those are the only days I need to run the genny, and given that the PV products maybe 3% of it's rated power during those days, I'd need another 4kW to stay generator free... unfortunately 4kW of PV still buys a LOT of petrol for the occasional generator run.

[billi]

Accidentally , i got rid of my desktop computer (now on a Laptop)  and bought a  LED TV   ,  ....  that does make a significant  difference in our household , and petrol generator  is not running  , max 15 l Petrol used this winter

[mike-b-]

Could the forum not have a "how do i " section ? made by members. Basics would be a start.

mike

[offthegridandy]

Well for my 2 penny worth.  The start of the thread was "for beginners", I  think off grid beginners falls into 2 significant categories.  Those who will get their hands dirty and those who choose to (as my mum would have said) "have a man in.

If you have a firm come in and erect turbine. install PV or what ever I doubt that the customer, at the outset will have a full understanding of the system, or its real practical limitations.

On the other hand a full or partial "self build" system, very likely built up in stages, is going to  be understood (fully?)  by the owner. Although Paul's system may appear complex, it has developed over the years and I suspect the individual items can to a great degree stand alone in the event of some malfunction; so the basics elements  remain simple. Ie the elements are simple even if the delivery appears complex.  But Paul's situation is unusual.  In my case when I'm working away I'm pretty safe in the knowledge that if all else fails Mr Lister can be at the turn of a switch supplying our "grid".  

 I'm not suggesting either approach is right or wrong and it's maybe partly due to budgets. Given unlimited budget and space it would be so easy to design.

The discussion as to which type of batteries, brand off inverter etc can I'm sure appear very complex to (me) and the beginer. But I think that is putting the cart before the proverbial.

I would start from worst case scenario then set out to see how to improve it improve it. Having calculated your daily energy requirements and decided on days of autonomy from any energy input say 3 days, you can decide on a battery size. If you then assume you'll use a lister genny you can calculate the worst case cost of living off grid.Could be say £1500 per annum in red diesel. EG genny runs for 8 hrs every 3rd day genny uses X litres; calculate annual cost

Cost up the possible capital outlay for genny, batteries and inverter charger.  that is your base line.
At this point every case becomes different, dependent on the actual site and space available. But it isn't be hard to calculate the size of array and suitable charger etc

Now consider various appropriate what ifs.

Ie cost for say 6 Kw PV array plus basic charge controller.

Or say 3Kw WT etc, allow for labour if appropriate.

You can calculate the predicted energy production and compare against your needs.

Now DONT look at payback, your off grid, consider instead how much less diesel for the genny you will have used. You can now see how much power you need to generate to bring that to zero £s spend. How much surplus energy you may potentially have to dispose of now gives you some more data to feed back into your capital outlay costs etc.

Ultimately, assuming your planning a system for a private dwelling I think that each system will be different to some degree reflecting both the individuals concerned, the site and the circumstances.

Whether one can afford the system will further infuence design, ie purchase a larger inverter at out set that can have more PV added at a later date or/and put in extra cabling if trench is dug.

Cheers.

Andy

[heatherhopper]

I would start from worst case scenario then set out to see how to improve it improve it. Having calculated your daily energy requirements and decided on days of autonomy from any energy input say 3 days, you can decide on a battery size. If you then assume you'll use a lister genny you can calculate the worst case cost of living off grid.Could be say £1500 per annum in red diesel. EG genny runs for 8 hrs every 3rd day genny uses X litres; calculate annual cost

Cost up the possible capital outlay for genny, batteries and inverter charger.  that is your base line.
At this point every case becomes different, dependent on the actual site and space available.

Andy has neatly described the basic starting point for any potential off-gridder.

I attach real data for two variations of my off-grid set-up. The numbers speak for themselves although I should point out the following location specifics:
There is some pm shading of the PV during these months - numbers are broadly in line with PVGIS the rest of the year.
Being an exposed spine of the country location wind is very variable and prone to natural turbulence - very unlike coasts or plains.
Not too much should be read into battery SOC - depends on read time vs wind and generator operation.

I believe these real numbers demonstrate a significant issue for off-gridders - the day to day variation of generation from renewables (if you have no Hydro). Unless everything is well oversized compared to your consumption estimate the generator will be needed. Planning with PVGIS and NOABL averages, although a good starting point, can be a little bit misleading.

Looking back I can confidently say the following:
If forced to choose I would have installed the larger turbine before PV - delivers more consistently when I most need it (winter) and has a less pronounced low season. I would have funded it new with FITs and realised a tidy return even after allowing for maintenance.
I would have had a larger battery bank - at the very least 1000ah, the money would have had to be found.
I would only install more PV now if I had nothing else pressing to spend the money on - what I have produces more than I can usefully use (even with diversion heating) in the peak months and I would need a field full to make any appreciable difference in the winter (even without shading).

I hope the numbers may give some help to someone considering off-grid although they are of course very specific to my location and circumstances. Apologies to anyone who can't access Open Office sheets.

[camillitech]

Excellent stuff HH,

what happened around Christmas, no wind or sun, or was the data taking a break 

I truly believe that the heart of a good 'off grid' system is a reliable, professionally (or professional standard) diesel/battery/inverter system. For anyone wishing to live a normal life where you can go on holiday and leave the house in charge of A N Other. Or to be able to call tradesmen in and not be afraid their tools are going to flatten your bank. To have the family around for Christmas, have some 'fairy lights' and not be afraid that your dementia suffering father is going to leave the lights on. To be able to have a workshop with all the power tools you need and not to be afraid of using them.

Then when that's fitted just start adding PV initially, more PV, a turbine or whatever. Sure you can manage just fine without a generator, I did for years using Tilley lamps and a gas fridge and it was great fun. You can also get a gazillion watts of PV for the price of a decent generator but thats not going to help you in December when the roofer turns up with his heat gun to repair the flat roof that's just been ripped off in a gale. 

[biff]

I have often wondered how I would have fared,
                                 With our renewable energy efforts, if I had jumped in the deep end first and not started off with our small 450watt turbine + 2 x 165 watt pv panels. It would have been simply impossible for me to understand when I had to stop drawing from the bank or when to load the system to the max to get the best out of it. This guess work would have been costly and reckless. No matter how many times you read it or hear it, you still need to do it yourself, hands on and learn it properly.
 When the time came, I went for a 2kw turbine and as high as voltage as possible that would enable the current to travel the distance to the house better and using cables that did not cost an arm and a leg. The voltage was also the same as the 12 volt system except for the O at the end. So it was instantly recognisable. The high voltage also meant that my early battery bank strings were easy and quickly put together.
 I also believe that the dump load of 138volts is very suitable for dc immersions. It works very well.
  I preach about modular systems that can avoid serious long term down time, (waiting for replacements inverters/ controllers) and installations that can be easily repaired because the owners can replace each item immediately and remember what does what.
  I intend to post some pics of our own system and how it supplies power to 3 places both from the renewable energy and the generator in the simplest way possible. In the most bullet proof non fancy method possible.
  I fully agree with H/H and a big battery bank and decent wind turbine are a must.
                              Biff
                                                                                      

[billi]

Hi  heatherhopper 

That proven turbine performance...  seems   a  "goldmine" in winter ... 104 kWh on Christmas eve .... hot port 

Can you  tell  the  specs of the systems of the  two  spreadsheets  "Bergey days"  and the second " Proven days"  (or did just the turbine change ?)

Still , quite an investment  , to install a Proven(kingspan)  6 kw  turbine ....

[heatherhopper]

what happened around Christmas, no wind or sun, or was the data taking a break  

With impeccable timing that was when the Bergey gave up. I still have a soft spot for that Turbine even if it did not work for me. Our neighbours have one that has not missed a beat (apart from one shed blade) in 7-8 years. Now Bergey are offering it with a decent controller and at 48v it may be worth a look at - provided the PRC involvement has been removed or checked a bit better. Bergey themselves could not have been more helpful (albeit fruitlessly).

That proven turbine performance...  seems   a  "goldmine" in winter ... 104 kWh on Christmas eve .

Yes Billi but look at this last Christmas:
Date          SOC    PV   Turbine    Total   Gen hrs
23/12/14   71   0.60   53.80   54.40      1.5
24/12/14   97   1.10   84.80   85.90      0
25/12/14   98   1.10   28.30   29.40      3.9
26/12/14   91   1.00   1.80      2.80       2.7
27/12/14   88   0.90   1.90      2.80       1.8
28/12/14   73   2.50   4.40      6.90        0
This with a house full of outlaws who think electricity arrives free from nowhere and a Turkey that was too big for the gas oven!
Still does not make much of a dent in our heating though and I could not consider going down the road Paul has.

Can you  tell  the  specs of the systems of the  two  spreadsheets  "Bergey days"  and the second " Proven days"  (or did just the turbine change ?)

Same system with some extra dump capability for the Proven. AC coupled everything (apart from the Bergey) from day one.

Still , quite an investment  , to install a Proven(kingspan)  6 kw  turbine ....

New at the time would have been a few thousand short of 30k including groundworks etc. At a conservative 11000 kWh and allowing for only 15 years life and some maintenance/renewals (springs, blades etc) along the way FIT alone (rate at the time) would have delivered somewhere around 20% return. I do call that quite an investment, not risk free of course but is any investment? Even at todays FIT rates it would still be a runner.
I should add I wasn't, and am not, awash with cash (think minumum wage level these days!) but this was all part of a property move and I regard going off-grid as a long term investment in lifestyle for which I was prepared to find the money.
Current Turbine is set to repay capital by end 2016 after which everything is profit but this was a very fortuitous acquisition.

[camillitech]

I have often wondered how I would have fared,
                                 With our renewable energy efforts, if I had jumped in the deep end first.
                                                                                      

Well we wouldn't have had so much fun listening to your tales for a start Biff.

[biff]

That is absolutely true Paul,
                           And nobody but nobody would want to listen to tales of  Proven sitting there, for over 6 months, doing  nothing for the want of the proper chip or a bigger Proven being lowered because the shaft was brittle or dodgy and liable to snap, meaning that not only would I have had to lower this machine and find another way of obtaining power but I would have lost my FITs and would have had to accept  scrap metal price for my gleaming new Proven turbine with no compensation from Proven who went to the wall.
 I would love to believe that somewhere there are members who in their future spare time, will adapt AG,s pullers, My own simple wooden rails and learn to change bearings and cure overspeed with AG,s tail or my own idea of smaller blades. Not everyone has the ability or the time to build Hugh,s brilliant designed turbines so the idea of a turbine refurbishment is a good one + folks get involved and folks learn.
                                                   Biff