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Author Topic: Want to view an off-grid system  (Read 4819 times)
Theleos
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« on: June 07, 2010, 05:45:26 PM »

Hi, I'm new here but have some experience with off-grid living aboard a boat. using P.V panels on a 12Volt system, inverter and a 60amp charger powered by a genny.

I have a friend who wants to be off grid on a farm in Warwickshire. The farmer has been using a battery bank & inverter to power smaller loads in the evenings & overnight. Using a 6Kva generator for larger loads and daily battery charging. The very hard winter and some unfortunate generator breakdowns have left a feeling of some disillusionment. Although the preferred intention is still to be off-grid with a P.V array & possibly wind power. This won't be possible until some plannning issues have been resolved. Hence the current practice of charging only by generator.

My request is for my friend to be able to view a fully functional off grid system, to show what is possible. We were hoping to be able to visit such a project within a reasonable drive of the Warwick/Leamington areas Any offers would be much appreciated. 

Regards,
            Peter.

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Outtasight
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« Reply #1 on: June 08, 2010, 08:06:29 AM »

Sorry to hear of your friend's woes.  But total independence from the grid does require a herculean effort and lots of money that will probably never be recouped  Undecided.

I've only managed to be partially off-grid (up to 60% in May / June and pretty much zilch in December / January).  I don't have a generator (too noisy and too expensive) and previously to trying for the off-grid FIT payments, I had a grid powered battery charger that was used to keep the batteries topped up to prevent them from rotting in December and January.  This next winter will be interesting as I'll either have to be very very careful with using any battery power or just resign myself to mothballing the system from the end of November to the start of February to avoid any chance of running the batteries down and then having them sit flat for a week and rot because I can't use grid power to top them up.

Unless you live in the middle of nowhere and grid connection is impossible (or extremely expensive) the best use for off-grid power is just as a backup for areas where the grid is a bit flakey with brown-outs or black-outs.  Normal grid tied solar in these places isn't effective as the solar shuts down when the grid does.  But battery backup grid tie is possible and does keep the lights on.

Why am I trying to run off-grid in the city?  Several reasons:

  • I'm Stoopid.
  • It's an experiment to see just how much solar and battery you need to run a typical household.  Answer: Ermm...  Lots more than I currently have. Sad
  • Ever since I was a kid I've had an unhealthy obsession with batteries and solar panels - My dad gave me a Tandy solar experiment kit.

In fact, it's become clear to me that it is nearly impossible to run a house on just solar and battery (unless your house only has one 10W light bulb and a portable radio).  You need wind and probably another "reliable" source. You're looking at either a small diesel generator to run on veg oil or something like a gas powered micro combined heat & power unit (CHP) or a methanol fuel cell.  I did even try an exercise bike with a washing machine motor as a generator but I'm no Olympic cyclist so I can only make about 1 minute of power at a time doing that.

Some here have had lots of experience with slightly unruly diesel generators running on lard Roll Eyes and even more unruly wind turbines wot self-destruct in the storms...  whistlie.

So it does take above all else a lot of determination to be off-grid (and still live a modern lifestyle).  An irrational and deep seated hatred of utility companies helps too when it comes to rationalising the expenditures...
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Mike McMillan
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« Reply #2 on: June 08, 2010, 01:36:43 PM »

Hi Theleos,
I have spent more time off grid than on, running yachts since the 60's. Our house is miles from any pole and we have been living here off grid quite happily for 8 years. The secret is to over spec everything. I have 6 x 30 vacuum tubes that heat 250 litres in a mains (we do have mains water luckily!) pressured HWT. This has 2 coils, one for the solar and one for the wood burner. It means that all of our hot water is provided for 8 months of the year and a good part in the winter as well. On a December sunny day, it will take the tank from 15 degrees to 40, and we only have 5 hours of sun before it dives behind the trees. We have 8 180 watts 24 v pv panels that give us all we need from 1st of March until 1st November. We have second hand 1000 a.h. batteries (given to me actually) and a victron 80 amp charger that runs off the 5 kv lister in the winter. A 2.5kw A.J. inverter has been running (fingers crossed!) faultlessly for 6 years. The secret is to "manage" your power consumption. We are using 3 kw a day, the fridge and freezer are outside (more efficient) and the hoover is only run when the sun is out and the batteries well up. We have a washing machine (with hot water supply), computers and tele. I am planning to put in a microwave oven soon to save on gas, as the morningstar controller is cutting back on charge by 11.00. In the winter, we turn off the fridge and freezer (cold enough without it) and consumption drops to 1.5 kw a day. At this time of year, the H.W. tank is up to 80 by 11.00, at which point the central heating pump swithes on and sends heat (via the wood burner coil) round the rads. It's always damp here, so the heat is welcome, dries the towels etc. I am planning to add 2 more collectors, can't have enough heat!

Mike McMillan

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Theleos
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« Reply #3 on: June 08, 2010, 09:10:03 PM »

Hi, Outasight & Mike Mcmillan,
                                         Thanks for the responses, I have no illusions about how hard it is to be off grid, from my Narrowboat times,  where we lived 6 months out of 12, usually in the cooler times of the year

The main reason for my friend wanting to pursue an offgrid lifestyle as far as possible. Is that Eon want over 21000
to connect to the grid, plus the cost of the trenching which is about 100metres. Although there is a post on the land, the supply which feeds a farm next door ain't big enough, so a new upgraded service would have to be paid for.
Good eh ??
 
Regards,
            Peter
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tony.
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« Reply #4 on: June 08, 2010, 10:40:14 PM »

peter, most companies will happily let you dig the trench for them, reducing your installation costs.

also was the existing transformer too small to suppy a standard 60/80/100 amp supply, what about asking them for a reduced supply, 40amps for example, cheaper than off grid, but still requiring load monitoring.

may be worth asking this

tony
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ecogeorge
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« Reply #5 on: June 08, 2010, 11:07:42 PM »

I'd start by negotiating a dam site bigger wayleave for the pole on your land and use it as a bargining stick!
rgds George.
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billi
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« Reply #6 on: June 09, 2010, 06:14:08 PM »

Hi Peter

Being off grid is more a hobby for me in south west ireland  and the costs for a gridconnection would have been only 1700 Euro , but Ireland didnot and still do not provide a scheme that i like to support with my renewable units  whistlie

We started 4-5 years ago , like most beginners trying to keep costs down (= small but expensive battery , cheap diesel , generator )

Plan was to ad wind ans PV later  whistlie

Lost the smallish battery after 2 years , killed 2-4 cheap generators in these 2 years =  3500 euro lost just because off thinking "Clever and cheap "

Never had a problem with my Inverter charger combis (6 kva) , in the meantime we ordered  two 1.5 kw windturbines and a 1.6 kw PV  ( i paid 3.5 euro per watt summer 2007 )
Windturbine again a cheap one  wackoold failed after 1.5 years (not built for our climate , but the second one still in the shed will be adjusted to survive "better)

So since 3.5 years my 1.6 kw PV is the only reliable source for our setup  that needs about 8 kwh a day  for a small family home of 3 people ( without  missing compfort)
Replaced the smallish expensive  battery  with a good second hand forklift unit (half the price than the one before but 3.5 times the capacity )

My conclusion was to look out for more PV and found a good deal in another 2.4 kwP  for 1 Euro per watt ( quality panels , but left over from a job in Germany )  installed end of 2009

That brought us nearly through the winter without extra diesel generator help

I know it might sound stupid to oversize PV so much to try to achieve a close to 100 % PV production  even in Winter  , cause one doesnot know what to do with the units in summer ....

Anyhow  again i enjoy it and now even more .... and would do it again  and perhaps ad an affordable   windturbine  like the miniwind

All the best Billi

PS:

PV is cheap now  Lips Sealed  a 5 kw PV, 5 kw true sine wave inverter/charger , 5 kw solar MPPT chargecontroller , a  40 kwh second hand forklift battery @48 volt  , cables and mounting frame is  costing in the region of  16000 euro  Tongue  in my opinion
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Outtasight
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« Reply #7 on: June 09, 2010, 06:23:43 PM »

21k to connect you?  So that you can then spend a lifetime giving them hundreds more Pounds a year?

Must be nice to work in an industry where it's always a win:win deal Roll Eyes

21k would buy him a new 1500 rpm silent diesel 10kVA genset (6.5k), a 3kW Sharp PV array with Morningstar TSMPPT-60 controller (9.5k), a set of 16x 180Ah MK 6V gel batts for about 8.6kWh usable storage (3k), a 3kVA Victron inverter (1.3k) and 700 spare change for wire and accessories...

As Billi says, you could get stuff lots cheaper and used forklift batts are a good way to go (if you don't mind the maintenance work).  I've got some of the MK/Deka batts that I got second hand and a bunch of used UPS batts that I'm trying out that were all just 50 a pop.  Haven't got the space for forklift batts behind me sofa whistlie.

I say f#%k 'em!  Go off-grid!  THEN use the wayleave rental on their pole to pay for your veg oil to run the genset  stir
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3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
Kombi
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« Reply #8 on: June 09, 2010, 09:23:33 PM »

If that helps, a energy neutral house has just been erected in Holland (fair to assume similarish weather to the UK). The house has a generating capacity of 4200kwh/year (about a 5kW PV system) and a 300kWh battery bank (6250A/h @48v). This give it power for one month.
Now just try to price such a system:
5kW PV @3.5/W= 17500 installed
batteries: 48x 2v 3000Ah cell= 93120
I won't bother calculating the costs of the inverter/chargers and others ancillaries items required.

Now your friend may not have the same power requirements as this, nor would he be opposed (I assume) to having a generator assisting with the load. But it just shows the potential cost of going completely off grid.
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stephendv
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« Reply #9 on: June 10, 2010, 08:48:14 AM »

Now just try to price such a system:
5kW PV @3.5/W= 17500 installed
batteries: 48x 2v 3000Ah cell= 93120

But it just shows the potential cost of going completely off grid.

Bargain!  I would have charged much more to use diamand encrusted PV panels and unreasonably sized gel batts.  Getting the inverters to be autographed by Leonardo de Caprio wouldn't be cheap either.

Billi's price estimate is much closer to reality for normal people.
  
« Last Edit: June 10, 2010, 08:50:57 AM by stephendv » Logged

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Kombi
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« Reply #10 on: June 10, 2010, 10:11:19 PM »

I was giving an example based on the system set up for the dutch house and quoting prices for new items only. I agree that the system is complete overkill, but the point was just to show how it can quickly get very expensive. As always it is the battery which is the most expensive item. You can't compare a brand new 3000kWh battery bank and a ex-fork lift 40kwh one.
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billi
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« Reply #11 on: June 11, 2010, 07:57:30 AM »

Hi Kombi

The question is in the described set-up  with a 48x 2v 3000Ah cell battery : Why  spent that amount of money  on a battery ?  And not on more PV ?

Perhaps they have no space for more PV , but 93120  invested into PV instead of the battery will pay for ca a 30 KW PV ( at their expensive prices)  and will generate more than double of their needs  on an average January day ! So heating would than be free  whistlie

Billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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« Reply #12 on: June 11, 2010, 08:34:52 AM »

Is that Dutch system even going to work?

If they run the battery down 50% it would take a 5kW array almost a week to top it off again with perfect sunny days each day.  Within one winter they could find their battery has become the worlds most expensive brick.
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« Reply #13 on: June 11, 2010, 12:07:37 PM »

The killer problem is that if the property is ever going to be sold,  the lack of connection to the grid will devalue it by a lot more than the 21k being demanded.

While spending on renewables does little to enhance a property value  banghead

So a commitment to offgrid only makes sense if you have no plans to sell and / or you want to be gentle on the planet, or you believe that the gov will repay you through FIT's.

Note - the above comments are only my opinion. I will be heartened to be convinced otherwise  Smiley
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mmmmm,  gravy
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« Reply #14 on: June 11, 2010, 12:19:53 PM »

Two points:

1. The house in Holland doesn't appear to have done any energy optimisation.  4200kWh per annum is 11.5kWh electricity a day - what on earth are they using it on?

2. Going off grid, but resorting to a diesel generator is a bit of a cop-out. Unless you are using renewables, wind or solar pV or exclusively a bio derived fuel such as biogas, veg oil or wood gas then running a generator on petroleum diesel at probably 20% overall efficiency is a lot worse than your averge UK powerstation.


Ken
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