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Author Topic: An off-grid expeience  (Read 6559 times)
heatherhopper
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« on: April 18, 2014, 02:01:52 PM »

Greetings to all

Having taken the off-grid plunge three years ago I have found this forum useful and interesting reading before and since that momentus day. There are precious few on-line sources that offer anything resembling impartial advice. As a fledgling off-gridder I will have had little, apart from confused and frustrated whimpering, to contribute to the forum to date but would like to offer some encouragement to anyone thinking of taking a similar path – that is setting up a comfortable off-grid life for an average household.

The story so far. We acquired a property in our idyllic location – out of the way, of both the maddening crowds and all utilities – 435m up in the North Pennines.  It was somewhat unloved (and mostly uninhabited in the winter). There was power from a newish but dubious sounding 6kw generator with far eastern parentage coupled to a 2.5kw Victron inverter and six 182ah wagon batteries, heat from an excellent but way undersized multifuel stove with back boiler and an erratic and convoluted trickle of water from a “spring”. We determined to pursue the sustainable dream (encouraged by a budget quote of £30,000+ for grid connection). We have progressed (staggered at times) to a position where we are about 95% renewable (just some diesel for static foggy periods and propane for cooking to spoil the status) and are extremely smug as a result. This has not come cheap but complete payback (including allowance for maintenance , repairs and renewal and contribution from tariffs) will be achieved within 12 years. We have also been able to relax from the anticipated power and heating frugality to being positively extravagant in our usage. We have tasted martyrdom but are not hooked on it.

Current system is:
Sunny Island standalone grid consisting 2x2224 SMA SI inverters (master and slave). All generators coupled on the AC side.
2732 AH Rollls Battery bank
2.8 kW ground mounted PV array and 2500 SMA SB inverter
6kW Proven/Kingspan (Grid-tie version) Turbine and 2x3000 SMA WB inverters 9m monopole
9kW back-up generator (Enrogen Lister based)
7x Frequency shift activated sequential diversion loads
25kW Biomass gasification log boiler with 1000 ltr heat store and 2x300ltr DHW tanks in series
1 Wood burning stove and the old multifuel with back boiler blanked - mostly for ambience!
Miles of new wiring and buried pre-insulated pipework (all the above are housed in and around outbuildings)
Various spring fed water storage tanks (with manual back-up from two wells for dry periods) feeding a booster pump for mains pressure delivery

We have lost along the way – the original generator (predictably within two weeks of moving in and before the replacement was ready), a Bergey XL.1 (fully refunded by Bergey) and a lot of hair and naivety.

Spare bits left over if anyone is interested – a 9m CU tower with a top section suitable for a Proven 2.5 (including base plate and gin pole) fitted with an adapter for the Bergey and the Victron inverter which performed admirably until retired.

I won't claim to have installed everything myself since MCS registered installers were obviously required for specific units for tariff qualification. There is a lot you can do yourself though – even with limited knowledge.

Some (but by no means all) things we learned for anyone planning a similar route are listed below. I think smaller budgets, DIY and long term projects are already very well covered on this site so I'm assuming a decent budget and realistic payback expectations – we funded all this from modest savings and very modest income.
1.If using proffesional installers make sure they understand and have experience of off-grid (particularly hybrid systems) and have not simply jumped on the renewable gravy train of the last few years.
2. Oversize everything. Design a system that you think suits your needs and then go back and upgrade everything.
3. If you have decent wind get a big turbine (something like the 6kW or an Evance) as priority – you won't regret the extra power.
4. 48v system as minimum with biggest battery bank you can possibly afford.
5. Install as much well planned (immersions in the bottom) heat storage as possible. A couple of thousand litres won't be too much.
6. Plan your diversion/dump load system carefully. With a big turbine and even modest PV (in the summer) you will not want to waste all that power going open circuit or just heating the shed.
7. Be a little wary of basing your system around SMA even though the gear and support is first class. They have dropped wind inverters and 24v Grid inverters from their portfolio recently and are obviously shifting their market position, to what, who knows.
8. If going for the RHI make sure your EPC assessor knows what he is doing and why. We had no problem with the application (in fact the Ofgem process is very good now they have ironed out the software problems of the first few days). I can, however,  imagine that there will be issues for people with old stone built properties where the status of Cavity wall insulation is not properly assessed and defined on the EPC.
9. If you have space and live in a winter wonderland seriously consider ground mounting your PV – loss of solar before the snow melts/slides off is quite considerable if you don't sweep it off.
10. Make sure you fully cost in maintenance and renewals – be pessimistic about the longevity of the kit.
11. If going for biomass make absolutely sure you can keep your fuel dry – rain and snow in particular finds even the smallest openings. Although we thought we had stored under adequate cover we had real problems with drifting snow and wind driven rain 2012/2013. Although the boiler will cope ok with damp stuff once up to temp there is a massive drop in efficiency and therefore consumption.
12. Also if going for log biomass think of this as a lifestyle change. If you are likely to find it onerous going out a couple of times a day/night to charge the boiler in mid-winter and generally manhandling logs get something else.
13. Be assured that if you get things even half right it will make you unbearably self-satisfied and dinner party invitations will dry up (what a shame eh!).

Hope this has not been too long-winded and that someone might get something useful from it.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
Ted
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« Reply #1 on: April 18, 2014, 03:11:10 PM »

Hi and welcome. Thanks for de-lurking.

That all looks like excellent advice based on hard-won experience.

Can you say what was wrong with the Bergey?
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biff
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« Reply #2 on: April 18, 2014, 05:02:48 PM »


   Welcome to the forum Heatherhopper,
         You have certainly been busy and I am delighted to learn that your venture into renewable energy is proving a successful one.It takes a lot more time than a few weeks to find out if your system can cope with the extremes of different weather and any little tweak or additional work can affect everything else,for the better,,,,or ,,for the worst.
     It is one big long learning curve but you are right about the satisfaction part of things.It does give one a massive big warm glow to get it right.
    I am guessing that the Bergey was twisting the power cables because it did not have slip rings on the Yaw.?
                                                                                    Biff
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« Reply #3 on: April 18, 2014, 05:48:21 PM »

Hello heatherhopper and welcome, look forward to reading your further adventures and experiments.
Are you going self sufficient or cloose too on food as well?
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camillitech
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« Reply #4 on: April 18, 2014, 06:40:44 PM »

Hi there and welcome,

a man after my own heart, AC coupled turbine, proper kit and a decent generator  fingers crossed! Be very interested to here about your sequential dumps and frequency shifting relays. I'm planning the exact same system for my new 'off grid' house based on eight experience with my current one.

I'm thinking of a 2000lt Akvatherm store but can't make my mind up on the number and position of the immersions.

At the moment it'll be 4kwPV 'AC coupled', 800w hydro charging 800ah 48v Rolls, 750w hydro 'AC coupled' and a 2.5kw Proven 'AC coupled' with another 6kw 'AC coupled' Proven to be added at some point. Inverter will initially be 1 SI until the second Proven up and running.

I've a 12kw Lister with 6kw to spare so I was thinking at least one 6kw immersion direct to that, I'd love to know what you do.

It took me over twenty years to come to the conclusion that what you have is just about the perfect 'off grid' system, well done for sussing it in just 3 years  genuflect 

Cheers, Paul
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'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
camillitech
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« Reply #5 on: April 18, 2014, 06:50:44 PM »


 
    I am guessing that the Bergey was twisting the power cables because it did not have slip rings on the Yaw.?
                                                                                    Biff

Bergey's do have slip rings Biff, it's the turbine that Yangzhou Shenzhou copied.
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'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
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« Reply #6 on: April 18, 2014, 07:48:42 PM »

"Be very interested to here about your sequential dumps and frequency shifting relays".

And me , please.

In the next year or so I will also have to go down the AC coupled route and get a decent Inverter that will be the heart.
 
Yea yeah, "Clockman spending money", I here you say, but supplying enough power for a large-ish house and 3 gites will have to be done with direct coupling in other turbines and other PV.
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biff
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« Reply #7 on: April 18, 2014, 09:22:13 PM »

Bergey,s do have slip rings now,
                             But did they have slip rings 5 years ago,? Remember, I am just guessing but I seem to remember a certain Islander saying that Wind Turbines could run fine without slip rings and pointed to an example of a certain Bergey that had been up a few years and ran perfectly with put sliprings.
          Now I could be wrong.I have been very wrong before. whistlie
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camillitech
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« Reply #8 on: April 18, 2014, 09:38:33 PM »

Bergey,s do have slip rings now,
                             But did they have slip rings 5 years ago,? Remember, I am just guessing but I seem to remember a certain Islander saying that Wind Turbines could run fine without slip rings and pointed to an example of a certain Bergey that had been up a few years and ran perfectly with put sliprings.
          Now I could be wrong.I have been very wrong before. whistlie
                                                                 Biff

Wind turbines do run fine without slip rings Biff, Hugh's, Clockman's and Miniwind's all manage just peachy. If a turbine is situated in a place that doesn't suffer turbulence then it shouldn't need them. I know of no person with a Bergey that doesn't have slip rings but then I only know of two people that do have them so you could well be right about the older ones. Personally I wouldn't entertain a turbine without slip rings (well apart from my 'wee baby' God rest her soul ) but NO ONE knows more about small wind than Hugh Piggott and he never fits them.

Cheers, Paul
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'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
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« Reply #9 on: April 19, 2014, 11:57:57 AM »


Be very interested to here about your sequential dumps and frequency shifting relays. I'm planning the exact same system for my new 'off grid' house based on eight experience with my current one.

Cheers, Paul
Those frequency relays are pretty expensive especially as you need one per load.. I'm just in the process of doing a modified version of the Mk2i on the openenergy forum that has frequency control as well as the standard Ct controlled version using an Arduino.
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« Reply #10 on: April 19, 2014, 03:23:36 PM »


Be very interested to here about your sequential dumps and frequency shifting relays. I'm planning the exact same system for my new 'off grid' house based on eight experience with my current one.

Cheers, Paul
Those frequency relays are pretty expensive especially as you need one per load.. I'm just in the process of doing a modified version of the Mk2i on the openenergy forum that has frequency control as well as the standard Ct controlled version using an Arduino.

Hi Nick,

do you have a link ?  it was more the immersions and values I was interested in as I'm not electronically competent but I'd be very interested in seeing what you're up to.

Cheers, Paul
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'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
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« Reply #11 on: April 19, 2014, 04:36:53 PM »

The commercial one I have seen is http://ambercontrol.com/index.php/amber-switch which is about £90 +vat each. The Arduino dump is at http://openenergymonitor.org/emon/node/1912.

I don't have a link to what I am doing as all it is just a modification of the actual program so that it looks at the mains frequency rather than the current transformer for its sensing. As I am going on sunny backups I am going to need both types of sensing, one for when grid connected and one for when either the grid is down or I turn it off.
I also need to have Ct's on the supply from the backups to the Auto switch box so my dump loads don't come on unless the batteries are charging or charged! It starts getting very complicated and until its all set up I don't know if its going to work- It will in the end through!
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heatherhopper
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« Reply #12 on: April 20, 2014, 10:05:13 PM »



Can you say what was wrong with the Bergey?

I was afraid someone might be curious. It is a very long story but the short answer is – no we never did find out what the root problem was. As background it is important to understand we have a very windy, gusty site.
Below is the shortened (yes shortened) version
Bergey installed strictly according to the manual Feb 2012 on 9m Proven type tower with suitable bore extension piece adding about another 1m of height. This turbine was selected because there is one just down the road that has been performing fine for some 6+ years (and it suited our budget).
Some strong gusty winds (25+ mph, gusting to 50+) in first few days. Appeared to overspeed and/or suffer blade flutter at anything approaching and above furling speed (30 mph) but furled ok. Also did not seem to engage “slow mode” as it should - a feature of the controller system which slows the rotor when batteries are approaching nominal voltage (default setting 28.1v) – and was subject to breaker trips.
After about10 days (and some lighter winds) it developed a “knocking” noise and lateral movement of the head accompanied by a shake at the tail and nacelle union. Taken down and blade assembly castle nut found loose but with split pin in place (this assembly was complete as delivered). After consultation with distributors reassembled by the book and returned to operation.
Same symptoms developed quite quickly. Taken down and Distributors sent a replacement head and we also shortened the tower extension piece
Returned to operation but overspeed/blade flutter still apparent and breaker trips persisted.
By now liasing directly with Bergey.
Through the summer (lighter winds note) various things tried:
Much fiddling with charge settings etc on both Bergey controller and Sunny Island.
Resistor sent from Bergey and fitted before their controller.
Larger breaker fitted in controller (this was a success in so much as the breaker trips stopped).
Dump loads (AC side) fitted, reconfigured and generally messed around with.
New 3” shorter blade set fitted.
Overspeed/blade flutter problem and inability to engage slow mode properly persisted throughout. I can not stress the noise/vibration enough – it could be distintly heard/felt some 1.5 miles distant.
Bergey certainly seemed to be trying to sort the problem but it is worth reflecting that they were phasing out the XL.1
December 23  in sustained high wind developed a distinct growl and subsequently stopped delivering any power.
After negotiation with Bergey agreed a full refund and the head unit was returned to them.
Although there were some obvious faults the real cause of the problems are still unkown – whether Bergey have investigated the returned bits we don't know.
For the record – yes it did have slip rings, showed a fair bit of wear when the unit came down.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
heatherhopper
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« Reply #13 on: April 20, 2014, 10:11:46 PM »


Are you going self sufficient or cloose too on food as well?


Full blown self sufficiency is probably a bit beyond us but we do talk wistfully about it and the poultry are multiplying (or would be if we didn't like omelette and home baking so much) and the veg patch gets bigger every year – four months worth of spuds last year! Short growing season up here though.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
heatherhopper
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« Reply #14 on: April 20, 2014, 10:22:48 PM »

Be very interested to here about your sequential dumps and frequency shifting relays. I'm planning the exact same system for my new 'off grid' house based on eight experience with my current one.


A work in progress and I think best use of what I've got rather than what I would like but currently:
5x Din rail mounted relays. All with 25a contactors.
Three in the outbuilding.
One Econnect type DILC controlling 1kW immersion half way up the main DHW tank (boss position reflects initial expectation of limited dump potential). This is set around 50.4 hz and has a random delay timer.
Two Eltime frequency protection relays with delay timer function set to 0. First set at around 50.6 hz and controlling a 1kW immersion half way up the heat store (again boss position reflects initial expectation of limited dump potential), second around 50.8 hz controlling 3kW immersion in the bottom of the feeder DHW tank (installed for increased dump potential).
Two in house
Eltime relays with timer set at minimum (about 2 sec), one at about 50.12 hz and one at about 50.14 hz. Both connected directly to several sockets on isolated sections of old house ring. Usually have a 1kW convector on the first and a 3kW oil radiator on the second.
2x Econnect plug type DILCs with random delay timers and set to 50.4 and 50.8 hz. Usually have these connected to 1 & 0.7kW oil radiators and just move them wherever we want some extra or pre-heating.
All the above settings are from memory – I've mislaid the Econnect dip switch settings list and the Eltime pots settings are not very precise and required two people and much semaphoring to set!
Immersion thermostat settings are near max in the heat store which is in practice around 85c @ 3.5 bar at the top of the tank on trip. Note that the layering system of the tank is ineffective if there is no forced circulation. 56c in the DHWs.
Appreciate that some of this might seem counter-intuitive and it only the latest of many different configurations. It has worked very well this last autumn/winter – keeps the PV on, turbine loaded and puts the heat pretty much where we want it. Anyone who has watched the frequency shift of a SI inverter with large wind input might have the best insight into the plan.
I intend to replace the heat store immersion with a 2kW when the weather warms up.
It is true the relays aren't cheap but there are plenty available – apart from Eltime ABB, Hobut etc all have their own version. I believe the Amber control is the newer version from the same manufacturer as my Econnect and made specifically for renewable industry but it does the same job as a standard frequency protection relay.
PLC control (with a pwm output) is the way to go if you can.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
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