Should I go off-grid?

HertsLad

ABrass said:

You're not going to get 50% more....at a guess you're likely to see maybe 20% more. Which is nothing to sniff at, but managing expectations is always good.

My 50% guesstimate was based on a comparison with having all my panels bolted to my house roof facing SE. As it, moving from the summer positioning to moving them three times a day for winter will probably lead to a 'significant' increase in available energy. I can't measure it. In summer, the extra energy will be there to use if I can think of an opportunity to use it. In winter, it will be  the same but with a much lower maximum ceiling. And as a hedge against any really dull days when it remains possible there may not be enough energy for my essential needs, i,e. fridge, phone recharging, charging batteries for my house lighting, and 15 mins of electric blanket use each night. Although I can always use a hot water bottle with water heated on gas if the batteries drop too low.

Reed_Richards

Pile_o_stone said:

HertsLad said:

I am perfectly comfortable, even in my unheated house at 2C. It's hard to describe. With the layers I wear, I feel like I in the middle of a bubble of self-generated warmth (no electric pads).  

With so little heat inside your house, do you have any problems with damp and mould? 

Assuming the structure of the house is sound then damp and thence mould come from drying clothes indoors, washing (particularly showering), breathing and perspiring, maybe house plants.  If a house is kept at 2 C then you will most likely not attempt to dry clothes indoors and the range of house plants you can grow will be limited.  Much of the time you should be able to keep your house very well ventilated without fear of making it any colder than it already is.   

zeupater

HertsLad said:

ABrass said:

You're not going to get 50% more....at a guess you're likely to see maybe 20% more. Which is nothing to sniff at, but managing expectations is always good.

My 50% guesstimate was based on a comparison with having all my panels bolted to my house roof facing SE. As it, moving from the summer positioning to moving them three times a day for winter will probably lead to a 'significant' increase in available energy. I can't measure it. In summer, the extra energy will be there to use if I can think of an opportunity to use it. In winter, it will be  the same but with a much lower maximum ceiling. And as a hedge against any really dull days when it remains possible there may not be enough energy for my essential needs, i,e. fridge, phone recharging, charging batteries for my house lighting, and 15 mins of electric blanket use each night. Although I can always use a hot water bottle with water heated on gas if the batteries drop too low.

Hi

I tend to agree with ABrass's assessment that 50% is likely a little optimistic, especially so if manually adjusted, which is something I'd guess would get a little tedious over time and therefore missed at an ever increasing frequency, as a number who have tried it before will attest ....

I've just pushed some test data through PVGIS for a system chosen at random somewhere in central England, comparing a South facing fixed roof setup with one mounted on an automated 2axis tracker and the difference would be ~32%.

The issue you may find is that any ground mounded system could be more open to shade from trees etc  early/late in the day, especially so in the winter, therefore unless you have open horizons, swinging panels on low mounts to capture more direct sun may not result in the level of performance increases expected.   

Anyway, if this is a route you're going down, make sure that the mounting is sturdy and well anchored to the ground, taking great care to ensure that the panel adjustments are able to be securely locked into position every time ... I've seen a number of tales elsewhere which haven't ended up too well for the health of what are relatively fragile panels ..

HTH - Z

Martyn1981

Hello Z. I recall someone building an automated dual axis tracker on the old Navitron site. I think they gained about 20-25%, v's the monthly figures from other members, which seems in line with your estimates.

That was a constant tracking system. This dates back to about 2011/12 for the build, when panels were much more expensive. Now that PV is so much cheaper, to save on complexity, build cost, and as you say, potential fragility, it's probably better to optimise for winter orientation, and just add 25% more panels.

HertsLad

I have been working on a mast of sorts (made of wood) for a wind turbine which I bought on eBay. Last night, the first half decent winds for some time were forecast and it's frustrating not being to try it out. On the other hand, there hasn't been a time (since April) when a wind turbine or any other source of energy would have been required to contribute a single watt. I have reduced my electricity consumption to such an ultra low level that the battery bank remains almost fully charged at all times, including early morning before the sun re-appears. As for thinking I may need a steam turbine, that was completely OTT. So, if I return to my original question: "Should/could I go off grid?" The answer is a resounding 'yes' Far more people should try it!

That's subject to two conditions, however. First, being able to get through the winter as easily as I have got this far. Second, my energy provider sticking to their promise to refund the standing charge and not expect me to pay any more. 

A further realization is that my battery bank is probably too large - lead acid batteries with a usable capacity of over 6kwh. As per the original plan, I will see how long the lead acid batteries last before they need replacing. My hope is at least 10 years. If I purchase a further set, I would need to re-assess if lithium-ion would be a better investment. At present, I doubt it.

Exiled_Tyke

I would suggest that you see how one winter goes before disconnecting.  Ok, so my situation is very very different but my usage pattern and dependency on my battery changes massively as winter progresses.  

If you have far more battery capacity than you need, presumably they will last longer as they won't be recycling as hard? 

HertsLad

Exiled_Tyke said:

I would suggest that you see how one winter goes before disconnecting.  Ok, so my situation is very very different but my usage pattern and dependency on my battery changes massively as winter progresses.  

If you have far more battery capacity than you need, presumably they will last longer as they won't be recycling as hard? 

Thank you for raising some interesting points.

So far so good for me in Hertfordshire only 1 month away from the shortest day of the year c21 Dec. What I mean is that, even with a succession of cloudy days, including today, there has been enough power coming from just 6 solar panels to completely recharge my batteries. But I think graphs I have seen on this forum suggest solar energy falls further in January and February. Is this because cloud cover tends to become even more dense 'after Christmas'? Or why? I would have thought energy would be increasing as the days slowly become longer after 21 Dec.

Good point about a larger battery bank being placed under less strain. i will think twice before scaling it back.

HertsLad

Deleted_User said:

We've got 5 years of wood stored and the ability to accumulate free wood and season it ourselves - we're in a rural area.

We have 2 generators...

So in total we have around 7kw storage and 5kw output...

All thoughts, suggestions, comments etc very welcome. We are new to this. And not as hardcore - I like my home comforts!!!!

It sounds like you have a great set up, especially being able to store so much wood.

I am hesitant to ever power up my single, small 700w generator because I fear the cost of the pertrol. I only have it for emergency use. I calculated it would not need to be run for many hours before it is more cost-effective to be paying for mains electricity (standing charge and usage elements).

Screwdriva

HertsLad said:

I really don't think any of your suggestions apply to me, Krakkers. You imply my cuts make me uncomfortable but that's incorrect. I am perfectly comfortable, even in my unheated house at 2C. It's hard to describe. With the layers I wear, I feel like I in the middle of a bubble of self-generated warmth (no electric pads). Try it and you'll see!

As for internet costs, there's no way I think I could reduce them below the £12 I currently pay. And that includes line rental for the phone, in effect.  

Well said, HertsLad. Some of us often forget that there is no panacea when it comes to sustainability. 

HertsLad

I returned from a week away yesterday to find all but one of my six solar panels covered in snow. I suggest that's another reason why it may be best to adopt a vertical orientation.  I was very pleased to see that the system voltage was still 25.5V, probably due to one vertical panel being clear, combined with ultra low current draw from a 24V fridge in an unheated house. The house is now below the mid temperature for a fridge! 

This morning I cleared snow from two more panels. The system has now reached a float voltage of 29V so I was lucky.