Should I go off-grid?

Krakkkers

I pay way less than £12 for internet, phone, etc, plus unlimited TV, movies and sport.
Stop obsessing about cutting and look for the deals.
Some years i make a net profit from those deals.

Pile_o_stone

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? 

Pile_o_stone

michaels said:

I'm thinking that if the plan is for PV to support all your consumption throughout the year then you should orient them rather than for maximum annual generation (35 degrees, S facing) but instead for max December generation (almost vertical S facing? and as high as possible to avoid shading).  Lower total annual generation but max December generation.

I was watching an off-grid couple on youtube who have built a large array of solar onto a frame attached to a shipping container. They spent a lot of time and effort building the frame so that it can be reoriented vertically for max solar gain. In doing so, I felt that they made the frame flimsier than a fixed frame would have been. As they live in the USA in an exposed mountainous region, I wondered if the increased solar power outweighed the potential for the loss of part or whole of array during a bad storm (and the loss of the energy).

It would be interesting to know just how much power someone would lose with a fixed, optimised December orientation and whether that loss would actually be missed. I'd imagine that someone who is off-grid would size their solar to provide as much of their electricity needs as possible in December, and so as the seasons move to Summer they would have an over-abundance of energy generate anyway, even if there was a loss due to winter orientation.

Martyn1981

Hi POS, I saw that episode, and thought exactly the same. Great idea to incorporate the shipping container as PV base, and use it as the plant room, but winter optimisation would still deliver more than enough for the summer. As you say, I thought the additional pitch variability added a cost, complication, and weakness, that wasn't worth the effort, and the money might have been better spent on upping the panel efficiency a smidge. But great what they've done.

HertsLad

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? 

No problems that I am aware of. Even if the house gets a bit damp in the winter (and I'm not convinced it does) then presumably it dries out each summer.

HertsLad

Pile_o_stone said:

It would be interesting to know just how much power someone would lose with a fixed, optimised December orientation and whether that loss would actually be missed. 

My 6 panels are in a semi fixed position but at various angles and tilts so some panels pick up most sun in the morning and some in the afternoon. It has worked well from April to October, and counting. I was going to move things around so all panels can be rotated and tilted, to approach a situation where all 6 panels will be facing the sun from dawn until dusk. Maybe I still will but, as at late October, there is still plenty of energy for my minimal needs. The sun is lowest c21 Dec.  Is the position of the sun the same a month before and a month after? Like on 21 Nov and 21 Jan. I have no doubt that rotating and tilting the panels will increase available energy by a significant amount - perhaps 50% of more.

QrizB

Pile_o_stone said:

It would be interesting to know just how much power someone would lose with a fixed, optimised December orientation and whether that loss would actually be missed. I'd imagine that someone who is off-grid would size their solar to provide as much of their electricity needs as possible in December, and so as the seasons move to Summer they would have an over-abundance of energy generate anyway, even if there was a loss due to winter orientation.

A bit of experimenting with PVGIS, assuming a 1kWp array facing due south somewhere near Oxford (latitude 51.8), I get:

• Slope 40 - 38kWh Dec, 1017kWh total (this was the PVGIS "optimum" slope)
  
• Slope 45 - 40kWh Dec, 1015kWh total
• Slope 50 - 41.5kWh Dec, 1007kWh total
• Slope 55 - 43kWh Dec, 993kWh total
• Slope 60 - 43.7kWh Dec, 973kWh total
• Slope 65 - 44.3kWh Dec, 948kWh total
• Slope 70 - 44.7kWh Dec, 917kWh total
• Slope 75 - 44.7kWh Dec, 881kWh total

It seems like the optimum slope for December generation is around 70 degrees (roughly 20 more than the latitude) where you generate an extra 17.6% in December at the cost of losing 13.4% of total generation across the year.

zeupater

HertsLad said:

Pile_o_stone said:

It would be interesting to know just how much power someone would lose with a fixed, optimised December orientation and whether that loss would actually be missed. 

My 6 panels are in a semi fixed position but at various angles and tilts so some panels pick up most sun in the morning and some in the afternoon. It has worked well from April to October, and counting. I was going to move things around so all panels can be rotated and tilted, to approach a situation where all 6 panels will be facing the sun from dawn until dusk. Maybe I still will but, as at late October, there is still plenty of energy for my minimal needs. The sun is lowest c21 Dec.  Is the position of the sun the same a month before and a month after? Like on 21 Nov and 21 Jan. I have no doubt that rotating and tilting the panels will increase available energy by a significant amount - perhaps 50% of more.

Hi

On the rotation & tilt ... are you looking at doing this manually multiple time a day, or considering building/investing in an automated tracker?

Z

HertsLad

zeupater said:

On the rotation & tilt ... are you looking at doing this manually multiple time a day, or considering building/investing in an automated tracker?

Semi-manually, perhaps 3 times a day. So the panels will be in one position overnight and morning until around 10am GMT. Facing south east. Then moved (move 1) to a mid position from 10am to 2pm . Facing south. Then moved (move 2) to pick up late day sun from 2pm until dusk. Facing west . At dusk, I will move them back to the start.

I say semi manually because, if it's not too difficult, I may add a motor to handle the tilt adjustment. But I will push buttons, rather than it being automated. The adjustment from facing south east, through south to west will be manual, although it's an interesting idea to try automating everything, One issue is that, when I go away on holiday, the panels won't move, so if there is a very observant potential burglar around, it could be a security risk. 

ABrass

HertsLad said:

zeupater said:

On the rotation & tilt ... are you looking at doing this manually multiple time a day, or considering building/investing in an automated tracker?

Semi-manually, perhaps 3 times a day. So the panels will be in one position overnight and morning until around 10am GMT. Facing south east. Then moved (move 1) to a mid position from 10am to 2pm . Facing south. Then moved (move 2) to pick up late day sun from 2pm until dusk. Facing west . At dusk, I will move them back to the start.

I say semi manually because, if it's not too difficult, I may add a motor to handle the tilt adjustment. But I will push buttons, rather than it being automated. The adjustment from facing south east, through south to west will be manual, although it's an interesting idea to try automating everything, One issue is that, when I go away on holiday, the panels won't move, so if there is a very observant potential burglar around, it could be a security risk. 

You're not going to get 50% more. Active two dimensional trackers might get you 35% more power, but that's with them constantly optimising the angles. With manual adjustment twice a day you aren't going to be nearly that good. At a guess you're likely to see maybe 20% more. Which is nothing to sniff at, but managing expectations is always good.