Panels on Pergola

[rob1234]

Hi all,

New Forum member here, but I have been reading old posts for the last month with much interest. Like many the electricity prices made me wonder whether now is finally the time to look into solar.

I am in London with a south facing house & garden however have recently had a loft conversion and as such a full dormer which is already at the maximum ridge height so not possible to put solar panels up there. Also not very excited to think of cutting through the new roofing felt system and trust that someone could make it waterproof again!

We do have a large pergola in our garden (see the attached image) which is also next to an outdoor cabinet type unit (it houses a fridge but also has plenty of free space inside). The pergola receives un-shadowed sunshine almost the entire day.



I worked out I could fit 9 x JA Solar JAM60S17-330/MR onto the pergola for a 2.9kw system. I would go with a outdoor rated hybrid inverter in the outdoor cabinet to potentially allow battery later but mainly to reduce the run of high voltage DC. It is a relatively short outdoor run for an armoured cable from there to the main fusebox for the AC side.

I am quite happy to DIY everything that is safe & legally allowed. I have tried to approach a few solar companies to see if they would be willing to handle all the AC side connection, commission the inverter, fill in the DNO G98 and provide me with an MCS cert.
None of them are able to help, with responses ranging from "the panels are really heavy" to "the inverter needs to go inside to be waterproof".

Is this such a crazy idea? I used some calculators to estimate the annual yield (including the really flat angle of the panels) and if I install most of it myself the payback could be as short as 2 years with current electricity prices. I have decided I am no longer interested in being paid for export so MCS cert is not necessary. Could I just connect everything myself and get a sparky to do the new AC circuit and connection? Am I missing something important?

Really appreciate the wealth of experience on the forum, but also have been amazed reading the posts at some of the ingenuity of members' solar setups !

- Rob

[Joeboy]

Welcome onboard Rob, I have a system mounted on a garden pergola. Works well, so well that I ended up doubling in size after fitting it. This had upgrade costs that could have been avoided. We seem to be going thru a little bit of a ground mount renaissance on the forum. My advice would be to look around the garden snd see if you can feasibly go larger from the start. The usual caveat being swmbo's positive input.

I am not up on the legalities but as it's a home CU connection there will be correct certification needed as it all hooks to grid? You would really be looking for a certified 1 man band who'll be willing to work with you if you are doing the heavy lifting so to speak.. Whereabouts are you based (Area)?

[Stig]

Would it be a good idea to work out the wind loading on the pergola? I know this is part of the survey for roof-mount but that's exposed to more wind. Still, it'd be a bit embarrassing it it took off in a storm!

[Stinsy]

Hi Rob, welcome!

That is exactly the kind of project we like around here! You are right (IMO) not to worry about MCS and getting paid for the electric you export. While the prices for consuming electricity have risen spectacularly, guess what has happened to the prices for exporting to the grid? Yep, you guessed it, they haven't budged at all!

You will need to take action to minimise "wasted" energy though. Batteries are the best way to do this, but a solar diverter connected to your immersion is good too.

Horizontal panels work great in mid-summer when the sun is high in the sky and anytime we have bright-overcast conditions.

[smegal]

This is similar to what I'm planning, although I abandoned the Pergola idea as it'd reduce the sunlight in the sunniest part of my garden too much. When I have something to show, I'll update my thread.

I'm going down a similar route of using a sparky to to the AC, then doing the DC DIY.

[rob1234]

Welcome onboard Rob, I have a system mounted on a garden pergola. Works well, so well that I ended up doubling in size after fitting it. This had upgrade costs that could have been avoided. We seem to be going thru a little bit of a ground mount renaissance on the forum. My advice would be to look around the garden snd see if you can feasibly go larger from the start. The usual caveat being swmbo's positive input.

Your setup is exactly what I had in mind with extra panels in the winter. The right hand fence in the picture below gets lovely low angled sunshine in winter mornings and I was thinking I could have a temporary set of 4 panels here in winter when no one uses the garden anyway.

The other seemingly obvious place to mount panels would be on the garden office. There is over 30sqm of roof space however the problem is it gets shading from the tree behind during the mornings when the sun is lower. Possibly I could stick a second string on near section of the roof as it does get amazing sunshine in summer afternoons when the tree isn't interfering.

What I can't seem to figure out at the moment is how to future proof with the inverter. If I go for a larger KW inverter then I need to get pre-approval from the DNO. If I go for a smaller inverter then the maximum wattage it supports via the MPPT controller is also fairly limited for future expandability. The challenge I see isn't that we really need more than a 3.68kw inverter but that to handle the poor sunshine in winter months I would need panels that add up to more than the supported maximum solar connection of the inverter. Do people run sets of equally matched (voltage wise) panels in parallel and just let the inverter pull only what it wants when the sun is blazing in summer?

The other challenge I see is that my locations for mounting panels are not near each other and I would prefer not to have long runs of high voltage DC between them, but rather separate inverters each tied into the AC grid with armoured cable. It looks like the most sensible option eventually will be to ask the DNO for permission to connect a larger system (or combination of smaller systems)

btw, I am in Enfield in north London

[rob1234]

Hi Rob, welcome!

That is exactly the kind of project we like around here! You are right (IMO) not to worry about MCS and getting paid for the electric you export. While the prices for consuming electricity have risen spectacularly, guess what has happened to the prices for exporting to the grid? Yep, you guessed it, they haven't budged at all!

You will need to take action to minimise "wasted" energy though. Batteries are the best way to do this, but a solar diverter connected to your immersion is good too.

Horizontal panels work great in mid-summer when the sun is high in the sky and anytime we have bright-overcast conditions.

Hi - thnx for the welcome,

The plan is to get a few pylontech batteries once I now what kind of generation I get so that I don't go too big and struggle to fill them (we don't have cheap night time rate from the supplier - yet !)
Seems impossible to source any of the Pylontech's at the moment.

Immersion not an option for now as we just have a combi and no cylinder.

Originally the plan was to do it all on a pure cost benefit basis - i.e. not worrying if I still need to import substantially from the grid.
However the more I get into the reading and research I can see eventually I am going to want to see the grid as largely a backup only. It is just very satisfying to be self sufficient.

[Stinsy]

Hi Rob, welcome!

That is exactly the kind of project we like around here! You are right (IMO) not to worry about MCS and getting paid for the electric you export. While the prices for consuming electricity have risen spectacularly, guess what has happened to the prices for exporting to the grid? Yep, you guessed it, they haven't budged at all!

You will need to take action to minimise "wasted" energy though. Batteries are the best way to do this, but a solar diverter connected to your immersion is good too.

Horizontal panels work great in mid-summer when the sun is high in the sky and anytime we have bright-overcast conditions.

Hi - thnx for the welcome,

The plan is to get a few pylontech batteries once I now what kind of generation I get so that I don't go too big and struggle to fill them (we don't have cheap night time rate from the supplier - yet !)
Seems impossible to source any of the Pylontech's at the moment.

Immersion not an option for now as we just have a combi and no cylinder.

Originally the plan was to do it all on a pure cost benefit basis - i.e. not worrying if I still need to import substantially from the grid.
However the more I get into the reading and research I can see eventually I am going to want to see the grid as largely a backup only. It is just very satisfying to be self sufficient.

Batteries are essential for solar to be a sensible idea in a post-FiT world. You can start with a couple of Pylontechs and go from there. Without batteries the sun will shine spilling all your power to the grid, then just as the heating element in your washing machine kicks in a cloud will go across the sun and you'll be using grid power.

There is a 4-6 week lead time on batteries right now but you can order them. Check out https://www.itstechnologies.shop/.

[Joeboy]

Hi Rob, welcome!

That is exactly the kind of project we like around here! You are right (IMO) not to worry about MCS and getting paid for the electric you export. While the prices for consuming electricity have risen spectacularly, guess what has happened to the prices for exporting to the grid? Yep, you guessed it, they haven't budged at all!

You will need to take action to minimise "wasted" energy though. Batteries are the best way to do this, but a solar diverter connected to your immersion is good too.

Horizontal panels work great in mid-summer when the sun is high in the sky and anytime we have bright-overcast conditions.

Hi - thnx for the welcome,

The plan is to get a few pylontech batteries once I now what kind of generation I get so that I don't go too big and struggle to fill them (we don't have cheap night time rate from the supplier - yet !)
Seems impossible to source any of the Pylontech's at the moment.

Immersion not an option for now as we just have a combi and no cylinder.

Originally the plan was to do it all on a pure cost benefit basis - i.e. not worrying if I still need to import substantially from the grid.
However the more I get into the reading and research I can see eventually I am going to want to see the grid as largely a backup only. It is just very satisfying to be self sufficient.

Batteries are essential for solar to be a sensible idea in a post-FiT world. You can start with a couple of Pylontechs and go from there. Without batteries the sun will shine spilling all your power to the grid, then just as the heating element in your washing machine kicks in a cloud will go across the sun and you'll be using grid power.

There is a 4-6 week lead time on batteries right now but you can order them. Check out https://www.itstechnologies.shop/.

Also, a couple of us have hybrid inverters dno approved , mcs certified generally up to the 3.6kW limit. All AC side, grid connected. We then install further panels through a charge controller which feeds dc direct from the further panels straight into the battery stack. This way you are not feeding the grid but feeding your battery stack only. The game then is to utilise all the spare power generated as the further panels will switch.off when the battery stack is full.

[Mr Gus]

I imagine if you got @Desp involved (seeing as he's London centric & in the building trade, & renewables orientated) to do some fag packet math as to age of your pergola, foundation depth of uprights fixings used, timber type & size, whether he'd advise you to add some simple joist strengthening or not (wood, screws, n glue) & do it piecemeal, then hang a string of led outdoor bulbs up to make it appear more cheery & purposeful as to shade beneath by design when it's all done & dusted.

A high ground mount set up in a domestic setting gives you more of a useable outdoor space after all, so worth repurposing imho ..if you are game, & a lovely project of interest documented for likeminded folk.

If Joe, stumps up the details on his joists you have a better idea as a starter for ten as to weight & spec of his panels as a point of comparison for the fag packet math / wind exposure.

@joeboy seeing as your bar+ BQ area is useable, how dry is it joe? did you use a membrane layer to keep drips off you as it just looks like standard rail mount or did you do something sneaky for off season dry storage?