Pure Planet solar panels and battery pilot - pre-install questions and info

Pure Planet solar panels and battery pilot - pre-install questions and info
  • Community Manager
  • 7636 replies

We’re running a pilot to test installation of rooftop solar PVs and storage batteries with bp Lightsource Labs.

The partnership will also make use of Lightsource Labs’ home energy management technology – Tribe – and cloud-based Virtual Power Plant (VPP) platform to monitor and optimise live energy generation, storage and usage. 

Using the systems as part of a VPP means that Pure Planet can aggregate each individual storage system together into a ‘power plant’ and operate them to reduce the cost of supplying electricity and help balance the grid. We think VPPs could play an important part in getting the UK to net zero.

I’m one of five participants taking part in this first phase of the pilot. We’re all part of the Pure Planet team and we’re also the first ‘guinea pigs’ to experience the process. So we’re at the very start of the first phase of a two-year pilot to test the hardware and service needed for our Members to generate and store their own renewable electricity at home.

We’ll be looking to expand it to involve Pure Planet Members soon and if you’re up for helping out, add a reply to this thread announcing the pilot and partnership.

Scaffolders at work

As the scaffolding goes up and the panels are fitted, I thought it might be of interest if I shared my experience of the pre-install questions and preparations. I’ve already had some questions posted in a community shout-out which I’ll attempt to answer here. But if you’ve got any more questions about the pre-installation and installation process, please do add them in the replies below!

I’m planning to write a separate post about using the technology, and the app, and so on. And another one about how to export my energy to the grid, and how it’s affected my energy bills.

 

Questions I had about solar rooftop PVs and batteries

I guess my first question was…. How does it actually work? Here’s the science! 

PV systems use cells to convert sunlight into energy. The PV cell consists of one or two layers of a semi-conducting material,  usually silicon. When light shines directly on to the cells, it creates an electric field across the two layers and creates  electricity to flow.

The greater the intensity of light, the greater the electricity that is generated. The solar panels gather the electricity and this is then converted from ‘direct current’(DC) electricity to ‘alternating current’ (AC) electricity via an inverter switch. 

Once this has been converted, you are ready to use the electricity or export it back to the grid. 

 

How much energy will I get from solar panels?

For the purpose of this pilot, I’m a lucky, lucky boy because basically I’m getting the whole lot for free. A big perk of working at Pure Planet. If I were to pay for the solar panels, battery kit this would cost me somewhere around £8,000 including labour to put up the scaffolding, install the panels, connect it to the battery and connect it to an inverter, to the meter and mains.

Now, £8,000 is not a small amount of money. We had a great question from @ChrisH  who asked if Pure Planet would explore means of financing this for Members, such as options to lease panels rather than buy them, or if the panels could actually be owned by Pure Planet used by the Member, and excess energy not needed Pure Planet could then sell back? This is definitely an area we want to explore further.

@G4RHL  asked if the panels provider can give you a guarantee of the amount of energy they’ll produce. 

When signing up for PVs, you get a ‘proposal’ of predicted system performance. This is based on the size of your roof, how many panels it’ll hold. It’ll be estimates, of course, because the amount generated depends on the weather! 

My roof has space for 12 panels. Given the angle of my property, my PVs will be most active in the mornings. My estimated output based on the number of panels is 3.24kWp, or kilowatt ‘peak’.

Estimating the total energy produced for solar panels uses a calculation of 3 factors

  • kWp (total size of solar panels installed)
  • Kk (predicted amount of sunlight for your postcode)
  • SF (predicted amount of shade, which changes depending on month and angle of sun and on elements which might block the sun, such as chimneys.) This diagram is useful to visualise it:
Sunpath chart

The calculator is kWp x Kk x SF

For me, that works out as 3.24p x 935 x 1

Total: 3,029 kWh per year.

Which is about half of my annual electricity bill! 


How much CO2 will I save?

Of course, because I’m on supply with Pure Planet, my energy is already renewable, even if it does get mixed up with dirty fossil fuels on the grid.

With solar PVs at home, there’s 3,029 kWh of pure solar power. On average renewable energy saves 200g of CO2 per kWh, so my home PVs will save just over 605kg of CO2 per year. 

 

Does the power produced change over the years?

This question was asked by @G4RHL  and it’s one which I had wondered about, too. The panels’ energy generation is expected to drop by about 1 per cent every year. 


Do the panels need to be maintained?

Good questions from @Duppy here. How long are the panels and storage expected to last before replacement, and is there any ongoing maintenance required?

The hardware itself has few moving parts so won’t need lots of maintenance. But once every 10 years you need to replace the inverter switch which converts DC to AC. They cost about £500.

It’s recommended that you clean your panels now and then.

One thing that is worth mentioning is whether you need bird protection netting. This was an optional extra and it’s suggested that you do get this if you have lots of birds near your home. As we’ve got loads of birds in our garden, including starlings who nest in the roof every year, we decided to pay for this extra, which was £400.

 

Do they need to be weather proofed, and how do they affect home insurance?

These questions are from @25 quid  and the question about home insurance was also asked by the PP team taking part. You definitely should tell your home insurance company about the solar PVs (if the worst should happen you’ll want to claim for them) but there was no extra added to our premium. Other people’s experiences with this may be different, of course.

The panels are already weather proofed, and come with a 10 year warranty.

 

During the installation, who does which bit?

As we got closer to the installation, I then wondered how many different ‘parties’ are involved in this? The answer is four... at the moment. 

  1. Pure Planet, who supply my energy from the grid and who I will also export energy back to
  2. Coolpower Electrical. The solar PVs retailer and installers. They also sell the battery, inverter and the leads.
  3. Scaffolders. Will be included in the installation quote and of course depends on how big your home is.
  4. Lightsource Labs - Run the technology, the ‘Tribe’ box which speaks to the app and shows your how your energy is being generated, used and exported.

 

Does the weather affect installation? Will rain delay it? 

Typical, we had the most amazingly sunny spell just a week before the installations, and then along came the classic British Summer…. And it rained. This didn’t delay things though. I suppose it’s a question of common sense. If there was huge storm with lightning, the installers would probably want to wait for it to pass.

 

How will my EV work with this new system?

A big question for me, and I’ll do a separate post when I know more. My EV is, essentially, another means of storing energy. I could, I think, charge it up during the day from solar energy, and then empty it by exporting the whole lot to the grid in the evening. And repeat the following day. Of course I’ll need to be certain that I don’t need to actually drive anywhere. :thinking:

 

Questions I was asked by the installers

All the pre-install questions were about my property. I was asked to draw an outline my roof over a map, so that Coolpower Electrical was able to get a general idea of which direction the roof faces, and how many panels it can accommodate.

Then I had to send them several photos of my electricity meter and fuse box set up, photos of areas (such as the garage) which could be used to house the battery, which needs a bit of space for heat circulation, and any other info that was relevant, such as my EV charger. 

As this ‘ticked the boxes’, the next step was a site visit, so that they could confirm it all, talk me through the process, and also take more photos of the roof/walls for the scaffolders.

All this info was used to form the contract, and there was a final discussion about the bird protection option.

(An aside. Earlier this year I took part in an unrelated Zoom call with a company called Solar Streets which offers bulk discounts if it can sign up 50 or more properties from one town in one hit. They asked me the same questions, and also wanted me to draw my roof on a map, so it feels like this is all quite standard now. )

 

That’s my little write-up about the solar PV and battery installation process, before and during. I hope it’s useful for anyone wondering about this stuff! Coming soon to a Community near you: How to use the tech; How to do smart export guarantee and send energy I don’t need back to the grid; How does my EV fit in with my home solar and battery set up.

 

Read more


24 replies

Great round up @Marc.

What’s a kWp? You say “My estimated output based on the number of panels is 3.24kWp

My original question was about how the panels were fixed to the roof and how that might impair the weatherproofing of the existing roof?

Thanks

Great round up @Marc.

Thanks @25 quid 

 

What’s a kWp? You say “My estimated output based on the number of panels is 3.24kWp

It’s kilowatt peak. Good shout, I’ve added this.

 

how the panels were fixed to the roof and how that might impair the weatherproofing of the existing roof?

Frames (or ‘rims’) are connected via brackets to rafters. The panels then slot into the frames/rims. I was informed no impact on weather-proofing.

Aha, kW peak 👍

Hmmm, fastened to rafters. A hole through the tiles or slates. No impact on weatherproofing. Hmmmm. Plus the frames place weight and wind-load on the tiles (slates) potentially causing cracking. Hmmm. 🤔

Sceptical face. Not sure I fully trust the long-term seal on that. But maybe others have evidence…

It’ll be right! 😊 

Fascinating 🖖

Looking at that formula, SF sounds more like Sun Factor than Shade factor. Maybe it should be (1-SF where SF is shade factor). No shade=full output. Oh I’m annoying myself with this reply!! 😉 

Pedantically it’s back to front, just like Air Quality Index. Higher number is lower quality, so it’s really a pollution index not a quality index.

 

 

I’ll get mi coat!

 

 

 

 

 

 

 

Thanks Marc. Constructive and helpful.
 

Nice to see the degradation rate has now been improved. The important bit for many will be the payback rate. I read that it can be 12 to 18 years or longer. In some senses that is fine if the panels last for 20 to 25 years but the last thing one wants to do is find you have just got your money back and then you have to replace. You are better placed where you live and payback rate may be less than where I am. However, just doing a raw circulation if it costs £8000 to install it would be at least 16 years before I get my cost back and probably more because we have less sunlight and electricity prices will go up as well. So it is a long pay back time.

In my case I am more likely to be below the turf and never get the capital cost back.

One other question is the cabling. How is it routed? Is it unsightly? I assume the inverter is in the loft out of the way? But somewhere there is a connection to the incoming supply which could result in some messy wiring and equipment.

A final question, which you may have to ask your installer. Is the equipment screened or filters put in place to stop electrical interference - mainly from the inverter I believe? In the early days some interference was common.

But, many thanks for this.

Great round up @Marc.

What’s a kWp? You say “My estimated output based on the number of panels is 3.24kWp

 

Does 3.24 kilowatt peak seem high or low to you @25 quid ? Were you expecting more or less or did it sound about right?

Does 3.24 kilowatt peak seem high or low to you @25 quid ? Were you expecting more or less or did it sound about right?

I have no experience, but sounds impressive and reasonable. As to how it compares to other installations, I have no idea.

I guess that’s a nice amount. It’s basically 13A and Watt/what the most powerful domestic appliance could use. So if it’s sunny — free energy! Just don’t put your kettle, Jacuzzi, hairdryer and oven on at the same time.

Current status :relaxed:

 

Userlevel 7
Badge +9

Ooh, can one explain what exactly all the figures mean @Marc ?

 

Ooh, can one explain what exactly all the figures mean @Marc ?

The screengrab of the app tells me that panels are generating 3.4kW of elec, the house is using 0.967 so the reminder is topping up the battery. 

As things stand I’m not taking any elec from the grid - that’s the one with 0kW.

If the sun keeps shining, and the battery gets full, then it’ll switch to exporting to the grid.

I’m planning on doing a new post on all this stuff @Angelabikerbabe TBH I’m still working it all out. I need a few days to get my head around it all!

Userlevel 7
Badge +9

Oh thanks @Marc , how fantastic!! Free electric....I want one! 

Userlevel 7
Badge +8

Oh thanks @Marc , how fantastic!! Free electric....I want one! 

Ah!, but is it free electric? especially if it costs approx £8000 to install?

 

It’s the same as free beer. You still need the brewery. 😉 

But what in life is free? There’s a thread opportunity all in itself!!

What’s the capacity of the battery @Marc? How many kWh? It looked quite small, but is it enough to get you through the evening?

One other question is the cabling. How is it routed? Is it unsightly? I assume the inverter is in the loft out of the way? But somewhere there is a connection to the incoming supply which could result in some messy wiring and equipment.

A final question, which you may have to ask your installer. Is the equipment screened or filters put in place to stop electrical interference - mainly from the inverter I believe? In the early days some interference was common.

But, many thanks for this.

Hi @G4RHL 

There’s cabling from the PVs, into the roof, then down the wall, to the inverter/battery set-up which is in the garage. I believe some have this all in the loft, but I’d imagine it would be quite a feat to lift it up there.

Then there’s more cabling between the meter/fuse box and the battery.

They’ve done a good job on ours, the cabling between meter and battery goes through one room, but it’s contained in a white case that runs along the skirting. Plus there’s a chest in front of it.

Re interference - this hasn’t come up at all. Not heard any, either.

What’s the capacity of the battery @Marc? How many kWh? It looked quite small, but is it enough to get you through the evening?

Good question @25 quid It’s 5kW capacity, and the output is 2.5kWh. 

There are larger batteries - eg a 10kw battery with an output of 5kWh.

But! I’m told that the average household demand is less than 2.5kW about 95% of the time.

So far the only time I felt that the battery might be a bit small for me was when I plugged in my Leaf with its 7kWh charger. Apart from that, it feels like it’s plenty of battery for us.

Perfect! I think you’ve got your units back to front:

Probably 5kWh capacity, and the output is up to 2.5kW. 

Yeah, should keep you going for a fair few hours of normal usage around and about the house. Does the system empty the battery into the grid ever? I think I asked that question in another thread once upon a time.

One other question is the cabling. How is it routed? Is it unsightly? I assume the inverter is in the loft out of the way? But somewhere there is a connection to the incoming supply which could result in some messy wiring and equipment.

A final question, which you may have to ask your installer. Is the equipment screened or filters put in place to stop electrical interference - mainly from the inverter I believe? In the early days some interference was common.

But, many thanks for this.

Hi @G4RHL 

There’s cabling from the PVs, into the roof, then down the wall, to the inverter/battery set-up which is in the garage. I believe some have this all in the loft, but I’d imagine it would be quite a feat to lift it up there.

Then there’s more cabling between the meter/fuse box and the battery.

They’ve done a good job on ours, the cabling between meter and battery goes through one room, but it’s contained in a white case that runs along the skirting. Plus there’s a chest in front of it.

Re interference - this hasn’t come up at all. Not heard any, either.

Thanks @Marc That has nailed the coffin lid for me so far as solar is concerned. My garage is detached - one metre away from the house. Sounds like and untidy appearance I would not want. Despite the fact of course that I remain unconvinced of the advantages, other than being greener, but then it is at some cost to the consumer.

Where you might get interference, or your neighbour might, is on the TV. Now we have flat screen TVs with LEDs and such it is not such an issue but with the old cathode ray tube job it might be. The problem would not be your installation but your or your neighbour’s TV, although you might have a problem convincing him its his TV!  But it would be! Manufacturers used to leave out a filter or two when making TV sets. It meant not all signals could be screened. They did it because it saved them £10 and if you multiply that but the number of sets made its a lot of money. If manufacturers can get away with it they will!

Thanks @Marc That has nailed the coffin lid for me so far as solar is concerned. My garage is detached - one metre away from the house. Sounds like and untidy appearance I would not want. Despite the fact of course that I remain unconvinced of the advantages, other than being greener, but then it is at some cost to the consumer.

I think it’s our challenge to convince you otherwise, and to make it attractive from a price point of view, too @G4RHL :wink::relaxed:

 

Userlevel 7
Badge +9

Oh thanks @Marc , how fantastic!! Free electric....I want one! 

Ah!, but is it free electric? especially if it costs approx £8000 to install?

 

😭

Oh thanks @Marc , how fantastic!! Free electric....I want one! 

Ah!, but is it free electric? especially if it costs approx £8000 to install?

 

😭

It never becomes free. It seems it will always cost more to instal the panels than what you save. Unless you move to Australia. The most economical route is still a gas boiler despite its lack of greenness. There needs to be an alternative to gas, whether hydrogen or natural, that is cheaper. There isn’t. But the government could make it so.

I’d definitely like to be involved in the Pure Planet solar PV panels and battery pilot👍

Hi,

Is it possible to provide an example of the map that is requested to be drawn by the installers, of the roof?

Also, is it possible to install these on flat roofs?

 

Thanks

Hi,

Is it possible to provide an example of the map that is requested to be drawn by the installers, of the roof?

Also, is it possible to install these on flat roofs?

 

Thanks

Hi @eorinbehara 

For this pilot, the installers came over to mine, physically, to take a look. But I did previously make an enquiry into solar panels and I was asked to use this online tool called ‘map developers’ which allows you to draw on a Google map, and save/send it. 

 

Flat roofs should be fine. In fact they’re likely to be easier to install. They’d need a frame to hold them at the optimal angle though.

Reply