Earth Notes: KEHS talk: Fresh Home Solar PV Install in Kingston (2024)

Updated 2024-05-24 12:41 GMT.
By Damon Hart-Davis.
Kingston Efficient Homes Show 2024 small talk by Alan F.
KEHS2024 3 RBK
Alan F delivering one of the "small talks" at KEHS 2024, explaining his fresh new solar PV installation, with battery, and solar diverter to hot water, and a chunk of wide-ranging discussion afterwards.

Many thanks to Alan F for the slides and for delivering the talk!

1501s "KEHS2024 fresh solar install" (captions) Uploaded . Downloads:
Transcript:
[00:00]

We've just put a solar PV system in - we've got a Victorian property in Kingston.

[00:08]

It's a bit of a strange sort of construction. We've got an office in a poorly converted roof,

[00:18]

... a pitched roof, that's not properly insulated. We've looked at some projects

[00:24]

that include the costs of improving that insulation, and they're significant. We were

[00:30]

shocked. We were perhaps a little bit behind the curve in terms of what these projects might cost.

[00:36]

So we've had quotes of £30,000 say, and it's taken a long time to get those quotes,

[00:43]

and we just said, "That's madness. We at our dizzy age, we may not benefit from the actual

[00:51]

energy saved." And I said, "Crikey, we've missed a trick here, what we should have done, perhaps,

[00:57]

in here, in benefit of hindsight, we should have put solar in. We should have done that a year

[01:02]

ago." It's taken us a year to work out that we should have put the solar in this time last year.

[01:09]

So we'd like to be a bit greener, but more importantly, because I'm sort of semi-retired now,

[01:17]

the bills in our house are huge, our electric and gas, partly because we're leaking lots of energy

[01:22]

through our roof. We can't easily fix that. So I said, "Let's put solar in, and we can reduce

[01:29]

some of our energy costs and make ourselves a bit greener so we can wear a small..." We haven't fixed

[01:35]

all the problems of the house by putting solar in, but we can improve our robustness, for want of a word.

[01:43]

So you've probably heard most of this, obviously, in the previous talk, and may know already know this, so we chatted to some people, people like Damon who's

[01:55]

got solar, I know one or two other colleagues have got solar, one or two neighbours have got solar

[02:00]

in our street, although we didn't realise they had it, because it just happens there, solar panels are

[02:05]

not visible from the road, but we just happen to know one or two of the people.

[02:13]

We started to chat, we wanted the battery because they're affordable now, I mean,

[02:20]

what I'm talking about today, we've got the VAT has been removed, batteries have reduced in price

[02:27]

because of the... what's the word? The... the... the...

[02:31]

- "The experience curve?" - Well, the... from the electric car business, batteries have plummeted,

[02:38]

it's a bit of an extreme statement, but reduced massively in price. So batteries are now affordable,

[02:44]

whereas they may not have been 12, 10, 15 plus years ago. So it seemed a no-brainer not to have a battery as part of our solar system.  And we've also added as Damon was just talking about, what people call solar diversion, but basically it means that using a smart bit of technology

[03:04]

that works out that you've got energy left and that can be used to heat your water before you may export it.  So we've built one of those into our system too.  All again the things that Mark mentioned, you've got to look at your roofs, tiles, directions, how well you're positioned.

[03:23]

We've got a very large roof, but we've got all sorts of obstacles. In fact, we've got some air

[03:30]

vents and it... when we had a survey, the installer was worried that the existing air vents would be

[03:37]

too high and would found the mounting system. But, you know, we measured that up and, you know,

[03:45]

we got round that. But it would have been annoying if we'd had to put new air vents in the roof

[03:49]

because getting people up on a, you know, quite tall structure, scaffolding and all the cost,

[03:56]

it's expensive. It's best if you've got a roof that's already ready to roll. Batteries need to

[04:01]

be stored ideally outside a property. I can't give you the complete picture, but there is

[04:09]

sort of guidance today that talks about where you place your batteries. They've got to be

[04:14]

the fireproof type, what's the word, provision in your home. It wouldn't be great to put them in a bedroom or hallway or perhaps a loft, they've got to be protected such that in the worst

[04:28]

scenario there was an event with the battery. It wouldn't cause danger to life, so to speak.  We conveniently have a garage, and we've put our battery pack - there's a picture or two coming up -

[04:41]

and we've put our battery in that. All subject to survey. I used the Which?... I'm not a super

[04:50]

advocate of Which?. I'm not overjoyed about some of their assessments of products, but they have

[04:56]

got a trusted trader list of people that would install solar and other trades, and I've actually

[05:04]

used the Which? list. I've put our postcode in, I went through and got the top four or five,

[05:10]

spoke to them all, and got them... I say got them round, got them to do something that

[05:16]

wasn't obvious to us. Typically they won't visit your property unless you're actually going to

[05:22]

make a commitment, because it's quite expensive to do that, to come to everyone's property.

[05:29]

What they do is they do a Google Maps assessment of your roof, they'll quote for the size of system

[05:36]

that you think you want and they guide you towards, and we were lucky that the installer we chose

[05:45]

just happened to be in the area working on another house, and the owners came and had a look at our property as well, but that's not guaranteed from what I can see.  Typically you might have to pay a

[05:54]

deposit for them to actually visit your property, and if they can't install it they refund the

[06:01]

deposit. So that's what we've got in very simplistic terms. We've got 12 panels on the roof.

[06:11]

As Mark previously alluded to, panels have got much larger both physically and their capacity

[06:17]

to generate. We've got panels that generate 440 watts, or can generate 440 watts of peak power

[06:25]

in, you know, in optimal sunlight conditions. We've got another thing that's quite new, we've got what

[06:33]

they call microinverters. So because we've got three disparate strings, we've got three groups

[06:41]

of panels on different faces of our roof. That makes it harder for the traditional inverters.

[06:48]

We've got an inverter in each panel, makes it a bit more expensive, but means that panel A

[06:55]

isn't affected by panel B or panel C. So they're effectively, they're sitting there generating

[07:01]

mains voltages themselves. There's an example of one of the exhibitors' stands, they've got an

[07:08]

Enphase, it is the brand, E-N-phase, but there's other brands I believe, and they've got these

[07:15]

little boxes about so big, and that sits behind the panel. We've got 12 of those, so as an

[07:22]

electronics engineer by training, it sounds a bit crazy, we've got 12 computers on the roof

[07:27]

generating mains, all madness really. We've got a, that green box is a battery and a charger,

[07:34]

there's two actually, it's two physical units, and we've got this energy, Myenergi,

[07:40]

solar diverter, it says power diverter, it should say solar diverter, which actually then feeds

[07:48]

electricity to our existing cylinder, what do you call it, immersion heater, we haven't changed our

[07:55]

cylinder, we've got an existing jacketed 25 year old cylinder, and we're just using the heater

[08:02]

the built-in heater, you can run two heats, so it's probably not optimal what we're doing,

[08:07]

we could probably gain a bit more efficiency by having a modern cylinder with two, with two

[08:13]

heaters, but you know that's more money, it all comes down to money. We've not done this

[08:20]

directly for payback, we're doing this to be as I say, just to be a bit greener, but also to

[08:25]

buffer ourselves.  Once you start generating your own electricity, even for any part of the year, if electricity prices go up ... I don't care, that's somebody else's worry!  We are generating more electricity at the moment than we are able to use, even though I thought

[08:46]

we were quite high-end consumers, but in the night our batteries used to keep the electricity running,

[08:53]

standby, power, so in truth by the morning our battery's empty, we I suppose needed a bigger

[08:59]

battery I suppose, if things were ideal, but a bigger battery, it's across the board, we've got

[09:05]

a battery system, there's lots of different solutions out there for batteries, we've got

[09:10]

one that's expandable, you can add to it, not all are like that, some are fixed, some are not.

[09:17]

How big is it? It's 8.7 kilowatt hours.

[09:22]

Ah, there's a picture, so here's what we've actually got, because we're getting at the end,

[09:31]

we've got eight panels on one roof, we've got three on another pitch, and one just obscured on the

[09:37]

left, just one odd panel on its own, and there's bits of scaffolding there, so the actual,

[09:43]

unfortunately not to scale, but the left picture is the batteries on the floor, there's a,

[09:50]

suppose that's what, five litre bottle of fluid, so you've got some idea of the scale, above it is the

[09:59]

charger, yeah it's the charger mains conditioning unit that does the management of the charge,

[10:08]

and takes the feed from the 12 panels. To the right is a menagerie of bits of electronics and

[10:15]

fused bits.  So on the right hand side up here is our existing smart meter, which we've only recently

[10:21]

had, here's our existing, this was our existing consumer unit, smart meter, inlet to the home,

[10:30]

100 amp, so there's the existing incoming supply with an isolator, this is an additional fuse board,

[10:37]

I say fuse, they're not fuses, they're breakers, but an additional board for isolating the PV

[10:44]

from the main supply. We have a little bit of detail, but we can't see, there's a whole

[10:50]

load of current clamps, little coils, that go around all the various mains wires, and they feed

[10:57]

back to those various bits of equipment in the garage, and tell each of them, allow us,

[11:02]

sorry, to see how much current and energy we're producing. That's it, thank you, I must say I

[11:10]

was really quite impressed, although we had to fix a couple of bits up, we had to do, we had to sort

[11:17]

of, we asked, after they wired it up, we said, my wife said, well I don't like the way you've done

[11:23]

this piece of wiring, could you move it, and they did it, but they did a pretty good job,

[11:28]

I'm pretty impressed, I'm not easily impressed, and they were good, I mean we, yeah, we worked hard,

[11:36]

we had five, six quotes, and yeah, we went through them both in terms of their financial, but what

[11:43]

was more important for us, I think, was the sort of quality of the competency that the company

[11:51]

projected to us, and we may have been lucky in the sense that they visited us as well, and that

[11:56]

probably gave us a warmer feeling, but they just said the right things, whereas others we spoke to

[12:03]

spoke only about panels and things, that's all they were sort of interested in, so these guys

[12:10]

explained how it would work, although they, once it's installed and you've paid, they're, you don't

[12:15]

see them for, you know, for dust, as it were, they're gone, you know, we'll never see them again.

[12:22]

Because I can see there's a gap, there's a gap in learning, because we're completely new, it's

[12:27]

completely new to us, we've got three different apps that, you know, monitor various parts of the

[12:34]

system, and try to get our head round, what should we be doing during the day to maximize the use

[12:40]

of the energy, these are some of the challenges that we're faced with as poor users. And an

[12:48]

interesting thing on that from this workshop I was on yesterday, was we had some study data from 2013,

[12:54]

and it does seem that people do change: they learn how to maximize that, and it doesn't matter where

[13:02]

they're getting a different tariff, I mean people do quite quickly learn how to maximize the benefit

[13:08]

from the amount of solar. We've been generating 26 [kWh] on the very sunny days that we've seen, the very rare few

[13:14]

days we've had, we generated 25-26 kilowatt hours of electricity, which is a huge amount, and

[13:21]

perhaps that's the result of having a modern system, and a system that's now much cheaper,

[13:28]

yeah that bangs for buck, buying it today, the upside of buying it today is it's cheap,

[13:34]

the downside is we've missed 15-20 years, that we where we could have been, you know,

[13:39]

making money and/or saving ourselves money and being green. And what were the absolute costs?

[13:47]

That system that I described that we put on the roof costs [GBP] 12,643 pounds plus a bit of

[13:55]

tidying of roof slates. And that includes the battery? Yeah everything you saw, every single thing that

[14:01]

was in those photographs. Whereas for a similar science system which I started some time ago,

[14:06]

I probably paid three times that, starting in 2008, it made a huge difference. In terms of warranties,

[14:12]

one is nervous, the panels are sort of material technology, although we don't, the brand is a

[14:21]

brand. So these panels are all Chinese today, whether we like it or not, as far as I know.

[14:27]

Japanese were sort of major players and inventors and innovators, but Japanese panels would be

[14:32]

extremely expensive now, against the Chinese. The battery packs have got, the battery pack and

[14:38]

inverter technology, sorry the battery pack and charger that we've got, by company called Fox ESS,

[14:46]

that's got a 10 year warranty. The panels have got a 25 year warranty, the microinverters that

[14:52]

are in the panels have got a 25 year warranty, the solar diverter has got a three year warranty.

[15:00]

And I thought it was good value.

[15:02]

It's about a thousand pounds per sort of, you know,

[15:06]

panel's worth, if you like, as a rule of thumb.

[15:10]

You can add to that battery pack.

[15:11]

As I mentioned, you can take another slice and add it on.

[15:15]

Maybe we might need to do that

[15:18]

if we can justify that additional cost.

[15:21]

Because if we export that,

[15:23]

we're going to get with our existing providers,

[15:26]

I can see almost nothing for the exported energy.

[15:30]

Maybe we can move to a better energy provider,

[15:33]

or maybe we can find a way of using more electricity

[15:37]

by putting air conditioning in, which I'm thinking of today.

[15:40]

- But what is worth getting on this workshop

[15:42]

as the Centrica representative was claiming

[15:43]

they thought their export rates were good.

[15:46]

You see, you can switch retailer to...

[15:48]

- Sure, sure.

[15:49]

I took a view,

[15:52]

the sort of the engineer bit in me says,

[15:56]

don't change everything at once.

[15:57]

We've only had this solar working about a week.

[16:00]

We had some snagging.

[16:02]

We had a current, one of those plants didn't work,

[16:05]

and that caused a bit of disruption in the install.

[16:08]

So that install that was supposed to happen over two days

[16:11]

was delayed by another week and a half

[16:13]

while they got spares, by the time

[16:15]

they could get an electrician back to change that.

[16:17]

So the install was not quite as seamless as was planned,

[16:21]

but that's sort of life, I suppose.

[16:23]

We've also had all those components, I say all,

[16:27]

they all communicate wirelessly or cable

[16:31]

to your existing Internet router

[16:35]

provision in your home.

[16:37]

And we've got most of our equipment out in the garage.

[16:41]

Our WiFi is not brilliant in our house.

[16:43]

Our house, like many Victorian houses,

[16:46]

is quite challenging, WiFi-wise.

[16:49]

And although they installed it and said "it's all fine,"

[16:52]

of course, two days later,

[16:54]

one of the units stopped communicating and we lost contact.

[16:59]

It doesn't stop the solar generation.

[17:02]

So you're not going to lose energy or provision.

[17:06]

You can't see it on your phone or computer.

[17:09]

So I've actually had to fix that myself, that bit.

[17:12]

But that is your problem.

[17:14]

That is not the installers'.

[17:16]

They're installing solar.

[17:18]

They're not coming to sort your IT networking

[17:22]

infrastructure out.

[17:24]

They can only do their best on the day.

[17:27]

- I think this is an important point.

[17:28]

A well-designed system.

[17:29]

You might lose the ability to see what's going on,

[17:32]

but it should all completely continue to work.

[17:35]

My view with my own is,

[17:36]

if I get run down by a bus tomorrow,

[17:38]

the rest of my family shouldn't have to do anything clever.

[17:41]

It should just continue to work

[17:42]

and we can change WiFi rather than whatever.

[17:44]

So you should always build your system

[17:46]

so that at worst, if your Internet goes down,

[17:49]

it just does something sensible and continues to work.

[17:53]

And yours is like that.

[17:54]

So that's how you should build.

[17:55]

- We've not touched anything.

[17:59]

One piece of feedback I've given them,

[18:01]

they asked me for feedback and I've given it to them.

[18:04]

- Oh dear!

[18:05]

- Yes, exactly.

[18:07]

And they're still recovering.

[18:08]

They don't seem to give what I would call a handbook.

[18:12]

You get all the manuals from all the different

[18:15]

appliances, but there's no overarching

[18:19]

from this install.

[18:21]

And I would put money on it.

[18:23]

It might be most installers I would hazard a guess.

[18:27]

You don't get a user guide that tells you what you've got

[18:32]

in your system and what Damon's point about,

[18:36]

what, how do you change, if something broke

[18:39]

or you had to replace item A,

[18:41]

what are the implications on the rest of the system

[18:44]

or what settings do you have to replicate?

[18:47]

There's no, there's nothing.

[18:49]

It's just left working and that's, it's up to you,

[18:52]

over to you.

[18:53]

I think there's a gap there.

[18:55]

The gap for a third party service, I don't know.

[19:00]

- Or you could just pay, it would be worth having

[19:01]

a premium install service where one of the things they do

[19:04]

is such a guidebook and secondly is some guaranteed

[19:08]

support time on the end of a phone.

[19:09]

- Yeah.

[19:10]

- That would well be well worth many people paying.

[19:12]

- Yeah, I get why there isn't that,

[19:15]

but I don't think that's good enough.

[19:18]

But because they're accountable,

[19:21]

they're going to pay more.

[19:23]

And this business, like all these things,

[19:25]

it's very, you can see it, you can see it.

[19:27]

All the quotes we had by one and two were all pretty tightly ...,

[19:31]

they were all very similar.

[19:33]

It was actually quite hard to work out one from another.

[19:36]

So I can't give you too many numbers

[19:40]

because I don't know them all myself.

[19:42]

I think we've done well with a good value system,

[19:46]

but only time will tell.

[19:48]

Ask me the same in six months time or something.

[19:51]

Yes, sir.

[19:52]

- Any issues about planning?

[19:53]

- Any--

[19:54]

- Issues about planning?

[19:56]

- Well, as I understand, two things have to take place.

[20:00]

You have to use, we've used, well, I don't know about have to,

[20:03]

but we've used an MCS,

[20:04]

what's the word, approved installer.

[20:09]

They have to validate that,

[20:12]

and they seem to take responsibility

[20:15]

for that planning question as I would understand.

[20:19]

We've not had--

[20:20]

- I'm going to argue with you here, Alan.

[20:21]

So I'm the general--

[20:23]

- Sorry, let me finish.

[20:24]

We've not had to, we've not applied for any planning.

[20:26]

- No, sure.

[20:27]

- And I don't believe that's required in our area.

[20:30]

- General Permitted Development Orders

[20:32]

for England and Wales, anyway England,

[20:36]

say that providing you stick to certain rules, restrictions,

[20:39]

you do not need permission for so.

[20:42]

Now, where you do get restrictions

[20:44]

are if you're in an Area of Outstanding Natural Beauty [AONB],

[20:46]

you're in a heritage site, listed building,

[20:48]

there are a few restrictions,

[20:49]

and 10% of Kingston buildings are in conservation areas.

[20:54]

So there are a few restrictions,

[20:57]

but the rest of the 90% of us,

[20:58]

unless you do something absolutely ludicrous,

[21:01]

you don't need planning.

[21:02]

Now, ... go on.

[21:03]

So, and the other thing, one thing that the provider,

[21:07]

the installer has to do is get permission

[21:12]

to your home to attach your solar panel network

[21:17]

to the grid, and that's getting DNO [Distribution Network Operator].

[21:21]

So there is a bit of sort of implicit permission-getting.

[21:24]

- But again, if you stay, but there was a certain limit,

[21:27]

you just tell them afterwards,

[21:29]

but you have to tell them.

[21:30]

- Yeah, five kilowatts peak, I believe,

[21:32]

is the-- - 16, sorry,

[21:35]

16 amps per phase, which is 3.78 kilowatts.

[21:38]

- Okay, but no, we've got the maximum, I believe,

[21:42]

five kilowatt peak is the maximum normal permitted connection.

[21:47]

- Normally 16 amps per phase,

[21:50]

you may have no advantage,

[21:51]

but we always get permission for more.

[21:52]

- Okay, well, we've got it.

[21:54]

So I don't know if that's answered it,

[21:56]

but we've done nothing.

[21:58]

Yes.

[22:00]

- Thank you.

That's really interesting to hear your experience

[22:02]

in installing co-located battery with solar.

[22:06]

I agree, I suspect that it is probably not in their interests

[22:08]

to share too much by way of a

[22:09]

manual at the end of it,

[22:10]

because they don't necessarily want you to be experts

[22:13]

in the system after having installed it.

[22:15]

But I was interested in your experiences

[22:17]

of that part of it in terms of how you've managed to,

[22:20]

you said you think you mentioned you mentioned

[22:22]

you get an app to sort of--

[22:23]

- Well, we've got, you get an app,

[22:25]

there's an app for the microinverters

[22:29]

that have got their own online app / cloud,

[22:34]

which stores the data,

[22:36]

how much energy you're producing,

[22:38]

how well each individual panel,

[22:40]

let the remotely access those,

[22:43]

they being Enphase,

[22:45]

can remotely access them and sort of install the level

[22:48]

that you've got, you and I can't access.

[22:50]

But we can see, look at that app

[22:53]

and just see how much energy each panel's producing

[22:56]

at any time during the day and export.

[22:58]

You can export spreadsheets or not spreadsheets,

[23:01]

but you can export the historical data.

[23:04]

We've barely got enough,

[23:06]

so we're worrying about that at the moment.

[23:08]

And then there's an app for the battery pack

[23:11]

and there's an app for the solar diverter.

[23:14]

And but they're three different,

[23:15]

because we've got three different companies,

[23:18]

three different manufacturers of equipment,

[23:20]

there are three different apps,

[23:22]

there's no single overarching ...

[23:24]

- So for example,

[23:26]

if he got his batteries from Libbi,

[23:28]

which is also from Myenergi,

[23:30]

then as it happens,

[23:31]

by coincidence then the batteries and the diverter

[23:34]

would share an app.

[23:35]

So there are choices you can make

[23:37]

if you want to make it.

[23:38]

- But we've got one at the battery app,

[23:40]

just to answer your question,

[23:42]

to be slightly less unfair.

[23:44]

The battery app actually shows you pretty much everything.

[23:47]

It shows you the amount of energy you're generating.

[23:50]

It shows you the status of the battery,

[23:53]

and it shows you the amount of energy you're exporting.

[23:57]

So if you just look at that one app,

[23:59]

you get an overview of what's going on.

[24:02]

So it's--

[24:03]

- And you can get that information to be able to tell

[24:06]

whether something's not working within that system,

[24:08]

like one of the panels is not working.

[24:10]

- Yeah, well, the battery's starting to--

[24:12]

- Pictorially, if you look at the,

[24:15]

we look at our Enphase, the microinverter,

[24:20]

I could have put some pictures of that in.

[24:23]

I've got pictures, but not here, ...

[24:26]

Yeah, you see each individual panel.

[24:29]

You can actually set up, I discovered,

[24:33]

yeah, I said it lost its WiFi.

[24:36]

The irony is, I discovered afterwards,

[24:39]

you can get it to send alerts if there's a fault.

[24:42]

But unfortunately, because the fault was

[24:46]

that the WiFi broke, it obviously wouldn't be able

[24:50]

to send an alert, so that's a bit of a--

[24:52]

- Oh, there's loads of hundreds of status LEDs

[24:55]

that we've struggled a bit to try and work out.

[24:57]

But you don't need to know, you don't need to know, really.

Show Notes

Recorded with the Zoom H1n, stereo 48ksps, sitting on the desk at the front of the drama room near the speaker.

~4503 words.