PV slate solar slate tile: does anyone know about these?

[Bit-overwhelmed]

I think I am going to need a new roof in the next couple of years. Nail rot causing slipping slates, one sinking area in part of roof.It’s a big house 5 bedrooms , south facing . Not listed and not in National Park.
Currently Welsh slate, no felting underneath. Has been there for as long as living memory. Occasionally find old stone slates in the garden so presumably originally roofed in those. Timbers inside attic look very woodwormy but after lurking here for a while I am not too worried about that. I had an upgrade to my loft insulation , courtesy of a Welsh government scheme.
I get slipped slates repaired regularly, gutters cleaned every year.
Very rural, oil fired aga, electric storage heaters, no mains gas, two wood burning stoves.
I have never gone for solar panels on my roof because a) I think they would look hideou and b) I don’t think the roof was designed for them so I was worried re structural implications.

Somehow I found a site called www.gb-sol.co.uk
Established in 1999 aas a spin out from Cardiff universit, they make, amongst other things, PV slates which look like slates but are made of toughened glass and aluminium .
Apparently they’ve been on Grand Designs and have also been used on the refectory in York Minster.

They need a border of natural or infill slates, obviously looks better if their matching infill slates are used.
Electrics and commissioning pack are extra.
There is a 25 year guarantee, which doesn’t sound very long to me! But I am 64 so they would hopefully see me out (?)

Does anyone have any knowledge or experience of this system, please?
Would I be safer sticking to the traditional Welsh slate roof?
Many thanks in advance for your wisdom.

 

[a twig]

How much money you got?

I haven’t installed the particular system but I did work in the R&D of photovoltaics for a while back when all this was being developed, so can speak generically

The tiles will start failing (as in stop generating electricity) after 10 years or so as the thin films break down, I’d expect >90% to be dead after 20 years. Efficiency also worsens through their lifetime, so your setup will be generating significantly less after year 10 compared to year 1. Orientation of your roof also plays a part in how much generation the system will provide in reality.

To get enough energy for a 5 bed house you’d be looking at minimum 5kW install which would probably be upwards of £17-£18k.

The whole roof existing roof has to come off, you will need additional wiring done (which dependent on the state of your current electrics may prompt further upgrade work) and you may need to uprate timbers. It may also prompt a new heating system as given the reduction in feed in tariffs, excess generation is often used to electrically heat a hot water tank for e.g to give you “free” hot water rather than “sold” back to the grid.

It would definitely worth getting specific quotes for both (including all the ancillary work) so you have proper like for like comparisons, you could then do a quick payback calculation to see if the reduction in your energy bills would pay for the additional cost vs a slate roof.

Two years ago given your age and location in “sunny Wales” I’d have said definitely don’t bother, but with energy prices now being where they are, the reduction in competition in the utilities market and the proposed phasing out of heating oil that may no longer be the case.

Please do keep this updated, would be really interested to see how the numbers work out.

 

[Bit-overwhelmed]

How much money you got?

I haven’t installed the particular system but I did work in the R&D of photovoltaics for a while back when all this was being developed, so can speak generically

The tiles will start failing (as in stop generating electricity) after 10 years or so as the thin films break down, I’d expect >90% to be dead after 20 years. Efficiency also worsens through their lifetime, so your setup will be generating significantly less after year 10 compared to year 1. Orientation of your roof also plays a part in how much generation the system will provide in reality.

To get enough energy for a 5 bed house you’d be looking at minimum 5kW install which would probably be upwards of £17-£18k.

The whole roof existing roof has to come off, you will need additional wiring done (which dependent on the state of your current electrics may prompt further upgrade work) and you may need to uprate timbers. It may also prompt a new heating system as given the reduction in feed in tariffs, excess generation is often used to electrically heat a hot water tank for e.g to give you “free” hot water rather than “sold” back to the grid.

It would definitely worth getting specific quotes for both (including all the ancillary work) so you have proper like for like comparisons, you could then do a quick payback calculation to see if the reduction in your energy bills would pay for the additional cost vs a slate roof.

Two years ago given your age and location in “sunny Wales” I’d have said definitely don’t bother, but with energy prices now being where they are, the reduction in competition in the utilities market and the proposed phasing out of heating oil that may no longer be the case.

Please do keep this updated, would be really interested to see how the numbers work out.

Oh my goodness 10 years is a disappointing time to start failing.
I have lots of trees for my log burner which I am expecting to last a lot longer than me!

 

[a twig]

There will be very few failures at 10 years - I might not have made that clear above, I was trying to say that that would typically be when you start to see the first failures, but after that the failure rate will increase, it’s not linear sadly.

 

[GB-Sol]

GB-Sol here - our PV Slates are made of toughened glass, aluminium and highly efficient crystalline silicon, so come with a comprehensive 25 year warranty. We do not use the thin film technology mentioned above. PV Slates are mechanically fixed to the roof and interlock with each other, so there is no risk of then falling out over time. Details and pricing all on our website.

 

[a twig]

Thanks for popping in and sharing your views.

Your own warranty says that power output will be 90% after 10 years and 80% after 25 - so the point where failures start is broadly in line what I was saying, and as much as I wish you every success, the 25 year 80% is unlikely to ever be claimed against as chances are the original purchaser will have moved on or the company will be no longer trading.

I did take a look at your site, very little information that I could find on the manufacturing process and construction of the tiles. There were also no easily accessible test reports to back your numbers. I’m interested to hear that your panels don’t have a TiO2 or SiO2 coating, they are usually critical in reducing the reflectivity and thus improving performance - so you must be sacrificing significant performance if you are just sticking the crystalline silicon behind glass?

Just to make it clear I’ve no axe to grind on this, I’m a big supporter of UK innovation and manufacturing and it would be great for Welsh industry to be revived in the new Green economy. I’d be quite happy to accept that things have improved over the last few years, just not currently seeing any evidence.

 

[GB-Sol]

Hi there,

The performance warranty of 90% after 10 years is industry standard for crystalline solar panels. It refers to the reduction in output that each panel faces over time. We would not expect any units to fail during the 25 year warranty period.

We don’t publish our manufacturing details or test reports, and that is the norm for most PV manufacturers. However, PV Slate is MCS certified, which is your assurance that the product has undergone extensive independent testing and that our factory is audited every year.

Your point about solar companies no longer trading is a really interesting one. Most seem to live for 5-10 years. GB-Sol did the UK’s first edge to edge solar roof 28 years ago, which is still working well.

For more technical details on PV Slate, please check out the brochure available on the GB-Sol website. And thank you for your support of Welsh manufacturing!

 

[dbradp]

Are GB-Sol products distributed in the USA yet?

 

[Toby Newell]

I am as big a sceptic as twig but I think the best designed PV's have advanced a lot in recent years but like LED's (which are basically PV's in reverse) their efficacy degrades over time and there isn't anything you can do to stop this, just slow the process down. I feel bad for PV companies that have invested a lot in R&D and capacity, the government seems to introduce incentive schemes then randomly cut them back or scrap them. This encourages unscrupulous actors to jump on the bandwagon giving everyone a bad name and the uncertainty hurts the good guys who are in for the long haul.

There should be a long term comprehensive suite of tax breaks and an effort to concentrate on home to grid integration for PVs and EVs as that is the only way we will be able to fulfill capacity in the coming years. As per usuall when we start getting brown outs in a few years time as the national buffer drops polititians will finally wake up.

 

[Flyfisher]

PV systems are already VAT-free, which includes an EV charger if installed at the same time.

However, the cynic in me suggests that tax breaks and subsidies can have unintended consequences, such as increasing the installations costs, which I think happened with the government schemes to subsidise loft insulation by 50% but only if installed by approved companies. Good scheme for the installers though

 

[Toby Newell]

PV systems are already VAT-free, which includes an EV charger if installed at the same time.

However, the cynic in me suggests that tax breaks and subsidies can have unintended consequences, such as increasing the installations costs, which I think happened with the government schemes to subsidise loft insulation by 50% but only if installed by approved companies. Good scheme for the installers though

My point exactly. Long term approach needed not kneejerk short term schemes where niave installers jump on the bandwagon and hoover up all the funds.