odysseus2000 wrote:I may be completely wrong on roof top solar, so happy to be corrected. My thinking goes along these lines.
The advantage of converting ones roof to solar are financially significant, a neighbour had a return of purchase price in 5 years with a 20 year contract & if electric cars become common I expect solar & storage to become standard additions to most of the uk building stock. Aldi supermarkets clad all the stores I have seen with solar but so far not many others do, but I expect that to change
In terms of other electrical goods, a 30 year life time is a lot more than one expects for say a fridge, boiler...One of the houses near where my business partner lives has just had a new roof after initial build in the 1960's, costing a few grand & done in around a day. Other folk tell me that tile roofs like this have a finite lifetime measured in several decades whereas Welsh slate has life times of multi centuries for the slates, but they too suffer from the sagging or rot of battens etc and need maintenance every few decades.
Last week I was traveling by lots of new build, over half had roof top solar, most of the bolt on type that is very common all over the country, but with maybe 15% having the solar panels sunk into the roof so as to be level with the existing roof. These roofs do not look as pretty as a tile or slate roof & presumably have trouble in conservation areas.
The bolt on panels seem to be remarkably robust. I have never seen one blown off and are presumably relatively cheap to replace. So the case for solar tiles would be aesthetics & being able to get more capacity with out the constraints of bolt on solar panel size and then one would have to focus on the cost & reliability.
From my ignorant stand point it would seem that one system of roof & power would be better than two systems of roof & solar & a 30 year life time would be similar to the 30 year insurance backed warranties offered on new homes.
So why is tile solar not liked? Is it the difficulty of connecting the tiles or some other aspect that I have failed to identify?
Regards,
Ody,
Your post contains quite a lot of ignorance. So much so that it is difficult to know where to start. I'll try ....
Concrete roof tiles have a lifetime of the order of a century. Slate was on my roof for about a century and I am seeing no degradation in my concrete after 20-years and am fully expecting another 80-years out of them. Really the limiting factor for both is the underpinnings. In contrast PV modules are likely to have lifetimes of the order of 25-years or so, mostly driven by module edge delamination or storm damage. So it makes no sense to put a roof on that needs mostly replacing every 25-years. Better to split the two functions, which is what the normal PV module above a roof does. Then consider the replaceability of a single module (is the right size still available) in the event of damage versus that of a roof tile. If you function share the roof tile to become a solar tile then you multiply these replace & repair problems a thousand fold.
The next issue is that solar modules behave best when cold. Putting their back side into a hot roof space is a real no-no. The only reason it is done is because the NIMBY brigade anti CC brigade and anti renewables brigade use aesthetics as a way of blocking any solar PV in their area. The work around is to set the PV flush with the roof, which in practice means it has to become the weather proofing of a roof. So the heating loss is accepted as the alternative is nothing. This in turn causes all sorts of fire risk issues which have caused endless grief to people like me who write & sign off the standards, because there is a burn-through time spec that the roofing system has to meet so as to alllow time for a fire brigade to clear a building before the roof turns into a chimney. If in any doubt of how hot a potato this can be go and look at Grenfell. Oh and did I mention that the weather proofing itself can be an issue.
Then you get to the connections problem. The best connection is the one that isn't there. This is a manufacturing cost issue, a installation cost issue, and a reliability & safety issue. So the largest possible module creates the fewest possible connections per roof. In contrast a solar tile roof probably creates about a hundred times a many connections as a PV module system.
Then you get the installability issues. I don't know about you, but when I put tiles on roofs I put an angle grinder through quite a lot of them. Try doing that with your expensive delaminating solar tile. Or are you going to have a mixed roof. Did I mention that they are different trades on a roof by the way.
Then I get to the performance issue. You want the minimum edges (loss) to the maximum producing space. So the big module wins hands down over the small tile every time.
The only other reason that the building integrated PV systems (BIPV) exist is because the manufacturers conned the politicians into giving them an uplift in the tariff in a number of jurisdictions. That was partly because they wanted compensating for the INCREASED COST of installing a BIPV system, and partly because they wanted to push their consumers into buying these systems. It was the French wotdid it because there was a few (mostly) French factories that were making this stuff back in the day. I used to distribute this (for a non-building application) at the time and so got quite aware of the behind-the-scenes manoeuvring that was going on. I am afraid the £$$%^&-fest continues, although it does change shape a bit.
I'm sure there were other reasons, but this is enough. Really this aspect of the Tesla business should have a stake put through it.
regards, dspp