I think a major challenge that is yet to be addressed is the fact that solar panels lose their efficiency over time [1] [2]. Seems like you're looking at 80% of rated efficiency after 20 years - and I'm unsure this includes failures.
In the UK a 50+ year old roof is very common - most people expect a house to outlast them without anything but minor repairs. If I were building a house I would want something where it's primary power source can be repaired without larger than necessary costs.
UK roofs are made and ceramic and slate. US roofs are made of asphalt. Mostly because asphalt is inexpensive (particularly due to economies of scale/lack of them on ceramic). Ceramic lasts a lifetime, asphalt can be taken out by one bad hail storm.
UK homes are made of brick. US homes are made of fiberboard and inexpensive woods. There's a reason why UK homes have lasted over one hundred years, and most US homes won't last 50. It is a consumer culture applied to homes. They're designed to be replaced completely.
Very much depends on how it is constructed. As a Swede 100% used to sturdy, well insulated wooden homes having lived in Texas for a while it felt like they were made of paper in comparison.
Then Sweden is also known for ridiculously high building standards, even compared to other European countries.
New builds have lower life expectancies. Thing about your fridge from the 40s, compressor built to last. How long has your stuff been lasting recently?
A tip someone told me here in the UK is that if you are buying an inexpensive property try and get one that was built and owned by social housing operators - they actually have much higher construction standards and will have been maintained properly.
I've lived in 11 properties in the UK (owning 4 of them) and most of them were made of stone and were 150+ years old - only the first one (a 1950s council house) was brick.
Well, it would have been a huge waste to build houses to that standard here because they all would have had lead paint! Nobody knew that then, but still. I recently considered buying an old house and ended up with a post-1978 one so I don't have to worry about that.
Also, people mention again and again that people replace houses in Japan even more, and yet it doesn't seem to get the jingoistic juices flowing like criticizing the US.
Of course, since Tesla's cost comparison only works out if you compare their solar roof to one of those more expensive ceramic/slate roofs, it seems fair to compare the lifespan to those roofs too.
50 years is almost new. Most 100 year old terracotta tile are still on the original set, and slate often lasts 200.
Where roofs are replaced, aside from storm damage, it's most common for that to be down to having got rot in the woodwork than fault with the tile. I suspect a fair few are down to iffy sales tactics from dodgy builders. (i.e. get someone out to fix the chimney flashing "oh, major problem you need a whole new roof...")
A relatively routine roof replacement required because it is now expected to serve more than one purpose (simultaneous weather
- proofed shelter and PV surface area) could be justified, especially if the entire neighborhood utilizes its existing local grid because the entire street of individually owned Powerwalls is one large shared, connected, metered (people with high energy needs could still run welders and power tools that pull from other Powerwalls), software driven reservoir:
Each existing home (even ones built in newly minted neighborhoods) would still be connected in parallel. It's the nearby 70-150kV subtransmission relay station historically feeding that parallel bank of homes that would become inactive - ironically bypassing the Nikola Tesla prompted long distance HV amperage flow from remote generation sources. AC implies spinning dynamos (loud flywheel momentum), and PV-to-battery is solid state, with high frequency silicon carbide switching (quiet). Classical home 13kV transformer bypassed or replaced with a small DC boost to launch amperage across the hundreds of feet of a neighborhood's acreage. Typical loads could be balanced even if a few people want to weld or smelt metals during a bright sunny day (especially summer solstice).
As a comment above pointed out, the solar capacity would decay over time, but since there is a local grid reservoir buffer - the reduced capacity PV over time can mean the high quality glass protection can be kept even when cells under them are down below 50%. Such a roof would be contributing less to the reservoir than neighbors feeding the same grid with newer solar roof replacement. The user can be paid for their generation if they use less than they produce, incentivizing low noise, subtle generation sources (charging your powerwall with an exercise bike like Jaimie Mantzel, adding your electric vehicle(s) charge reservoir to the neighborhood grid if next day commute will mean you're parked near other solar roofs that will top you off until ready to return home - transporting and trading energy).
50 years? I have noticed that slate roofs are much more common in the UK than the US but still I see majority asphalt shingles, curious what y'all call them, on single family homes built within the last couple hundred years.
I wish y'all had some more thatch roofs but I suppose given the history in London, driving to the Cottswolds to see a thatched roof is probably fine ;)
In my local area we did, but at one point there was a push to demolish them all as they were "unsafe". I have a few stories about this for another time...
The problems with thatch is it's relatively hands on, you have to swap it out occasionally as the stuff rots.
The manufacturer states 25-30 years for shingles, but it's rarely the case they actually last that long unless you're paying for premium shingles. I'm in Canada though, so perhaps the harsher weather has something to do with that. Regardless, in Canada at least, 25-30 years for shingles is not common; 15-20 is more realistic from what I can tell in my area.
GAF has a 50 year warranty on its shingles. People who are talking about failures after 10-20 years are buying cut rate product and having it installed shabbily.
Why do they degrade so quickly? I also live in UK and replacing an entire roof is not a common thing to do, every 50 years sounds about right, my roof is 35 years old without any leaks.
UK roofs typically aren't asphalt shingles like most homes in the US and Canada. Asphalt shingles are closer to sand paper than the tiles you're accustom too.
We had to replace ours after only 15 years (and we should have done so earlier). The manufacturer's claims are suspect. Expansion/contraction due to the hot/cold cycle caused ours to crack (literally apart in some cases).
> Seems like you're looking at 80% of rated efficiency after 20 years
If you are living off grid, that might be an issue although it could be fixed by just getting some more solar panels later or oversupplying at first. However, for people still connected to the grid, they can just use a little more later on from the grid so I don't see what the big deal is.
In the UK a 50+ year old roof is very common - most people expect a house to outlast them without anything but minor repairs. If I were building a house I would want something where it's primary power source can be repaired without larger than necessary costs.
[1] https://energyinformative.org/lifespan-solar-panels/
[2] https://www.engineering.com/DesignerEdge/DesignerEdgeArticle...