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Solar power roof
- Thread starter MOE J
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- solar roof for tesla
See post #30 for the range of EV PV conditions and output.
It's obvious that if we could wave a magic wand, and suddenly have every PHEV/EV be equipped with PV solar panels, that it would reduce the amount of power that the grid would have to supply for EV charging. There's also the attendant problems of increasing grid capacity and extending the grid to charge every EV/PHEV in existence, when millions of EVs parked outside during the day could charge, in whole or in part, with no need for a grid connection.
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I personally would rather have an M3 with no glass roof at all, because it's not really a rational benefit to me and having to replace one, even without PV elements, is going to be costly. At least with PV the glass roof would be reducing my running costs, rather than increasing them as per the existing glass roof's tendency to warm (in summer)/cool (in winter) the car inappropriately.
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It would probably be cheaper yet to use the existing grid and mandate that we all walk, bike or take transit to get around, but that's not likely to happen.
There's two separate issues here;
1) the ability of an EV/PHEV to generate PV solar, which is a proven fact, and then the marginal cost of mass implementation via mass production of EV/PHEV vehicles fitted for PV. The power generated is directly stored in the vehicle's HV battery.
2) the cost of increasing grid capacity and extending it to provide the needed charging power for mass adoption EV charging. Increasing grid capacity is somewhat amenable to mass production but still requires lots of labour to actually install it (along with the needed battery storage to buffer the grid), via mass solar farms or via rooftop or similar installs. Adding charging posts is and probably always will be, for the foreseeable future, a labour intensive activity.
So we can see that 1) is an exercise in largely robotic mass production, and 2) is an exercise in largely labour intensive production.
1) will be cheaper, by far.
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Wouldn't the solar panel be underneath the tempered glass so it would essentially have similar durability? If the solar panel electronics themselves break - why do you have to replace it? If it's not worth it just leave it broken.
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Electric cars have been around for a long time, so no one said "count me out" about the technical viability of an electric car. The issues were about mass production, not Technical.
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ucmndd
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The main limitations for automotive applications are surface area and durability.
Surface area being the big one. Commercial solar has been around for more than 50 years. Since the 70s, average efficiency of PV cells has risen more or less linearly from ~10% to about 20%. Even if we had 100% efficient solar panels, which we never will, a square meter of surface area would still only produce about 1400 watts in perfectly ideal conditions.
Even half that is currently a pipe dream at anything approaching a reasonable cost.
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Your point two is utter crap(sorry to burst your bubble!). There is TONS of extra grid capacity right now. The grid and its generation plants are built for worst case hottest or coldest day scenarios. You can easily tell EV owners they can only charge at off-peak times, either via edict or vie monetary encouragement.
The other problem is that even with the very most efficient(now or theoretically possible) cells covering the roof/hood/trunk of the car they won't put a meaningful dent in MOST car's electricity usage. They'll still go home and plug in. That, and many EV's don't live in Arizona or Israel(just two examples). Many live in Norway, or Canada, or New England, where their PV cells will do even less, like maybe 1/3 of the best case, a true waste of money, space, and resources.
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NOT!
The plan is to phase out all fossil fuel electrical generation and replace it with renewables, so there will be a need for a massive expansion of PV power and associated costs. And the plan is for ~100 million EVs on the road and the costs needed to provide charging for them.
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Sure, but here’s something to consider for now.
Aptera has solar charging for their car. They claim charging “up to” 40 miles per days. And if I recall correctly, they also claim about 10 miles per kWh. They are based in “oh-so-sunny” San Diego (I lived there for a bit). So, in some rather “realistically ideal” conditions you can get about 4 kWh per day. So for the more southern states, that might work.
But for the more northern states, expect less range from solar.
With a 10 mile per kWh estimate, that means it’s something like 2.5-3x more efficient than a Model 3. That means, in similar weather, the M3 might get “up to” 16 miles of range per day. And again, less in more northern states. And that assumes it has the same coverage of “panels” on the car, which we know it can’t.
The solar panels Aptera uses are all highly opaque, meaning it can’t be used everywhere. So, if we “sacrifice” the roof and make that solar, that means you only have the roof and front hood. Aptera has the rear covered, but it’s not used for driving visibility. I’d say between the roof and front hood of the M3, that’s maybe 2/3 to 3/4 at best of the Aptera”s total coverage. So, of that precious 16 miles, you’re now down to about 12 miles, probably less.
Is that worth the extra cost in materials? Weight? Time for manufacturing? Does “You can drive 10 miles on solar” sound all that good to the average buyer?
Consider that the adoption rate of EVs is in the 10% range of all cars and who knows what percentage of that would be willing to pay extra for a solar charging option on a car. Well, we have Aptera as a “litmus test.” How’s their adoption rate?
If the manufacturing is excellent, the more likely reason to replace the glass plus PV elements would be damaged to the glass itself. And since those element have to be manufactured as part of the glass before they’re installed onto a car, it automatically raises costs any and all that deal with it.
The problem is, no matter what the grid has to grow. Every new car, house and all the appliances that go with them, not to mention industries. The grid has to grow. The offset from solar charging a car would fall into “margin of error” for such expansion.
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Sure… but question for you. That article came out a year an half ago… the company did deliver a few cars, but then halted production a mere month later. Their car was expected to cost 110k euros, but ended up in the 250k range.
Supposedly working on a LY2 car… anything since?
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The cost to produce a low volume EV (or any Hwy capable vehicle) is always going to be exorbitant.
This is the pertinent part of the article:
"The Lightyear 0 is said to offer a WLTP range of 625 kilometers (388 miles), with the 5 square meters of double-curved solar panels said to provide an additional 70 kilometers (44 miles) of range per day in ideal conditions.
In cloudy climates, Lightyear reckons the solar panels will produce enough electricity to cover 35 kilometers (22 miles) a day. The Lightyear 0 is a highly efficient car, with an energy use of only 10.5 kWh per 100 kilometers (169 Wh per mile)—thanks in part to its record-breaking coefficient of drag of only 0.175."
44 x 169wh = 7.4kwh
22 x 169 = 3.7 kwh
or an average of ~5.5kwh/day or about 27 miles of range for my M3, which is about 90% of the range needed for the average commute in North America.
Multiplying the above by ~100 million = 550 million kWH.
The LY 0 has about the same dimensions as an M3.
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"Said to provide" is a buzzword for "never gonna happen". "Reckons"? That sounds like they probably know it won't, but don't want to tell you.
Literally 30 seconds of web searching gets me this "On a cloudy day, a solar panel can typically produce 10 to 25% of its typical power capacity. " and "Solar panels can produce electricity on cloudy days, but not always on overcast days. " and this is from a company that does its business designing solar arrays(Solar Alliance | Commercial & Residential Solar Company). I assume they are not exaggerating because they don't want to get sued. I know you REALLY want Lightyear to be not lying and your REALLY want car solar to be worthwhile, but IMHO neither is true. Its cool though. Sign up for your LV0 or LV2 for 250k, and let us know how it goes.
Once again, don't forget that many of us(people who live on earth in population centers) do NOT live in ideal conditions. Between the latitude and clouds, It looks like New Englanders might se a bit more than half of that. Note you could say the same about Norway, Ireland, England....
I see you are in southern BC. Average Peak Sun Hours by Province in Canada - Solar BC says 1200-1600 peak sun hours per year, which turns into 3.28-4.38 per day. You know what 'Ideal' probably is.... Arizona, at 7-8 peak sun hours per day. So the ABSOLUTE BEST CASE you MIGHT get half the purported 7.4. And that's assuming when you park your car at work its in the middle of an open parking lot with no trees/buildings around, not the convenient spaces where it'll be in full shade for half the day.
And just for confirmation... 5 sq meters is ~54 square feet. Multiply that by 21.2w per sq foot of panel, and we get 1145 watts, in full sun. Stick that in Arizona perfectly inclined to the sun, and you get 8kwh. At least they are not obviously lying about that number(yay!) I assume the difference between 7.4 and 8 is they are either rounding up to 5 sq meters or they simply can't get all the cells to point in the same (ideal) direction at once.
Don't forget that these 100 million cars are going to be lugging around an extra ~75lbs of solar panels. (It'd be 128, but I'm assuming there's a 50lb savings for building them into the roof. That's going to be wasted energy for every mile driven.
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Don’t forget to deduct 20% because they use WLTP, compared to EPA (generally regarded as to be more than 20% higher than EPA). So your 90% drops to 70% (~21 miles). Less in reality since even EPA is overly optimistic at times.
And what is the 100 million supposed to represent? Half a billion kWh sounds nice, but again, what is it supposed to represent? There are maybe 2.5 million M3s out there right now (rough guessing based on last four years of M3 & MY produced when googled). Even pretending that’s remotely correct, that’s about 14 million kWh in a day. If that were concentrated in one power grid, that might be meaningful, but it isn’t. It’s across the globe with many separate power grids and multiple sources for each and every one of them. Edit: a quick google says there are about 40 million EVs on the road globally, so using 5.5, it’s about 220 million kWh. But again, that’s spread across the globe.
So again, any future expansion would have already be well beyond any potential savings it could represent to them.
Looking at it differently, 5.5 kWh is less than 5 hours of charging on 110V, and less than an hour on 240/220/208, which is well within a nights sleep. And nighttime requires significantly less demand on the grid than the day. So your “needs less infrastructure expansion” argument doesn’t hold.
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You didn't seem to even understand your own question that you are attempting to answer here and ended up comparing apples to elephants.
You are comparing scenario 1 and scenario 2 as if they are the same thing, e.g. the same amount of energy, but they're not.
In scenario 1, you are talking about the very small amount of energy that could be produced by the solar panels.
In scenario 2, you are talking about the FULL amount of energy people would need to use in an electric car.
You talk about it as if doing scenario 1 is an alternative that would completely eliminate all of the cost of doing scenario 2 at all. The point you missed is that in scenario 1, that is usually not the full amount of energy of most people's standard use cases, so they will STILL need to recharge some (most?) from the grid as well. So grid capacity needs to be considered either way, and this tiny, marginal amount of extra energy that could be done from the solar panels could just be incorporated as a smaller not-very-significant additional cost into the grid work that will be happening anyway.
This was my long winded explanation that was more succinctly said here:
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These are not two scenarios. They're two separate issues and issue 1 relates to a single car and issue 2 to the renewable power (and charging points) that will be needed to boost grid capacity to meet the needs of a fully electrified economy.
The plan is to have ~100 million EVs on the road in North America, in the fairly near future. I've shown that PV solar panels, built into cars, could meet a substantial portion of the power needed, for the average daily commute.
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5.5 kwh at 4.25 miles/kwh will give my M3 about 23 miles of range based upon my average consumption. If the average EV, going forward in time, gets something similar, and the average commute is ~30 miles, we can see that this covers ~75% of the power required for a daily commute.
The plan for North America is to fully replace ICE vehicle production with EVs by 2035ish, so looking forward there will be ~100 million EVs on the road, in North America, in the fairly near future, and far more than ~100 million going past 2035 as ICE vehicles are fully replaced.
There are many EV owners, even today, who don't have access to even L1 charging.
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