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Even if there aren't any ICE vehicles of any kind in the city, the ambient temperature in the city will still increase, because buildings, roads, parking lots, glass windows, metallic roofs, and the rest absorb heat during the day and release it at night. Read the NASA articles I posted above in relation to what causes the increase of ambient temperatures in a city (buildings, parking areas, and paved roads are the main reasons). Glass and other reflective materials reflect heat and light.
You are talking about ICE vehicles without taking into consideration the heat produced by air conditioners during the summer, nor boilers and furnaces, power plants, aircraft at the major airports, and on and on. Those very tall buildings in the city have very large AC units. Also any electrical equipment, lighting, and so on create heat, because electricity dissipates in heat.
By the way, I am not worried about such things. All I am trying to say is that adding more solar panels, regardless of kind, also contribute the the ambient temperature increase in the city versus rural areas that have lots of grass and trees.
I'm not sure why you bold'd what you did given that I mentioned the urban heat island effect and the papers I posted were studies that specifically dealt with the matter. Am I supposed to assume then you haven't bothered reading my posts when you replied? No one is saying that ICE vehicles are solely responsible for the urban heat island effect, but their inefficiency and the dense concentration of them makes them rather notable contributors as do the infrastructure built around supporting them. Like I said earlier, adding solar panels in urban areas is unlikely to add more to the urban heat island affect unless its in replacement of fairly pristine white painted or reflective material roofs (sometimes called cool roofs) or over certain plants or green roofs--in which case, don't replace those with solar panels unless there's a particularly good reason to. The last case of green roofs or green lawns in general is interesting-the albedo of grass lawns is close to the net albedo and conversion efficiency of current solar panels (which have improved to an average of 21% today). However, as mentioned in an earlier post if you read it and which I posted before your links which also mention it, there's the effect of evapotranspiration where water is drawn from the soil be the plants to the surface to evaporate and cool off. Hence my mentioning an example of solar panels replacing or overlaid on surfaces that are *not* greenery or white painted roofs. One thing to also understand is that more efficient solar panels would mean less of that sunlight being immediately converted to heat hence papers like this one about the urban heat island effect actually being reduced with solar panels: https://www.sciencedirect.com/scienc...386?via%3Dihub https://www.frontiersin.org/articles...014.00014/full
In relation to vehicles, this means that the solar panels integrated into the roof and/or hood of a vehicle could be better or worse than one that's just painted depending on the color of the car (well, more specifically the albedo) and the efficiency of the solar panels. It will do better against darker colored vehicles like a black or a burgundy or brown, but worse against a bright white, and the efficiency of the panels essentially moves the line on which colors (albedos) it does better against. The more efficient the solar panels on the vehicles, the larger the variety of colors it does "better" against.
Here's a look at the Sono Sion which has been in works of sorts since 2012 and is projected to do customer deliveries in 2023 (though to the EU--no projected date for the US and there is a possibility it never comes here since it's projected to be small, fairly affordable, and not a crossover, SUV, or pickup). Projected average 70 miles or range added per week by the solar panels in not so sunny Germany, max 150 miles added per range from the panels, able to charge other devices including other vehicles at up to 11 kW, uses a 54kWh LFP battery that gets 190 miles on battery only (WLTP), 75 kW max fast charging, motor outputs 160 hp and like all EVs delivers a lot of torque from the get-go, price is about $25K USD without tax or incentives:
Even if solar panels get MUCH cheaper, they will have little influence on charging batteries for electric cars. The produce a tiny amount of electricity, all things considered. A panel 2 x 5 (feet) produces just 127 watts. Such a panel can almost charge one 12V battery in one day. Such a panel would take about a month of all day sunlight to charge a Tesla battery.
This does make me wonder if solar panels could be more impactful for the Tesla Semi? If the semi truck and trailer are covered in solar panels would that be enough area to have an impact? Maybe it wouldn’t be enough to self-charge but could perhaps help to extend its range some?
i seriously doubt it will ever make sense to put solar panels on cars. you would be driving around tons of extra weight for no reason. any energy you captured would be eaten up by the hundreds or thousands of extra pounds you'd be driving around.
This does make me wonder if solar panels could be more impactful for the Tesla Semi? If the semi truck and trailer are covered in solar panels would that be enough area to have an impact? Maybe it wouldn’t be enough to self-charge but could perhaps help to extend its range some?
It's possible--it just depends a lot on whether it's worth the cost. And yea, pretty much all serious mass production proposals for solar on vehicles is about extending range rather than exclusively powering through the solar panels only.
Quote:
Originally Posted by steveklein
i seriously doubt it will ever make sense to put solar panels on cars. you would be driving around tons of extra weight for no reason. any energy you captured would be eaten up by the hundreds or thousands of extra pounds you'd be driving around.
Sure if it's tons of extra weight for no reason. You'd want that extra weight to do something. Whether it's worth it will depend on the cost of the solar panels to be installed and the potential extra maintenance, how much power is generated, and how much weight is added. Solar panels certainly don't need to weigh very much depending on what type of panels they are and the inverters have gotten a lot cheaper and smaller. Eight years in from this topic's first posting, solar panels have gotten much, much cheaper in terms of the modules and the efficiency averages have bumped up from about 15% to about 20% and there are some pretty thin film solar cells now.
One trend that's interesting is that as the cost of the solar hardware itself has plummeted over the past decade, the proportion of the average solar installation's cost has leaned more and more towards the soft costs of land acquisition, installation, and permitting. If solar module's keep going down in cost, then those soft costs take up an increasingly large share of the total cost. That's interesting in terms of vehicles, because that land acquisition and permitting bit is either nonexistent or quite different and the labor of installation if part of a standardized and mostly automated installation procedure within the more predictable confines of a vehicle assembly line could make it so that the costs for solar on vehicles is actually quite a bit cheaper after the initial research and development than one might expect.
It'll be interesting to see what the solar panel equipped cars actually do in the next few years. There are the startups that have them built in by default like Sono Motors and Lightyear, but there are also major automakers like Hyundai giving this a go with the Hyundai Sonata hybrid and the Hyundai Ioniq 5 BEV. I read that the Sonata allows the solar roof to come as an unbundled option in South Korea (rather than throw them in as a large, higher trim bundle as here), and that the option there costs an additional $1,100 and the weight of the solar roof is 66 pounds which is slightly higher than the plain roof and slightly lower than the panoramic roof. There's certainly some wiring and an inverter that needs to go in there, but at 204 watt capacity, it's not really that much and so the entire system's additional weight is likely to be closer to 70 pounds, so if the vehicle is even moderately efficient, then it's going to be a net gain there as that additional weight in a vehicle doesn't factor strongly for a vehicle as efficient as a hybrid. The question is really then is the net gain worth the price. The fairly small Hyundai Sonata's rooftop panels supposedly can get you probably on a conservative average of half a kWh a day. If this were extrapolated to a BEV, then if you're getting 4 miles per kWh, then you're talking about 2 extra miles a day for $1,100. It does a little bit of other things since Hyundai's design allows it to go straight to auxiliary power rather than always through the battery, so you're also making it so that you don't have parasitic drain surprising you with a low or dead battery if you haven't touched the vehicle in a while and a little bit more battery longevity as the power those auxiliary bits would have drained from the battery are now no longer part of the battery's duty cycle. Still, it's a pretty small benefit for $1,100. However, solar panels have gotten cheaper and more efficient over the last decade and BEVs supposedly can get more efficient as well especially with lighter batteries, so let's say you double the output of the panels (via a combination of more efficient panels and adding one more panel than the Sonata given the Ioniq 5 is a crossover with a tall roof) for a future iteration of an Ioniq 5, but at the same time dropped the effective price of the solar unit by half while the unit remains negligible in additional weight. Let's also say that the next iteration of the vehicle itself is more efficient, slightly better than the industry leaders now, and does 5 miles per kWh. So that's 1 kWh per hour yielding on average of 5 miles of range top-up for $550. Well, at that point, this does seem like a much more attractive option.
Last edited by OyCrumbler; 10-02-2021 at 02:53 PM..
Even if solar panels get MUCH cheaper, they will have little influence on charging batteries for electric cars. The produce a tiny amount of electricity, all things considered. A panel 2 x 5 (feet) produces just 127 watts. Such a panel can almost charge one 12V battery in one day. Such a panel would take about a month of all day sunlight to charge a Tesla battery.
Yes, that is true - the output of solar panels on say the roof, or even the hood as well, is relatively low, even under ideal conditions. So for a conventional EV weighing about 4,000lb, in less than ideal solar conditions - parked indoors or parked in the shade, frequently cloudy climate, a latitude with short winter days, etc - solar charging won't do a lot.
There is a small, lightweight (~ 2,000lb) 3-wheeled aerodynamic vehicle being developed by Aptera that has solar cells on it, and that may make a meaningful contribution if it's always parked outside in a sunny region, but that is a super-efficient vehicle with low power requirements. Aptera claims 5 miles of range per hour of solar charging, which is actually pretty good if you live in Arizona - leave the car parked outside where it's not shaded and once you charge it up from the wall, it may largely charge itself for moderate daily commuting and errands. https://www.aptera.us/
The problem is not the solar panels output. The problem is that modern society needs a 3000lb car going 70mph.
I have $150 in solar panel charging my electric bicycle. Rarely need to plug into the wall. I get about 20 miles a day of sun ebiking with no pedal input (but I do pedal when I feel like it).
So I have a $1200 investment in my electric bike and solar panel and it pushes me around 100-140 miles a week on solar power.
It also doesn't get stuck in traffic. And it goes 25+mph.
What is your solar charging setup for your e-bike??
Yes, that is true - the output of solar panels on say the roof, or even the hood as well, is relatively low, even under ideal conditions. So for a conventional EV weighing about 4,000lb, in less than ideal solar conditions - parked indoors or parked in the shade, frequently cloudy climate, a latitude with short winter days, etc - solar charging won't do a lot.
There is a small, lightweight (~ 2,000lb) 3-wheeled aerodynamic vehicle being developed by Aptera that has solar cells on it, and that may make a meaningful contribution if it's always parked outside in a sunny region, but that is a super-efficient vehicle with low power requirements. Aptera claims 5 miles of range per hour of solar charging, which is actually pretty good if you live in Arizona - leave the car parked outside where it's not shaded and once you charge it up from the wall, it may largely charge itself for moderate daily commuting and errands. https://www.aptera.us/
Right, local conditions and context matter a lot as does efficiency of the vehicle itself. People in more northerly climates might want to go for sunroofs or panoramic roofs more so than solar roofs as the benefits of a solar roof is lower and it might be nicer to have the sunlight come into the interior. I do wonder if there are going to be sunroofs where the shade that can be mechanically drawn and embedded with solar panels would make any sense. There's also the possibility of using far less efficient transparent solar cells.
There's also the Sono Sion supposedly up for release in 2023 and going for a max of 24 miles a day. That max will probably rarely be reached, so getting half that seems more reasonable which would be 12 miles a day. That's not enough to cover an average commute, but it does cover maybe a third which for an average US commute means getting two and a half days of commute roundtrips for every week of commuting.
I've started to think about this somewhat in terms as being analogous to buying the non-plugin hybrid version of an ICE vehicle which gets you just a bit more "effective efficiency" for a higher upfront price and possibly more maintenance, but doesn't radically alter functionality. I think where it's better the hybrid analogy for a lot of vehicles is that the hybrids often perform differently than their straight ICE counterparts and often come with slightly more sluggish performance whereas the solar doesn't much affect performance aside from a fairly small modicum of additional weight. The savings on time and "fuel" compared to the respectively more conventional vehicle also work differently since the solar panels essentially max out based on the sun whereas the hybrid essentially nets more savings vs the straight ICE based on miles driven. For a person driving relatively few miles, the solar panel can potentially cover a large portion or even the entirety of their trips, but the proportion of those "free miles" diminish with more miles driven a day outside of the solar generated power while the hybrid saves fairly little if driven fairly little so may take a long while to recover something equivalent to the price premium of the hybrid.
Last edited by OyCrumbler; 10-05-2021 at 08:32 AM..
Some vehicles have integrated solar panels. The Hyundai Sonata Hybrid comes to mind. They only add something like one KWh into the battery with strong sun over an eight hour period.
If you’re wanting to charge an EV using electricity generated from solar panels, then you’ll need a rooftop or array system and a large one at that. We have one and a Chrysler Pacifica [Plug-in] Hybrid. We live in near Dallas which gets more sunlight than the US average. It is south-facing and is about 1,200 square feet. My husband can charge our van at work for free. For some perspective, we actually put electricity back into the grid if he charges at work. When we charge at home, the solar system only covers about 75% of our electricity need.
Some vehicles have integrated solar panels. The Hyundai Sonata Hybrid comes to mind. They only add something like one KWh into the battery with strong sun over an eight hour period.
If you’re wanting to charge an EV using electricity generated from solar panels, then you’ll need a rooftop or array system and a large one at that. We have one and a Chrysler Pacifica [Plug-in] Hybrid. We live in near Dallas which gets more sunlight than the US average. It is south-facing and is about 1,200 square feet. My husband can charge our van at work for free. For some perspective, we actually put electricity back into the grid if he charges at work. When we charge at home, the solar system only covers about 75% of our electricity need.
The Prius has used solar panels on some production models, but they didn't do too much. Here is a 2019 report on an experimental system Toyota was evaluating. The reported solar panel efficiency is 34%, which means those are not conventional solar panels, and they will carry a significant price premium. At least under the conditions they tested, they concluded they could get about 30 miles of extra range per day on the Prius with that (currently cost prohibitive) setup.
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