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> I wonder if anyone associated with creating that image ever bothered to think about the heat that would be generated from all those panels and where it would go?
You're not thinking about it right. At the moment most of the energy falling on the earth is already converted into heat. With solar panels some would be converted to electricity, and then ultimately converted into heat somewhere else.
Solar panels as the only means to power the car and without storage will probably never be popular, but the OP's being realistic in saying it's more for simply extending the time and miles between charging sessions as well as the amount of power drawn from the grid. It's also possible that some of the power generated never goes through the battery and instead go to power various parts of the vehicle which can be good for the battery as it's that much less power being cycled through the battery which can improve its longevity. There's also the kind of parasitic draw that electrical subsystems have even when the vehicle is not in operation and having a dead battery after having left the vehicle unattended for a while can be mitigated a bit as noted here:
Quote:
Originally Posted by jtur88
But how about a solar-charged battery for the starter, so you will never have a dead battery when you try to start? Dead battery when starting has been, for 75 years, the number one bane of all drivers.
The question is really how much more do the solar panels add to the cost of the vehicle versus how much longer does it extend the range, lessen the charge times/amounts, and improve battery longevity. Trends over the last 8 years are that solar panels are getting less expensive and are much less expensive than eight years ago, EVs are overall more efficient for similar makes, and SUVs/crossovers with their long rooflines are becoming ever more popular. Meanwhile, there's been some advancement in very thin and lightweight solar panels as well as more efficient solar panels though the two don't always go hand in hand. So eight years later, things are looking a bit more promising.
Of the major automakers currently only Hyundai offers a solar roof option in the US. However, it's looking to have it as an option for its upcoming Ioniq 5 electric vehicle. These don't do all that much given the same constraints noted earlier in this thread, but they also aren't particularly expensive options.
More ambitious are a set of startups that plan to launch with more integration of solar panels into the vehicles, but they're still a couple to a few years away from launch and startups going into large scale manufacturing is quite difficult. Of the more notable startups, there's Aptera with its three-wheeler that is aiming for a maximum 45 miles of additional range a day, Lightyear with 30-40 miles maximum per day, and Sono with a targeted average of 10 miles of added range a day. These are some pretty hefty numbers for production targets of only a few years from now as these numbers do cover a significant amount of the average daily miles driven by the average US driver. However, these are still just targets and it's unclear if all or any of these will make it to production. If they do so successfully though, it would probably get the larger automakers and the general public to consider the option. Their targeted production dates are also pretty close to the window mentioned in this topic:
Quote:
Originally Posted by EA
"When is it going to be cost effective to have solar panels on electric cars"
I'd say 10-15 years. Solar technology is progressing pretty quickly.
GM had a solar powered car along time ago.
What model and brand? I thought most of them cut off the pedal assist at 20 mph for safety.
I revived a thread from a long time ago and the poster you're asking hasn't checked in for a few years now unfortunately. As far as I understand it, pedal assist bikes going over 20 mph are class 3 bikes and can go up to 28 mph but states have different restrictions that can make it so class 3 bikes require registration. From my experience, going over 20 mph on a bike doesn't really get you much. I do enjoy riding pedal-assist bikes, but not so much for their top speeds as it is for going over hills or if going long distances.
In regards to the topic of solar panels on EVs, it'll be interesting to play a number games once the stats come in for EVs with solar panels. I think once we get the stats of a year or so of use, the numbers game would be to then think about what happens when the price of the solar option, the additional energy generated by the solar panel on average over the course of a year, and the improvements in energy efficiency for an EV improve. For example, take the Ioniq 5 with a solar roof option and how its first year does. Then consider what happens when each of these improve by 10% which isn't that much of a leap where the solar panel option is 10% cheaper, the amount of energy generated over the course of the year on average is improved by 10%, and the efficiency on a miles per kWh basis improves by 10%. How much more worth it does the solar panel option become? Then what happens at 20%? Or 30%? Obviously these won't all happen in lockstep with each other, but it'll be interesting to try extrapolating numbers once the first mass production EVs with integrated solar panels are released.
These aren't crazy numbers when looked at from a historical perspective. Solar panel costs overall at least from a residential and utility perspective went down an order of magnitude (so around or better than 90%) over the last decade, both the current max in production and in labs efficiency of solar panels have gone up and there are currently production high end solar panels that are triple that of the average efficiency of solar panels in use now while EVs have some ways to go with the current average around 3 miles per kWh where there are production vehicle targets in the next few years for closer to 5 miles per kWh. A $2K option that adds 2 miles a day on average and slightly lowers the risk of your car not starting after being unattended probably isn't that attractive to most, but how much better does that get when it's a $1K option that adds on average 5 miles a day and greatly lowers the risk of your car not starting after being unattended for a long period of time? I think the latter part of this decade could be more than just the advent of the battery electric vehicle, but also the popularization of a practical solar option for such vehicles.
Last edited by OyCrumbler; 08-24-2021 at 11:17 PM..
I can only imagine all the solar panels in a city increasing the ambient temperature way up. As is is now, a concentration of paved roads, parking lots, and buildings results in a temperature increase in the cities versus rural areas.
I can only imagine all the solar panels in a city increasing the ambient temperature way up. As is is now, a concentration of paved roads, parking lots, and buildings results in a temperature increase in the cities versus rural areas.
That doesn't make all too much sense unless it was solar panels 1) in place of urbant trees / plants that produced a lot of evapotranspiration or 2) in lieu of highly reflective materials which would have reflected most of the solar irradiation which honestly isn't all that much material in the US urban landscape. It would likely be a pretty good improvement over parking lots though if lofted over the parking lots as it'd likely be less heat generated at that point with some part conversion to electricity and about as much or a bit more reflected than the asphalt.
I understand your concerns about the urban heat island effect and support minimizing such which is why it's a good idea to minimize running internal combustion engine vehicles in cities as much as possible. I'm glad you've come around on this!
Last edited by OyCrumbler; 08-25-2021 at 06:04 PM..
You think there are global warming issues now? Visit a solar energy farm in the desert and measure the temperature of the panels vs that of the ground next to them. That heat has to be dissipated somehow. Of course, some engineers will say the heat amounts to nothing. Same engineers that usually say other issues are of no consequence.
A study was done at a desert PV solar farm. They found 6 deg F increase in ambient temperature at the site. The heat dissipates rapidly away from the plant. At 100 feet the ambient temperature increase was not detectable.
It's a significant effect to be planned for but I don't see how it would cause a global warming issue.
A study was done at a desert PV solar farm. They found 6 deg F increase in ambient temperature at the site. The heat dissipates rapidly away from the plant. At 100 feet the ambient temperature increase was not detectable.
It's a significant effect to be planned for but I don't see how it would cause a global warming issue.
I wasn't talking about global warming, just about city ambient temperature warming. As it is now, buildings, parking lots, and paved roads in the cities do increase ambient temperature, specially during the hot summers. And yes, automobiles, air conditioners, boilers and furnaces, and so on add to the temperature increases. Now, lest say that in addition to automobiles having solar panels, more solar panels on buildings and other structures, and even solar farms, are installed in this city. That's what I am talking about. https://climatekids.nasa.gov/heat-islands/
The hottest places on Earth have a few traits in common. They are full of rock and stone, they do not have a lot of water, plants, or trees, and they are full of dark colors.
Cities are full of these rocky surfaces — asphalt, brick, and concrete — that absorb heat by day and release it at night. These materials are used to make the sidewalks, parking lots, roads, and basketball courts of urban areas. Urban heat islands form because humans replace cooler surfaces with rocky surfaces.
These hard and dark-colored surfaces contribute to the urban heat island effect in two ways. First, these surfaces have a low albedo, which increases the amount of energy from solar radiation they absorb. Second, these surfaces do not contain much water to evaporate, meaning that less of the absorbed energy evaporates water, and more goes into warming the surface and releasing energy by conduction, convection, or radiation. The combination of these factors means that cities and other highly developed areas are hotter than the plant-covered countryside.
I wasn't talking about global warming, just about city ambient temperature warming. As it is now, buildings, parking lots, and paved roads in the cities do increase ambient temperature, specially during the hot summers. And yes, automobiles, air conditioners, boilers and furnaces, and so on add to the temperature increases. Now, lest say that in addition to automobiles having solar panels, more solar panels on buildings and other structures, and even solar farms, are installed in this city. That's what I am talking about. https://climatekids.nasa.gov/heat-islands/
Right, so solar panels will have a pretty negligible difference compared to much of the rest of the urban environment, but will generate electricity. This really only makes a difference if this is solar panels in place of a good green roof or a highly reflective roof. Of course, the more efficient the solar panel, the less of it as an immediate conversion to heat, so maybe you're in favor of trying to opt for higher efficiency panels? That does make sense in the more limited space afforded by urban areas, and I think we're in agreement here. The study Elliot_CA mentioned was done when the average efficiency of panels were around 15%, but the average now is around 21%. I think in regards to EVs and the limited room they have, it may make sense to pay a premium for even higher efficiency panels which in turn would be less of the solar irradiation immediately converting to heat, so it's both functional and addresses your chief concern!
Right, so solar panels will have a pretty negligible difference compared to much of the rest of the urban environment, but will generate electricity. This really only makes a difference if this is solar panels in place of a good green roof or a highly reflective roof. Of course, the more efficient the solar panel, the less of it as an immediate conversion to heat, so maybe you're in favor of trying to opt for higher efficiency panels? That does make sense in the more limited space afforded by urban areas, and I think we're in agreement here. The study Elliot_CA mentioned was done when the average efficiency of panels were around 15%, but the average now is around 21%. I think in regards to EVs and the limited room they have, it may make sense to pay a premium for even higher efficiency panels which in turn would be less of the solar irradiation immediately converting to heat, so it's both functional and addresses your chief concern!
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.
The hottest places on Earth have a few traits in common. They are full of rock and stone, they do not have a lot of water, plants, or trees, and they are full of dark colors.
Cities are full of these rocky surfaces — asphalt, brick, and concrete — that absorb heat by day and release it at night. These materials are used to make the sidewalks, parking lots, roads, and basketball courts of urban areas. Urban heat islands form because humans replace cooler surfaces with rocky surfaces.
These hard and dark-colored surfaces contribute to the urban heat island effect in two ways. First, these surfaces have a low albedo, which increases the amount of energy from solar radiation they absorb. Second, these surfaces do not contain much water to evaporate, meaning that less of the absorbed energy evaporates water, and more goes into warming the surface and releasing energy by conduction, convection, or radiation. The combination of these factors means that cities and other highly developed areas are hotter than the plant-covered countryside.
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.
Last edited by RayinAK; 08-26-2021 at 09:35 PM..
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