A solar panel on an electric car is probably false green


Hyundai has put a solar panel on an electric car. Turns out that's "false green" and may end up using a lot of the solar energy to cool down the car after you park it in the sun. What do the economics on solar panels in cars look like?

See Hyundai puts a solar panel on an EV but it's probably false green


I might add that the cost in terms of damage to paint and upholstery from rain and UV would far outweigh any small electricity saving benefits.
I pity the engineers who had to swallow their pride and do it anyway despite knowing it was pure nonsense.

Electric car sales are increasing. One day the two-hour traffic jams on the freeway might consist primarily of electric vehicles. A solar roof on a car can keep the vehicle moving at an acceptably slow rate as long as the sun is shining and might avert a traffic tie-up. This is probably better than the use of helicopters in Korea to remove disabled cars in the middle of traffic jams. By the way what percentage of vehicles come with glass roofs? Very few. Glass can also be made photovoltaic.

Some European countries have laws banning gasoline and diesel cars by the year 2030 or slightly later. The writing is on the wall. Forbes should be more positive on the industry.

It's not at all certain it could keep the cars moving at a slow rate, or that it would need to. Unless the traffic jam lasts for a month.

I'm not sure what you're reading, but I'm super positive. I'm just not positive about gimmicks for people who have not done their math.

An entire fleet of solar-powered cars annually traverse both the US and Australia. Some of them can move at 50 MPH for most of the daytime. They are generally university projects.

It is not a question of math. It is more an issue of being well-informed.

It discusses the World Solar Challenge.

This idea of some solar cells incorporated into the roof of a car is a reality, and a good idea. I HAVE SUCH A CAR, my 2011 Toyota Prius came with cells built into the roof, around my skylight. The dont run the car, or extend my driving. What they DO do is run a circulation fan inside my car when it is parked. And it's fantastic. My interior is not blazing hot as it would be with still air. It is a fantastic addition to any car, electric or not. The fact that you could extend your drive time a bit due to input from the cells during driving or in stop/go traffic is a reality also, but I am not sure of the actual miles you would add to your range, probably small.

A Tesla loses about 2 miles of range every day. So, if you leave your car sitting for to long it can drain and destroy your battery. This can save your battery. It needs to have the capacity to both save the battery and keep the car cool though.

Yes, if you plan to park a Tesla for a long period it can drain and this might help. Though the amount it loses varies (for a while I was losing 10/day with no apps with access and no sentry mode.)

However, Tesla could implement a storage mode that goes into a hard shutdown, possibly waking up once/day or just waiting for a physical handle flip to power up, which would take a minute or two. Then it should be able to sit for quite some time unplugged.

But is the function of keeping it charged worth what this panel costs? I would have to venture a custom molded panel fit into a roof and robust enough to handle the car environment is a pricey thing.

Rather than speculating what the cost of the panel is, you should have requested from Hyundai the actual cost and performance - then write your evaluation of it with all those factual numbers included. My non-electric Audi has a solar panel on its roof, and it does help to keep the interior cooler when parked in the sun. For that reason, I am willing to pay more for a car with a solar panel here in the American southwest desert.

But it's the answer that one suspects one won't get the answer to. The point is, it's definitely going to be more than a panel built for a rooftop or solar farm installation. Much more.

But yes, it's a reasonable thing to have for cooling a car, and I say that. Other cars have had that before. But people treat it like some sort of solar powered driving, which it is not.

When electric cars with panels are around in huge numbers, then each one is consuming a little less power from the grid.
Millions of small solar panels adds up to a decent amount of power that doesn't need to be generated from coal. Its like a power station that everyone bought a small part of.

Connecting residential solar to the grid is a false green actually. The grid will happily pay you wholesale rates for power during the day while charging you retail at night when you use it. YMMV, but that's about 33% efficient where I live.

And solar panels are already super cheap, it is the installation, inverter and fees which are expensive and wreck the payback. Installing solar on my roof would also be about 33% efficient. As in most of the money is spent on things other than the panels themselves.

So putting a solar panel directly on top of a battery - as in an EV - on a product which is mass produced, actually makes quite a bit of 'green' sense. There is more to it than the extra miles you get.

It is much better if all those solar panels, instead of going on the cars, had that money go into putting them in solar farms. That's what I do -- I buy all my electricity from solar and wind farms. Every dollar I spend on electricity goes to pay to increase the size of solar and wind farms. Many other people do that. Much better I fill my battery from grid energy, bought from solar farms, then pay much more to put a panel on my car.

Well, almost. The one catch is that where I live there are obscene delivery fees except at night. So I only charge at night. Actually, they are bad at night, but still cheaper than a panel on the car.

And no, residential on the grid is not false green at all. Yes, utilities will screw you, but it's still better to sell your excess power to them at their crappy price and offset fossil plants by doing so. However, if you have a clever charger, you can also put that excess into your car if it's plugged in.

Yes, if you have cheap land then solar farms are a great way to get more PV for your money - simply because the economy of scale makes it more capital cost efficient. The solar farm still has to use the grid though, which as you say, does still cost you a big chunk of money.

And as the grid becomes more and more saturated by people charging their EV's at night, what do you think will happen to your night rate?? Of course, they will start to charge you for it like they do in the daytime.

And all that is not the same as residential solar of course, which is what I specifically mentioned.

However the _best_ investment will always be to put the panel directly on top of the load, where it will generate the same or less than the amount of energy that the load demands. That will beat your solar farm as it doesn't need to use the grid - and it doesn't require batteries or storage like your nighttime solar/wind purchased power will.

A good example of this is industrial sites. They have enormous power demands and most also have enormous roof areas for solar.
These operate during the day. That is when the sun shines, so no need for the cost issues of using the grid. And the installations can be large, so again, more PV for your money.

So, a micro example of this is a solar panel on the car. Tiny area, but since it is mass produced the costs can be much lower. It is micro generation. Shading is a problem of course, but you have pointed out yourself how much you suffer from the grid.
If you put the panels on your own roof, feed the grid during the day, then pull power at night to charge your EV, then you throw away about 66% of the money. 66% of shading is a lot.

There is no reason why solar on a car should be an expensive option either. It is right now, but it is brand new. If it happened in volume the price will drop significantly. Mass production.

This is indeed generally a good idea. But not as much when putting the panel at the load comes with a lot of extra costs, as installing things in a car roof and hood does. The grid/house panel will be tilted up at the sun, and placed to avoid shade, the car panel will be flat and moves around and prefers shade if you can get it. All these factors overwhelm the usual rule about putting the source near the load. Perhaps today you always park in the sun -- will that be true for the life of the car? Might you change to a different home or job where you can't or don't want to park.

Nobody is talking, but I have to believe that a panel mounted in a car roof costs several times one one costs added to a solar farm or household roof. It has to have a special shape. It needs cooling. It has to withstand heavy vibration.

The only reason the grid isn't an overwhelming win is places where the grid is super expensive. Fortunately those are in the minority.

Note that the panel is not at the load, it's charging the battery. Most people drive only an hour or so a day -- the energy generated while driving is trivial.

Yes - in the case of an EV I am considering the battery as the load for the PV panel. That is one of the big opportunities here - the battery is there already. For any other solar system the battery is an additional cost.

And yes the practicalities and costs are not publicly known. I would really like to know if there are any significant issues that Panasonic have not been able to solve in their solution. It is on a couple of different production vehicles now, and the price of the option has dropped - from what I read.
Plenty of RV's are driving around with ordinary residential solar panels on their roofs, so I don't think it is particularly challenging problem from the vibration standpoint. I've done this myself.

The efficiency of the PV panel on an EV is not important on its own. What is important is to look at the efficiency of the system as a whole.
IMHO it is not logical to accept the poor cost efficiency of the 'grid as a battery', yet denounce the poor insolation of PV on EV. In actual fact I think they probably roughly cancel each other out.
And it is the collective of PV equipped EV's which add up, not just your car or my car and where you or I may park.

The grid is generally expensive everywhere I have heard of, aside from some places with artificial or temporary situations. Temporary situations are ones which are easily taken advantage of and so will return to a norm - for example a very cheap night rate vs a very high day rate. It would make sense to just get a battery and buy and sell power at different times, instead of bothering with installing a solar system. Artificial situations like subsidies tend to disappear as quickly as they arise once people take advantage in large enough numbers. If you can leverage either of these then great. Make the most of it while you can I'd say.

Mass production of installed PV is the key. It is a well solved problem to mass produce ordinary solar panels, but no-one can mass produce the installation of them.
Every install is custom and costly, needs to be certified, and requires expensive extra hardware like inverters. On EV's, manufacturers can pump them out in large numbers, which drives down the cost, and that is the opportunity here.

I quite agree with everything said here except that grid connected solar is in any way false green.

Looking out my office window at the sea of cars in the parking lot, I thought the exact same thing as more and more of those vehicles become electric, those few miles of solar per vehicle each day could at up to quite a bit of electric energy produced in aggregate.

The solar panels in the Sonata roof are curved, so are likely flexible solar panels, which are quite cheap to produce. The added "cost" on a mass produced vehicle, would be negligible, a few hundred dollars at most certainly no more than other common features often found on cars.

The plug-in Sonata has a fairly short electric range, only about 28 miles, so under most driving conditions would often be reverting to Petrol power. At current gas prices, even just those few extra electric miles vs gas powered miles could easily pay for the solar installation in only a few years.

Grid connected solar is not false green. It is off-grid that usually is.

Now, if you want to get strict, if you are truly interested in being green, then your goal should be to cause the best improvement to the environment for your dollars and efforts. In that case, there are still a lot of things which do that better than putting solar on your roof, though putting solar on your roof is getting higher and higher up the list.

One obvious thing is to put solar on the roof of somebody in a place with coal power and lots of sun. New Mexico and Arizona were the prime places, but they are getting cleaner grids. Solar panels here in California mostly offset natural gas. It's many times better to offset coal if you can.

However, there is still really good bang for buck in replacing incandescent bulbs with LEDs, replacing 20 year old fridges and a few other types of negawatts.

Solar on our roof makes us feel good though, and with the tax credits can save money, which leads many people to do it.

It seems that putting solar panels permanently over top the parking spaces would be strictly better. I'm not sure how it compares to residential rooftop solar and solar farms, but it's gotta be better than putting solar panels on your car, and it uses roughly the same space. Perhaps best of all, you can have it over top all the parking spots, so if only 1/5 of the cars are electric they can get 5 times the charge (more, really, since the generation will be more efficient). If there are any electric cars parked there that need power, those cars can take it all. If there are none, or more power is being produced than the few cars can handle, the excess can go to the grid (or to the nearby offices). You could, of course also, or alternatively, offer faster charging, probably for a fee, but free trickle charging of whatever is available is probably a good no-additional-charge perk to offer.

That probably goes for RVs too, at least if you stick to parking mostly in designated RV parking spots. If the RV park itself is disconnected from the grid it could have a relatively small battery (for when excess power is being produced).

You mention the waste of power when the batteries are full. If the batteries are full and the car is parked in the hot sun you could run the A/C for a minute or two, I guess.

The roof the carport may be good, it may not be. The primary place is south or western faced roofs, tilted to match your latitude. South for maximum energy, west for max energy at peak power cost times. If the carport roof is suitably tilted or sunny, it's good. If not, find a place like that on the regular roof.

Yes, you can run AC with "spare" power but that's effectively wasted. For a large solar array, you will get a fair bit of waste if it tries to go into batteries. One "plus" about the small one you can put on a car is that it just can't produce that much power, and thus is unlikely to fully charge the battery. When it only makes 600 watt-hours in a day, about 1% of the size of my battery pack, it's OK to let it bump up from 80% (my normal top charge) to 81% or even 82% if I park for a few days. (And as people note, Teslas are way too power greedy when off and would use this up.)

For the carport I was mostly thinking about new installations. I'm looking right now at a parking lot full of cars in the sun. Instead of putting solar panels on some of those cars, why not put a roof over the whole lot, or significant parts of the lot?

Obviously one reason is that the trade-off is not direct. The owner of the lot would pay for the roof, whereas the car owners would pay for the car panels. But it seems like it's be a good perk for the lot owner to offer. Alternatively, they could charge for the power, or use the power at the shops in the strip mall, or sell it to the grid, though each of those options comes with overhead compared to just letter EV cars get a free trickle charger as a perk. They still can sell to the grid (or send to the shops in the strip mall) whenever there's not enough demand from EVs parked there.

Ditto for office park parking, which is what I was considering initially (but at the moment I'm in a strip mall restaurant). The office lot is probably a better location, as the view from the restaurants might be hurt by the solar panel installations (though the view isn't particularly good anyway).

My presumption is that building a roof for a parking lot is somewhat expensive, certainly more than having existing roofs, or just plain ground to mount the tilted panels on.

Actually, while I have criticised the car panels for being horizontal (a loss of about 30% over the proper tilt) as the panels drop in price, it will reach the point where flat on the ground is cheaper than tilted, at least for solar farms, because there is minimal install cost. Other factors are hard to calculate -- it would be harder to keep flat panels clean, and there might be more fire risk with cables lying on the ground. In some areas land is cheap, though, cheaper than mounting hardware.

Interesting. I was guessing the cost was not much more than the cost to install the equivalent number of panels on a car (which can't be cheap either).

Whether or not it's profitable, I can't say (solar still is only profitable in certain locations, depending on amount of sun and perhaps more importantly government subsidies and quasi-government subsidies like net metering). But profitable or unprofitable, I figured it'd have to be better than the dumb idea of putting panels on a car.

Actually, basic panels are quite cheap now. In a growing set of places, new solar plants are the cheapest type of new power plant to put in, as long as you don't have to worry about storage (which you don't so much for cars.) Solar farm is the most cost effective approach, though subsidies and bad distribution charges can change that.

The instinct some people have, when thinking of a solar panel on a car, is that the closer the panel is to the user of the power, the better -- and that's generally a good instinct, but other factors can overpower the value of that.

Panels are only a fraction of the cost of solar.

But yeah, I'm sure solar makes sense in some situations.

And in other places it requires subsidies. Apparently you agree with that, since you're willing to pay extra on your electric bill to try to get people to build solar plants in places where they'd otherwise not be economical.

If they'd already be economical, there'd be no need to earmark your money.

There are different meanings to economical. In many places, the cheapest way to get power is to use an existing power plant with low fuel costs, which is nuclear, and hydro, and of in many places natural gas. Solar is cheaper than natural gas now in places like California if you debate putting in a new NG plant vs. a new solar farm. However, the NG plant has other costs that I am not paying but which I don't want to place on others. Is that a subsidy?

Anyway, the cost at my power company for all solar/wind is about $7/month. It's not big at all.

Making cars with my idea of ​​air fuel

It's all in the marketing. Sadly, many people are bad at basic math or critical thinking -- especially if it appears 'Cool'.
I was asked why I didn't put solar panels on my house. I use $50/month or $300/yr of electricity. With rebates and tax incentives, the cost is still in excess of $10K. My breakeven at 0% inflation is 30 years. I did much better upgrading my appliances.
Solar does make sense in some instances - but you have to do the math!

The solar panel on this car looks to be about a 250 watt system. Because it is horizontal, even in a sunny location it might average about 1 kW a day. Which equates to 4 miles of travel. That is also not taking into account that the DC solar panel to DC battery charging may be more efficient. But clearly it isn't enough to get you very far.

Someone posted the suggestion of a solar carport. Assuming 10'x20' structure with panels tilted appropriately, a carport in a sunny part of the country could average more like 15 kW per day and offset a 60 mile commute.

The reality is the electricity for propelling these cars needs to come from somewhere. It may not be feasible with current technology to power a vehicle with attached panels but I don't think it is quite right to call it False Green either.

I call something false green if there's a better way to do it, and people do something else because it makes them look or feel better. People like the idea of solar powered driving. They really, really crave it. But the reality is, what you should do if you want to be green is get the most green energy on the grid for your dollar. If you have $100 to spend on green energy, you can put it into panels on your car, or you can put it into panels on your carport or you can put it into paying for electricity for a solar farm. Putting it on the car is not going to be the winner, not even close. It's just to make you feel you have solar driving. That's false green.

this isn't about feeling green. it's for people who can't plug their cars to power when they go home and don't drive it everyday, i.e, a lot of people.

this is written from the perspective of someone who drives their car everyday (for 1-2 hours!) and has a garage to charge it at. i.e your typical american suburban professional who has a house and drives into the city for work. There a lot of young people who live in cities and rarely drive their car, maybe once or twice a week to buy groceries etc. And others who live in apartment buildings. Many cars sit parked for days. It will be very useful for anybody who doesn't live the TV american lifestyle.

Well, the average car is driven under 40 miles/day, and yes, my car is around that and yes, it often sits a day or two. However, while it does often sit in the sun, if I could avoid that, I would. Sitting in the sun ages a car, and makes it hot when you get in it.

For people who rarely drive, a very expensive electric car is not a good choice quite yet. One of the big advantages of an electric car is you save a lot of money over gasoline. But not if you don't drive.

One question I have for you Brad, is regarding something you mentioned yourself in the article: "if solar becomes cheap or efficient enough to put everywhere, putting it on a car might make sense". Currently, it does not, it is still "relatively" expensive and not extremely efficient, but what if I told you that eventually there will come a time where it will indeed be cheap and efficient enough to justify its use in vehicles? Wouldn't you think that the companies that started ahead of time, further elaborated on the concept of vehicle applied photovoltaics and developed technologies on which they will be exclusive on the market, wouldn't you think that those companies now investing time and money to work towards that vision were right? You also do know that skeptics or EVs said basically the same thing as you do right now 10 or 15 years ago about companies such as Tesla? Technological evolution is not always about the "current" potential of the technology itself but rather its potential in the years to come, so that when the time will be right, companies developing these technologies will be years ahead of the other companies not believing in the current potential of the technology.

Yes, I am aware of projects to make much cheaper and efficient solar. Maybe they will happen, maybe they won't.

I don't think companies that do it today, when it makes no sense, will win should be start to make sense. The gain is only minor, after all. Your car has an area of perhaps 7 square meters it can horizontally expose to the sun when it's sunny and not in shade. At 60% efficient, you could generate about 400 watts per square metre of horizontal surface under the best circumstances, or 2800 watts.

2800 watts would be nice to have, but it's only modestly nice. Sure, you would do it if you could get it (and didn't want a sun roof etc.) but it's not going to make your car an instant winner before companies start offering this as an option. If they offer it at all, since it is still not an obvious win over the other desires people have for cars they park in the shade, or with sunroofs, or with certain looks. And if battery tech gets better it may not get you that much.

What a terrible article. Just because it's not the most absolute ideal use of a solar panel doesn't mean it shouldn't exist. I don't see the average person trying to make the most ideal use of their plastics, or the most ecologically ideal choices for their food every day (buying produce from South America, blah blah) or even THINKING about what the meat they eat does to the environment (guys I love meat too), so why the hell would you hold solar, something we need and that provides obvious benefits, to that kind of absolute standard. Pure rubbish.

As noted, it's convenient, so it can exist. The point of the article is it's not a green choice, and many people don't realize that. If you want to reduce emissions with your money, which is what a person who wants to be green does, then you want to do it effectively, not wastefully. Or you balance that with the convenience.

One of the biggest problems is that it's extremely expensive to reduce emissions simply by paying money. For instance, adding solar panels to your house is okay, but adapting your energy usage so that you use more power when clean energy is available and use less power when it isn't, is much better, and ultimately will be necessary as a society if we truly want to reduce emissions globally. But the latter requires more difficult lifestyle changes, and not just throwing money at the problem.

Similar things are seen when people think that "recycling" is a complete solution and forget about the "reduce and reuse" parts of the formula.

I want to reduce emissions, but I'm aware that I can't do it with my money alone. Reduce and reuse are more important, and along with that comes things like eating less meat, using less plastic, driving less, etc. There are sometimes monetary costs as well, though often you can actually save money while being more eco-friendly, by making certain lifestyle changes.

Finally good to see someone seeing through the hype and marketing of the idea of placing a solar array on the roof of a car. We have a 6.6kw array on our house with close to optimal angulation in the Australian sunlight and it goes somewhere towards powering an 11.7kwh battery in my PHEV. The idea of maybe 400w panel suboptimal placement to have any real effect on an EV is farcical.

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