Toyota Motor Corp. is secretly developing
 

Soruce: Toyota working on solar-powered car, paper says

Uh, yeah. On a sunny day, the intensity of sunlight hitting the Earth's surface is an average (over a sunny day and with consideration for the angle of incidence) of about 500 W/m^2. That means the most power you could hope to collect with a square meter of collection area is 500 Watts, and that's assuming no losses in the solar cells. In fact, even the most advanced solar cells struggle to do better than 30% efficiency, so we have then about 150 Watts per square meter.

Now, let's say we need about 30 horsepower, on average, to use for about 20 minutes one way to work (I'll assume it's a flat place, the car is pretty streamlined, and we're not in a huge hurry). 30 hp is about 22.4 kW, and since we want to produce that power for 40 minutes (to work and back home again) we will need 22.4kW*40minutes*60sec/min=54000kJ of energy.

OK, so we have 150 W/m^2 of generating power, and realistically we should have about eight hours of sunlight that's not at very oblique angles to the solar panels.
For every square meter, we will get 150*8*60*60=4320kJ of energy. Uh oh.

For each one square meter, on a good, sunny day, I will capture 4320kJ of energy, if I can store it in batteries without any conversion or storage losses. But I need 54000kJ. No problem, I just need, er, 54000/4320=12.5 square meters of solar panel on my lightweight, streamlined car.

Now assuming my car can only be two meters wide to fit on public roads, my car will include an uninterrupted solar panel that is about 6.25 meters long sitting on top. And I still won't make it home on an overcast day.

Totally solar-powered car? Better have a solar generating station to plug into somewhere.

Now of course there have been solar-powered cars for races. They can move at 60mph all day on flat ground because they do not need anything like 30hp to do so. But these things are flyweight vehicles that would never, ever be seen as safe or practical, even for the most diehard extremist.
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That is why they are developing it. Have to try stuff to get it to work. Yes with todays tech. the consept is out to lunch. but 40-50 years down the road who knows. Come on you build and design rockets. you must think out side the box sometimes.

Actually, I'm now seeing solar panels available to the consumer market with efficiencies as high as 45%. They're expensive mono-crystalline, but they're still 45%.

I understand what you're saying about the amount of energy it takes to move an electric car, but what you're forgetting to realize is that it doesn't only gather energy during use.

A) The car can be collecting energy all day while the car isn't in use.
B) They do say that it will be solar and grid charged.
C) If you have a full traction pack and you begin driving, solar power can help off-set the amount of energy used over time.

It's a good idea to me. Although, it's good that you know your math. I've done research on this too.

Of course, but I also have to work within the laws of physics. Toyota will not get more than 500 W/m^2 even if they spend money for another fifty years. They will not get a practical car down to 400 pounds with a drag coefficient under 0.1 either. Sell me an efficient car, yes. Environmentally sound, good. Personally I'd love to commute to work using the energy that falls on me every day (very evident in the desert!) but I'm saying that the energy has to be collected by large areas.

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Crash:

OK, stipulated that solar cells will reach higher efficiencies, say even 70%, but that won't change my areguement, it only makes the car shorter, so to speak.

A) The car can be collecting energy all day while the car isn't in use.

I included that. 40 minutes of driving, verses eight hours of collection.

B) They do say that it will be solar and grid charged.

Grid charged is not 100% solar power unless the grid is 100% solar.

C) If you have a full traction pack and you begin driving, solar power can help off-set the amount of energy used over time.

Totally true, no argument.



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In the "American Solar Challenge" solar powered vehicles are driven across the country, can get up to ~50mph and never use a drop of fuel. Now, I understand that the weight of these vehicles is next to nothing, plus the streamline, no drag design is not conventional to America's current standards, but at least it's a proof of concept that in a few years the technology may be there to make this a practical option.

If you put solar panels on your roof, the power it collects in the time you're not charging is power back to the grid. Just because every watt of energy isn't generated through solar power doesn't mean that you're not offsetting the amount of energy transfered during the charging state.

Here in Los Angeles, if you have solar panels on your roof and you're generating more power than your using, your power meter spins backwards and feeds that energy back to the grid. If you charge 40KW to the car, unplug and do not charge again for a few days or even a week, you can easily have charged back 40KW back to the grid, thus making it possible to have still charged 40KW totally solar powered.

By the way, you seem to be pretty savvy here, have you seen the Sterling Engines? There's a company that is building them right now for So Cal Edison and they're generating enough power from one solar energy dish to power 7 homes (up to 10). Each dish uses a 37 ft mirror to collect solar energy and direct it into a sterling engine... Solar power through thermal energy, not photonic energy. They're getting efficiency as high as 65%. They're more efficient than troff-style solar power.

Imaging if we had 3-4 of these dishes setup per block!!! I can only imagine how cheap and clean electricity would be.

Unfortunately, they're still limited to the amount of solar panels you can place on the vehicle. Technically, it would only worsen by the scale you build at. So for instance, if you built one of those solar racers 15 times larger with exactly scale powered motor and solar panels, it wouldn't work because you're increasing weight without increasing efficiency. But I'm glad the drive is still there. I don't think solar power through panels on the vehicle are the answer, but if you bring together the wireless energy transfer technology (similar to Nicola Tesla's technology) and you post Sterling Energy dishes down the highway (maybe 200-400 meters apart) you can have electric cars that run off solar energy with wireless energy transfer through the road.

Stirling engines (the efficiencies are VERY tasty, I wish they'd more forward much faster with those) and other solar collectors are exactly what I'm on about. The car is just not big enough to collect enough power, but solar stations (distributed or in "farms") could make a big dent in fossil fuel consumption.
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booooo I work in oil and gas buy non fuel efficent cars. I want a 30% pay raise next year too.

^^^ don't worry, I work on systems that use fuel in liters per second!
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^^^ keep up the good work my friend And I will keep working on the systems that get that fule out of the ground for ya.

^^^^ YOUR DAYS ARE NUMBERED!!!
**Evil laugh**

All I need is 10 more years then I can retire.