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Comment by _acme | Hacker News Reader

You do understand that electricity is still needed to charge these cars, right, and that a lot of that energy comes from oil (or worse, coal).

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It might be a minor improvement, but it's still an improvement.

Oil burned in a plant is higher efficiency than when burned in individual, smaller-scale engines.

Stated as a corollary: imagine how dirty having per-car coal furnaces would be...

Name one "oil" fired power plant?

Coal yes, nat gas sure, hyrdo (which is where alot of MI power comes from) you bet yea but I have not seen a oil powered electric plant.

further even is such a thing does exist, generating electricity has a much high efficiency then the IC engine which is by for one of the least efficient systems there is

If customer demand for electricity grows high enough, there's no reason oil-fired electrical plants won't arise on a large scale. Efficiency issues can be addressed much better when implemented on a scale much larger than a car engine.

https://en.wikipedia.org/wiki/List_of_power_stations_in_Mich...

Also, while Michigan has a lot of hydroelectric stations, they don't account for more than a few percent of the state's electricity.

We can call it (Tesla) incremental departure from oil. Down the line, we might be able to charge tesla under lot lesser time than what it takes today. May be we will have solar tesla or self charging tesla.

At least, these constant rip-offs of every n month this fluid change will go away.

When I was a kid, I saw the movie Logans Run (1970s). They made it to washington DC and found a car. They didn't know what it was, but they shined a light on it, and it started to activate and so they conclduded "maybe this thing is powered by the sun"... and it was.

Well, it's been 40 years since that movie was made. Alas, a solar powered car may still be many years off... but the elegance of it is certainly extremely appealing.

One problem: I love the Tesla's expansive sunroof. Would want solar collectors that are at least semi-transparent to light.

There just isn't enough surface area. A Model S has a roof area of around 9m^2. The sun provides about 1000W/m^2 on a clear day at high noon when directly overhead, so with 100% efficient solar cells on a perfect day, you'd get around 9kW of electricity. A Model S goes about 4 miles per kWh when it's doing well, so in this ideal situation you'd top out at around 36MPH. In the real world, the sun isn't directly overhead, and real solar cells have more like 20% efficiency, so cut that number down by a factor of ten or more.

The best way to build a solar-powered car would be to have a battery-powered car that gets recharged from solar energy. Basically, a Model S and a home solar generating system.

That illustrates the advantage of electric cars, even if the electricity is currently generated by fossil fuels.

I recently ballparked the cost of a home solar charger for my Leaf EV. Came out around half the price of the car ... not cheap, but feasible for someone serious about it.

I do have a propane-powered electrical generator for emergency/backup home power. Some day I'll try charging the Leaf with it.

Have you ever worked out your approximate cost per kWh for the generator? I imagine it's painful compared to what you get from the power company, but I'd be curious to know just how painful.

About $1.23/kWh.

Ad verbiage for the allegedly 3250 running watts generator states "engine run time of 10 hours at 50% on a common 20Lb (gas grill type) cylinder". So that's under $2 for 1.625kWh, which is roughly the power draw for recharging the Nissan Leaf in question, which takes 20 hours - costing upwards of $40. More to your point, that's about $1.23/kWh. Not cheap, but a 10x markup is appropriate and acceptable for emergency needs.

Thanks. That sounds pretty reasonable for a generator, considering.

You probably mean 0.9m^2. 9m^2 is a decent size bedroom.

I shouldn't have said "roof," I meant the whole vertical-facing area of the car.

Unfortunately that was only science fiction. I don't think the sunlight that lands on a car would be sufficient by itself to charge the system to any acceptable level.

My back-of-the-envelope calculation, if covering an entire car with solar panels... Assumptions: car width is 5 ft, hood is 5 ft, roof is 3 ft, and trunk is 4 ft makes 60 square feet for the whole car. (Note, this isn't the dimensions from a Tesla, but from the older cars that I remember). High output solar panels are 15 watts per sq ft. So 900 watts output max (lets round it off to 1 kilowatt to make the math easy).

Now taking the rated specs from a Model S, a 60 kWh battery gets you 200 miles. So .3 kWh per mile. Therefore, leaving you car to recharge in the sun for 8 hours while you are at work, will get you home if you live within 25 miles. Assuming maximum efficiency of course. Note, that you can't put 60 sq feet of solar panels on the Model S, due to the long slope of the front and back windows, and redesigning it so that it has the non-window surface areas of my old 85 Chevy would make it less aerodynamic. But this gives you a good upper bound if I did my math right.

or better, nuclear

Nuclear's only an option if we have breeder reactors that can reprocess all the waste into non-radioactive outputs. In the meantime you still have all that radioactive plumbing being replaced that needs to be handled, and I really don't want that being buried in my watershed, food bowl, or anywhere that might end up being a watershed or food bowl for people elsewhere in space and time.

So find a way to build a nuclear reactor with non-radioactive outputs, built with materials that do not corrode due to the radiation, and we have a deal!

Oh, and the final result needs to have a higher EROEI than current state-of-the-art solar panels.

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