Hydrogen cars: A new approach

Okay so everyone's on about hydrogen power, but it is not without it's impracticallities.

"Here's the tank of lies"

No, you can't make a car run on water by electrolysis with the battery of the car that's powered by the engine that's powered by the hydrogen that's powered by... No such thing as free lunch. Stop wasting time and money please.

Toyota Mirai - Courtesy of Toyota

Currently, the Toyota Mirai is pretty much the only mass-market hydrogen car. It's extremely expensive because they opted for an electrical drive system, powered by a fuel cell, which converts hydrogen and oxygen (from the air)
directly into voltage. It has a reasonable 300-mile or so range, but the hydrogen is stored in carbon fiber tanks at 10,000 psi. In the event of a major accident, this would definitely be problematic, and the fueling system isn't really a walk in the park either.

Hydrogen can be burnt in conventional combustion engines, with practically no modification. This is appealing to many automobile manufacturers because they just don't "like" changing anything, ever. It's not as efficient as the Mirai's fuel cell/electric hybrid system, but definitely cheaper.

The clear advantage to hydrogen fuel is that it's renewable. The ONLY resources needed to create it are any source of water, clean or otherwise, and electricity. Alternately, it can be steam-cracked from natural gas, which, in the event of fossil fuel's eminent demise, can be derived of feces from our artificially inflated subsidized corn driven murderous meat industry.

A REAL hydrogen electrolysis rig - http://www.extremetech.com

Either way, a fuel shortage is practically impossible, as demand rises, technology can rise to the challenge and make the process more efficient, eventually reaching an equilibrium. Hydropower also stands out, because it's cheap, easy, and inherently has water nearby. If a significant quantity of our automotive fuel came from solar, we would eventually actually cool down the earth as well, by converting sun heat into our cars moving around instead of warming stuff up.

BUT HOLD ON, these 10,000 PSI storage tanks are conceptually PRETTY FAR OUT, dangerous, and also expensive. IF ONLY there were a more dense way to store hydrogen! Wait, what about water?
Here comes my plan: Water, at no pressure, will be used to store hydrogen on-board the vehicle, and a completely unrelated compound will be used as energy storage, to extract the valuable gas from the water. I recommend: Calcium.

Pure Metallic Calcium

Calcium is generally thought of as some white crunchy garbage, or milk, or bones. In actuality, these are all calcium compounds, and the pure element is a chemically reactive metal, which happens to catalyze the separation of water's elements, becoming calcium hydroxide, and leaving a spare hydrogen for your trouble. Time for math:

Let's say your (inexplicably large) car has a 20 gallon tank (weighing 57kg, or 126 pounds). The energy content of that much gasoline (how much actually potential WORK there is, regardless of how heavy/large/whatever) is just about 2,600 MILLION joules. A joule is just a nice little packet of energy used in chemistry and physics, it's actual definition matters little right now, as I'm just using it as an intermediary.

To get that much energy from hydrogen gas, you would need about 18.5 kilograms of hydrogen. In gaseous form, uncompressed, this quantity of gas would be enormous, about 200 cubic meters, or over 50,000 gallons. However, water, by weight, is about 12% hydrogen, so the same gas stored in water (and extracted by calcium) would be about 88 gallons. BUT WAIT! You can recycle your water, because after your engine burns it, it's exactly the same as it started. Therefor you'd likely only need a few gallons of water at any given time.

Now, the calcium to extract all the hydrogen you'd need for your 2.6 GIGAJOULE energy needs would have to weigh.... 1,630 pounds, or about 4 full-sized drums of the stuff.

Now hold up, recent research indicates the Mirai, Toyota's hydrogen car, only has a 5kg tank of hydrogen. If that's enough for 300 miles, then we could get by with only a barrel and a half!

That's still a no, then. Okay.