Another problem with hydrogen is the lack of infrastructure to transport it to where it will need to be distributed.

There is technology in the works to use CO2 to convert Hydrogen gas into hydrocarbon gas, which could be transported using existing pipelines to people's homes. Anybody with a gas furnace or oven could then re-fuel their vehicles at home from the same source. The bonus of this is that it could be carbon negative, removing greenhouse gases while providing a usable fuel.

I say if an inventor comes up with a super capacitor that meets the "battery package" requirements, she ought to get the $300 million.

The problem with hydrogen is that thermodynamics is completely against it. Compressing the hydrogen to such a degree that it represents a useful vehicle fuel requires a tremendous energy input, making hydrogen an uneconomic way of fueling your vehicle. By contrast, the theoretical power density of batteries is quite high.

Theoretically you can regain that energy when you decompress it, so that the only net loss is due to the inefficiencies of your pump. Still, the main heat loss is in the creation of the hydrogen in the first place, since it's not readily available in gaseous form.

Batteries have the same problem, it takes more energy to charge a battery that is will discharge, plus you have breakdown of the chemicals in the battery itself. Super-capacitors may be a more efficient alternative.

Is he serious about solving the problem? Seems like a half-baked stunt to exclude something so obvious. Sad, too, because I want to like him.

The problem with this proposal is that the inventor of such a battery would stand to gain much, much more than $300 million just from marketing the device. The financial incentive for battery development is clearly there already. So what does the "prize" add?

The prize pays when you have a prototype, the market only pays when you have demand and production. It's the difference between getting $300k after 1 year, or $3m after 5 years. Sure the $3m over 5 years is more money, but investors would like the possibility of return (or at least reduction in debt) after only 1 year.

Take the Ansari X prize that gave us the first privately built space vehicle. It cost way more to develop than the prize paid out, and stands to gain way more in revenue from the technology in the future, but it took the competition for the prize money to spur the initial investment.

Even if the battery is developed, there is still the risk that it won't sell for one reason or another and recovering a big chunk of the development money is an incentive alone.

In addition, when you're trying to direct peoples' innovation and/or research this far ahead, a prize seems to bring people out of the woodwork to put forward their ideas.