[MisterMe]

After Alan Shepherd's first suborbital flight in 1962, President Kennedy announced a national goal of sending a man to the Moon and returning him safely to Earth by 1970. Despite the two-year delay due to the Apollo 1 launch pad fire, Neil Armstrong stepped on the Moon on July 20, 1969. That was 4.5 months ahead of schedule. If NASA had not been forced to redesign the Apollo capsule, then we could have done the deed at least a year earlier.

Most of the technology to put a man on the Moon was developed during the seven years following President Kennedy's speech. OTOH, the biggest hurdle facing hydrogen is mass storage. That's not a huge problem. Hydrogen's other challenges are mainly tweaks to existing technologies. It is nowhere near as daunting a challenge as putting a man on the Moon.

Originally Posted by edsuski

Can someone help me understand the Hydrogen Fuel Cell model?

Hydrogen is not a fuel. It is an energy storage mechanism somewhat like batteries and tanks of compressed air. Unlike batteries, hydrogen storage does not lose capacity over time.

Originally Posted by edsuski

By most estimates - the needed infrastructure is eight to ten years away (converting a significant number of today's gas stations into Hydrogen refueling stations).

Whose estimates? There was a time when service stations sold two or three grades of leaded gasoline. We have deleted lead, added diesel to passenger car pump stations, and added various formulations of MBTE, and now blends of ethanol. Do you think that any of these changes required eight years?

Hydrogen generation requires water, which every service station already has; electricity, which every service station already has; an electrolysis station; hydrogen compressors; and hydrogen storage tanks.

Originally Posted by edsuski

The energy required to produce H2, compress, cool and store it would result in more driving range if the energy were simply used to charge a Li Ion battery (such as those used in the Tesla and Volt). The basic physics does not seem to make sense (?).

As I said above, batteries lose capacity over time. Hydrogen tanks do not. As for energy use, all energy systems suffer losses. It is called the "Second Law of Thermodynamics." Look it up.

Where do you get the notion that a Li+ rechargeable battery would result in greater driving range than hydrogen storage tank? To be a general replacement for gasoline, the vehicle should get at least 300 miles (500 km) on a fuel-up. Lithium batteries are much less massive than lead batteries, but they are still batteries and are still massive. The only way to increase the range of a battery is to increase its mass. OTOH, if you use compressed hydrogen, then you increase the range by increasing the amount of hydrogen. Most of the mass is in the storage tank. Increase the amount of hydrogen by increasing its pressure. The mass goes up only slightly. If you want a higher capacity tank, then the increase in mass scales slower than the increase in capacity.

Originally Posted by edsuski

I fear that Hydrogen fuel cells are simply a diversion from the real and technically feasible PHEV's. In many ways it looks like gasoline (it would likely be delivered by trucks and stored in tanks and distributed through hydrogen "gas" pumps etc.) so it would re-use the current business model of gasoline stations but, you would still need to visit the station to refuel.

You make a lot of assumptions that simply are not true. First off, there is no conflict between plug-in hybrids (PHEVs) and hydrogen. Hydrogen does not imply fuel cell. It can be burned in an internal combustion engine (ICE) much like natural or compressed petroleum gas. BMW's hydrogen-powered 7 series uses a V-8. Like the BMW, hydrogen can be used to power the chemical engine of a hybrid. As I have stated above, hydrogen does not have to be transported by large trucks. It can be generated by the filling station on site.

Although hydrogen can be used in ICEs, it is most efficient in fuel cells. Try as I might, I do not see hybrids as anything other than a transition technology. They have the mass of an ICE, the mass of electric drive motors, the mass of storage batteries, and the complex electrical and mechanical systems required to manage their two drive systems. With added mass comes added inefficiencies.

Originally Posted by edsuski

The needed infrastructure to refuel PHEV's is essentially 100% deployed to virtually every home in America. For longer trips you would have to rely on some other type of fuel such as gasoline or E85 etc. but, the infrastructure for, at least gasoline, already exists. And remember – 78% of America commutes less than 40 miles per day so the consumption of gasoline “could” be reduced to far below what we can supply domestically when enough PHEV’s were in service.

The PHEV is at its best if the owner has a solar-powered recharging station. However, solar power can also be used to generate the hydrogen required by a hydrogen-powered car. Of course, a hydrogen generator, a compressor, and a storage tank will be required. Do you expect that the costs of these home additions will be out of line with home additions of the past such as central air conditioning?

Originally Posted by edsuski

... They would require more energy per mile than PHEV's and a HUGE investments in infrastructure to make them feasible. ... Help me out – why use Hydrogen fuel cells?

I just don't see the requirement for your HUGE investments in infrastructure. We won't build the infrastructure by the end of the week, but I believe that it can be done within five years. That would be about the same time that it would have taken us to get to the Moon if the Apollo 1 capsule had never burned.