I was fortunate enough to recently visit the BMW Welt and Museum in Munich. While we don’t own a BMW, we were told by German friends that it is worth a visit anyway, which we did.
The museum covers the history of motoring (with a BMW slant) and also how BMW sees the future. The exhibit indicated that BMW is speeding considerable R&D on hydrogen based technologies. The displays didn’t really indicate why, only that hydrogen is seen as a fuel of the future.
I was fortunate enough to be able to ask one of the BMW boffins why BMW is spending considerable funds on hydrogen R&D. The response indicated that BMW and some other major car industry manufacturers believe that lithium battery transport technologies will only have a finite life and possibly will be an interim technology until other liquid/gas fuels such as hydrogen replace existing combustion engines. The term used was similar to lithium technology is now while non-carbon fuels will be the future.
I also asked why lithium was considered an interim technology and why lithium battery systems are being pursued by most manufactures (either as plug in or hybrid). It appears that the car industry believes that lithium technologies are reaching their maturity and any advances in the technology will be incremental and potentially smaller than seen in the past. It also appears that lithium battery systems are not the ideal long term solution for the transport industry.
It was also noted that lithium has a challenging future and this appears, reading between the lines, is mainly environmental and cost. The environmental being the damaged caused to the environmental through mining (many lithium mines are in environmentally sensitive location), byproducts of lithium and rare metal earth production for battery manufacture (maybe the recent media about radioactive byproducts from rare earth processing is rattling behind the doors within the industry), capacity for lithium to fully replace conventional technologies (for cars and electrical systems). The cost being when demand increases, the supply of lithium/rare earths will constrain ability to meet supply, thus increasing costs even though the technology costs may reduce (as evidenced currently with lithium batteries becoming cheaper as manufacturing technologies and scale improves).
The response is that hydrogen still has a number of challenges which need to be overcome to make it an alternative fuel, which BMW believes will be the case in the coming decade(s). These challenges include production of hydrogen (high energy input for manufacture for low energy output - energy conversion is low), storage and transport of hydrogen, safe use within the vehicle and sufficient storage capacity for long range) etc. Currently the most effective way to provide hydrogen is from fossil fuels. Research is being explored on how to reduce energy inputs for say hydrogen from water.