What's In The Pipeline? Hydrogen.
At this link is a 9-page conceptual design paper outlining a prospective hydrogen economy: one based primarily on solar and wind power. The paper's authors are Greg Blencoe of Hydrogen Discoveries, Inc. and Dr. James G. Blencoe of the Oak Ridge National Laboratory. The technical underpinnings of the paper are: 1.) a valveless fueling system that uses magnesium hydride to safely store hydrogen inside fuel cell-powered vehicles; and, 2.) Hydrogen Discoveries' piping system, which was designed to overcome the problem of embrittlement and leakage problems that ordinary steel pipes face. The intention is to overcome the "last mile" problems of safely distributing and dispensing hydrogen fuel, and, in this case, of reclaiming and recycling the Magnesium carrier media for continuous re-use. This is a pre-commercial design concept, and TreeHugger will make sure that any design or risk management comments left here are brought to the authors' attention. We note that although magnesium is abundantly found in serpentine rock, as Mg3Si2O5(OH)4, that serpentine is the California State Rock, and "is found only in areas where oceanic crust is subducted and then pushed up again along fault zones. Worldwide, Serpentine is sporadic in distribution and high in heavy metals, creating rare plant communities on its soils".
One obvious risk management 'driver' is that that serpentine barrens often support rare and/or endangered plant communities. Further, that benefaction and processing of the serpentine rock will produce heavy metal residues; and, it would be essential that these materials be turned into co-products or that magnesium suppliers ensure they are properly disposed of. Both reasons underscore the need to base the system design on a recycling paradigm.
Because both hydrogen and magnesium are highly combustable in the presence of atmospheric oxygen, and because magnesium hydride, unbuffered, is highly reactive with water, the designs will need to deploy an inhibition chemistry, plus fire prevention and fire suppression systems.