My recently study on ANG, in 16 bar ratio or lpg tank max pressure and "standart" activated carbon show for 1 to 50 storage ratio to methane ratio. Not so fancy as stated with special activated carbon - 1 to 170 or more, but sufficient to beat EV in range and efficiency.
Later, i will post best schoolar articles, found so far.
One of the best, general testing without fancy tech or know-how.
http://www.anl.gov/PCS/acsfuel/prepr...09-65_0132.pdf
http://www.anl.gov/PCS/acsfuel/prepr...03-96_0246.pdf