Buses are diesel. This tech would not work with them.
The tech that seems to work for buses is natural gas. ortland Maine is converting it fleet over the next two years to CNG.
Steven Scharf
SCSMedia@aol.com
The WWII subs had diesel-electric drives, so I think that it is immaterial what the engine is. Perhaps diesel would be even more economical.
I've heard good things about CNG conversions, not the least being longer engine life. Mechanics were reporting little or no contamination of the engine oil.