This paper identifies the cost of power consumed by a gas or diesel engine as $500 per HP over a 10,000 hour life.
In addition, it shows how the rate of increase of fuel costs is affecting the end user's purchasing decisions.
It also contains some general ideas on how mobile equipment can be designed to be more energy efficient.
This paper should be of value to both the designers and the sales/marketing people at the mobile O.E.M.'s.