Over at Grist, there is an interesting article that looks at the use of renewable energy in US military field operations.
The situation and application for the US military is one where using renewable energy makes a lot of sense. Indeed, for most off-grid locations, it is possible to put together a pretty good business case to use renewable instead of diesel to produce electricty.
Down here on the farm, that situation has long existed for powering electric fences. Today, if I need to pump water for livestock in a remote location, solar or wind is generally the best option.