LNG is the “new fuel” that will power industry and road transportation well into the 22nd Century. Compact, clean-burning, and one of the most easily extracted of “fossil fuels” (as natural gas), it is a matter of developing the specialized technology to handle the product quickly and safely.
The energy component required to cool and liquify natural gas could be recovered by using waste heat from the burn process to volatilize the LNG, resulting in less waste heat getting out into the environment, a sort of regeneration effect.
Good engineering practice, in fact, should be directed at reclaiming the maximum amount of heat from any industrial process, and putting it to effective use.
Now if a fuel cell that could use methane completely in its process could be developed, that would solve SO many problems.
Get busy, engineers.
Many of the major users of Natural Gas, like commercial power plants, already recover the heat in combined cycle processes. That is why modern combined cycle power turbines are reaching 60% efficiencies.
LNG liquefaction units don't burn Natural Gas, they run refrigeration compressors for most of the energy requirements.
Already done, provided the fuel is pure enough. Using LNG increases the purity to a level sufficient for this use.
http://evworld.com/article.cfm?storyid=1756
http://www.technologyreview.com/news/518516/an-inexpensive-fuel-cell-generator/