
Check out the Skybuilt MPS (Mobile Power System). These transportable (not exactly “portable”) power systems fit inside a standard shipping container, which means it can be moved using standard rail, ship, and trucking systems. It can also be dropped by parachute. Power output depends on the configuration, but ranges from 1KW up to 50+ KW. It looks like their basic configuration uses wind and solar power, the higher power systems would probably require fuel-powered (diesel or gas) generators.
From the Skybuilt web site:
The MPS is a complete power station in a standard shipping container. It can be transported by truck, train, ship or plane.
At the site, you can deploy solar panels or wind turbines in just a few hours, for self-generated power. Or, use diesel, propane, natural gas or gasoline-powered generators.
The interior of the MPS can be used for anything—air-conditioned office space, telecommunications, medical center, emergency operations/command center or storage.