Hi,
What you want is a thermopile not a thermocouple. A thermopile is a bunch of thermocouples connected together in series or series parallel. They are used on space craft to generate electricity from onboard thermal reactions.
But the problem is, just like thermocouples they do not work on the principle of temperature, they work on temperature differential. For example, a wire that is heated at one end and kept cool at the other end develops a voltage across it's length, but if the wire is heated uniformly from end to end it does not generate a voltage.
What this means is that if you did use a thermopile you'd have to find a way to have one end (or side) heated more than the other. For example, if you had a box with two ports in it one end of the thermopile could be exposed to the sun but not the wind while the other end could be kept damp with water and exposed to the wind but not the sun. So one end would be cooler than the other at all times.
The only trouble is it sounds like you are looking for MUCH more energy than you can get from these things without resorting to some sort of nuclear reaction, so i have a feeling this wont work anyway.
Your best bet here is solar energy using solar panels to generate the current to charge batteries and draw the power from the batteries when needed. Depending on the power needed however this can get expensive, so it depends how bad you really need it...life support or just hobby electronics