is it realistic to think i could build a windmill and use it as an energy source in newfoundland, canada?

Question

we have a lot of strong wind here.

Answer 1

I'm sure you could. But the cost of designing, building, and maintaining it, as well as the support structure required (such as storage for battery, inverter for power conversion, controllers, etc) will be far greater than just purchasing the same amount of energy from the commercial source. (ie. power company)

Also, don't forget, the battery and its upkeep and eventual disposal and renewal aren't environmentally friendly either, if that is your motivation.