Can I use wind power off grid? Theoretically yes, but in practice no.
To be able to go ‘off grid’ and supply yourself with electricity is very complicated because you have to balance the supply of electricity from the wind turbine, which varies with wind speed, with the loads on your site which also vary as things are turned on and off.
This can be done with very small (i.e. circa 10 kW) wind turbines by using batteries to store excess energy from the wind turbine which can then be used later to help meet higher energy demands that are more than the wind turbine can supply.
Although in principle this could work for a larger wind turbine, the size of the batteries required would be prohibitively expensive, and no large wind turbine manufacturer would sell you a turbine for standalone operation because of the risk of it all going wrong and their reputation being damaged. Hence medium and large wind turbines must be grid connected, and if there is a power cut they will automatically shut down and only restart once the power is restored.
Are you considering a wind turbine project?
The first step to develop any wind power site is to conduct a full Wind Turbine Feasibility Study.