What's the difference between grid-off and grid tie in the inverter of a windmill?

Question

I'm considering buying a windmill (wind engine turbine) and when it comes to the specs of the thing, I'm lost at the level of its inverter (also controller) where 2 options are presented.

It's either a grid-off, or a grid-tie... I personally have no idea what they mean so if someone can provide me with explanations and answers, I would be very grateful.

Thanks for advance.

PS: Stupid answers will be reported!

Answer 1

It has to do with your house wiring and whether you have 1 small battery or lots of large batteries.

If the power company allows it, your best option is to connect your turbine to the power grid, so when you have excess power you can sell it to the power company, and when the wind dies, you can buy power from them. This of course requires their permission (and not all allow it), and they will either supply or approve the equipment to connect your DC power to the grid. This includes a special inverter to generate AC power that can be (it must be) phase locked to the power frequency.

If you can't or don't want to do that, then you need lots of batteries to supply power when the wind dies, a charge controller for the batteries, and an inverter. What kind of controller and inverter is up to you. I'd recommend a "pure" sine wave type.

You will also need wiring to connect the inverter output to the various appliances that you have.

You could use the existing house wiring, but then you will need a large switch to switch all the wiring between utility power and wind power, so you can switch back when the wind has been gone for a long time and your batteries are dead.

That's it in a nutshell. contact me if you need more info.

PS, average utilization for a wind turbine is 30%, which means it is stationary 70% of the time. That varies by location, the height of your tower, etc.

But it means you need to get a turbine at least 4 times your average current load, to 1. cover the times of no wind, 2, so you have excess power to charge batteries or sell to the utility, and 3 to cover future expansion.

If you do use batteries, you will soon find that you need dozens of large and expensive batteries, if not hundreds, to cover a full day with no wind. Which is why selling power back to the utility is best.