Aye, but if the nearest wind farm is 800 miles away, the volts drop alone makes it clear that it can only be secondary on our national grid. Local power is another matter. I have 10KW of solar panels on a building out the back, and as well as selling to the grid, I store power in batteries and occasionally empty them via an inverter back into the house.

The cost of set up was high, as are wind farms on another scale, and the object of the exercise was being green, not making money. That said, the tariff they buy at is unsustainable really, people with solar panels get paid huge amounts.

But like wind farms, my solar panels are either secondary power onto the grid, or local power for me. (Tropical fish and freezers get a nice power cut back up.)

But there's no high efficiency in my calculations. Just a contribution to less fossil fuel long term. And as an ex miner, that's saying something....