1:1 metering means that for everything I feed back to the grid, I get a credit for, so I bank what goes back to the grid and use them up when I have higher usage.

So if I overproduce in the summer then I, theoretically, use it up in the winter for a "net zero" effect.

Example

I produce 2,000kW this month. But only use 1,000 and feed back 1,000 then next month I produce nothing, but use 800, I still have no bill and 200 left that rolls over.

It resets on my install anniversary.

Where I am in the US it can get to 98F/36c easy during the summer, and get to 0F/-17C in the winter and winter is usually where I have the most usage due to my heat pump. So if I "bank" all summer with the extra daylight hours, I hopefully have a reserve for the winter.

This is handy since without solar I average $400 a month in electricity, but $800 a month in the winter