857
It's still not earning you money to spend electricity because you still have to pay the transfer fee which is around 6 cents / kWh but it's pretty damn cheap nevertheless, mostly because of the excess in wind energy.
Last winter because of a mistake it dropped down to negative 50 cents / kWh for few hours, averaging negative 20 cents for the entire day. People were literally earning money by spending electricity. Some were running electric heaters outside in the middle of the winter.
You sell it to places with different weather conditions (or as noted, to places with storage capacity) - and if everyone in the grid becomes as successful as Finland, well "good job, everyone!"
The "places with different weather conditions" are across the equator. Everyone in the northern hemisphere has summer at the same time. The best we can do with interconnects up here is shift the problem around by a couple hours.
Now, if we convert that excess power into cryogenic hydrogen, load it aboard a tanker, and drive that tanker to the end of the earth currently experiencing winter, they can then burn it in gas turbine generators.
Hell, we can put such generators on ships and move them back and forth every 6 months.