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.
That is surprisingly expensive, it's more than here (Cambodia), which is notoriously high for the region at around 20c.
If you want people to use less energy this is the only way
Alternative: Create more energy, preferably renewable. Penalize heavy users only (raise costs). Incentivize (lower costs) those using renewables like solar panels. Raising costs for all is the laziest way.
Except people are going to cheat like they always do