I think we sell power mostly to alleviate excess supply during low demand periods since most of our generation is relatively stable. Another way to alleviate excess supply in low demand periods, if you can’t sell it to your neighbours, is to shift demand from peak periods by… making peak more expensive.

And a third way is to make the cost of electricity during low demand periods negative, to incentivize excess electricity use (and enterprising individuals with storage capacity to charge up so it can be discharged during peak).