In fact, wind and solar often bid negative amounts to sell power.
For those confused by this, the way a utility buys power is they take bids from powerplants, and then "fill their bucket" with the cheapest options, the most expensive, cheapest option is what everyone gets paid. So if you can compete in a market with coal and coal is 8 cents/kwh, and you have zero operational costs, you can bid negative values to always be in the bucket and be compensated 8 cents/kwh.
For those confused by this, the way a utility buys power is they take bids from powerplants, and then "fill their bucket" with the cheapest options, the most expensive, cheapest option is what everyone gets paid. So if you can compete in a market with coal and coal is 8 cents/kwh, and you have zero operational costs, you can bid negative values to always be in the bucket and be compensated 8 cents/kwh.