In many parts of the world there are so-called deregulated electricity markets, where a market operator takes bids for producers and the marginal price then det

In many parts of the world there are so-called deregulated electricity markets, where a market operator takes bids for producers and the marginal price then determines the wholesale price for that time period (usually the period being something between 15 minutes and 1 hour). So yes, if the marginal unit that sets the wholesale price is a low marginal cost producer like wind, solar or nuclear, the wholesale price for that period will be very low. Conversely, if demand is very high and the marginal producer is a peaker gas plant, the price will be very high. This is basically the business model behind grid batteries as well. Buy power and charge the batteries when power is cheap, sell the power when it's expensive. One big problem here is that despite wholesale markets working like this for a long time, customer uptake of electricity contracts with time-varying prices tied to the wholesale price has been very poor. In general it seems most customers rather pay a higher fixed electricity price than check the current price before starting their laundry (or something else that takes a decent amount of power).