We'll most likely see off-peak or dispatchable-demand energy prices become effectively negligible due to cheap intermittent sources, but the price for reliable 24/7 supply will if anything trend higher. Storage is not enough to bridge the gap in all cases, so you need either very expensive peaker plants or less expensive nuclear to provide a reliable baseload supply for those critical uses.

Demand is rising very fast compared to supply, I don't think that will happen.

Energy is like RAM or clockspeed: you can't have enough of it.

> decreasing (nominal) energy prices in the future

Hasn't happened ever before, not sure why this time it would be different.