As the cost of renewables get close to zero (but never reaching that), the predominant cost will be batteries and transmission. How quickly this occurs is a function of battery cost decline curve and manufacturing capacity ramp.
Coal is already dead based on current trajectories, the body just hasn’t hit the floor yet.
So why is electricity so expensive in places with lots of renewables? A few of these countries have absolutely absurd pricing of electricity per kwh especially compared to places that just burn coal and natural gas, but your sources say it should be significantly cheaper. Even in the US the only cheap electricity we can get is hydroelectric, but even that is not pushed very much due to ecological concerns.
At least in the US, the difference in cost is mostly taxation and fees, along with profit margins due to utility monopolies and price inelasticity. The reason California has more expensive electricity than Texas is almost entirely tied to the monopoly held by PG&E and high taxes and fees.
> Spanish power prices have tumbled in February to a fraction of the price in neighboring France as record wind and solar power generation in Spain has triggered an extreme slump in prices.
> Day-ahead electricity prices for Thursday settled at just $5.20 (4.80 euros) per megawatt-hour (MWh) in Spain, compared to as much as $68.86 (63.59 euros) per MWh for France, according to data compiled by Bloomberg.
France relies mostly on its vast domestic nuclear power generation for most of its electricity needs and is typically a net exporter of electricity to neighboring countries.
> But as Spain’s wind and solar power generation hit new records early this year, Spain has been exporting electricity since February 21, according to grid data cited by Bloomberg. Spain is currently selling electricity even to France.
> Solar and wind power generation in Spain is expected to have hit a record high this month and high output is set to continue into March, per Bloomberg models.
> Cheap power prices have hurt the profits of Spanish utilities but they have been a boon to consumers as retail prices have reflected lower wholesale electricity prices.
In a free market, assuming constant demand, the price is the same as the highest production cost necessary to meet demand. In other words, if 90% of demand can be met by cheap renewables, 10% by expensive natgas and 10% by even more expensive coal, then the price is expensive. The consumer doesn't see the benefit of cheap renewables until they can meet the entire demand.
Obviously electricity isn't anywhere close to a free market, but it sometimes pretends to be one.
Also transmission costs are significantly larger than production costs in most markets.
Most places sensible enough to deploy lots of renewables also tax electricity to encourage efficiency since historically it involved burning nasty polluting coal and/or importing fuels.