Take the case of Tasmania, Australia. Tasmania is generally an energy exporter, and receives 100% of their power via hydro. In 2016, unexpectedly low rainfall led to serious supply issues in the hydro plant powering the island. The solution? The government organized air deliveries of diesel generators to meet the shortfall. Diesel generators are worse than coal.
In mere months, Tasmania's 'green energy revolution' was desecrated by diesel. Decades of progress erased. Green image gone.
As for pumped hydro storage, same issue. If one of your variables is 'we get more than X rainfall', it cannot possibly be described as reliable enough for baseload power.
This is the problem. Green solutions get decimated by reality, and they're dutifully covered up by greenwashing propagandists. Don't look too closely at our diesel generators or gas peaking plants. Don't look at our battery supply chains.
Even nuclear is not a solution, just look at France and Switzerland who had to take down a lot of their nuclear capacity beyond the broken-down NPPs because they lacked cooling water.
A decent renewable power grid has to have a lot of different energy generation paths: hydro, solar, wind, bio-gas, tidal (where possible), geothermal, enough interconnection paths to other regions, storage (battery, pumped hydro, flywheel) and regularly tested backups. The backups may even be fossil, no one has a major issue with that, the key thing is that the backup capacity must never be assumed as a regular operational capacity. And obviously, the generation capacity has to be scaled in a way that assumes a decent set of overproduction as no kind of power generation has an availabilty/capacity factor of 1... if your total consumption is, say, 100 GW, you have to have at least 200-300 GW in generation capacity.
There are quite some ways of providing backup for wind and solar: ordinary hydro power and geothermal energy for base load, pumped storage hydro power, hydrogen conversion and tidal power for peaks. And even gas plants aren't that problematic either - assuming you only need them for peaks instead of, like now, replacing broken-down French NPPs, you can fire them with bio-gas gathered from farm animal dung or bio-waste.
> If you counter with 'what about batteries', the lie by omission shifts from environmental destruction to child slavery. Battery supply chains cannot escape the contaminant that is child slavery.
Of course they can, it is only a matter of money and oversight over governments.