Long term? Some kind of storage solution in combination with hydro power and, my preference, natural gas as it burns much cleaner than coal.

Short to mid term? Same as above, only that storage will have to be replaced with something else. Since coal is clearly favoured by the system in Germany coal has to replaced by itself. Coal is just the worst alternative. Unfortunately nuclear is no option in Germany, until storage tech is sufficient it could nicely close the gap.

Natural gas is not a sustainable long-term solution. World emissions need to be brought to zero, in the next five years, in order for us to avoid a climate castrophe.

If we are still positive at the five-year mark, that means zero at, say, the ten-year mark, and negative emissions for many decades.

Natural gas has no place in this long-term.

It's actually very sustainable. Renewable energy production follows a normal distribution. The natural gas plants won't have to produce more than 60% of the electricy during the 10 worst days of the entire year. Therefore a 90%+ reduction in emissions is possible without any storage system at all. Add power2gas technology which will be available over the next decade and it suddenly we are not only carbon neutral, we can also capture it. How are you going to store energy without using gas? Oh and did I mention that 10GW worth of natural gas plants costs less than a 1 GW nuclear power plant? Therefore not running natural gas plants most of the year is cost effective.

Well, it has a place in the energy mix because modern gas power plants are incredibly fast to ramp up. So they are perfect to quickly stabilize the grid. As a base supplier not so much.

"Natural gas has no place in this long-term."

Carbon sequestration is possibly a viable solution. There seem to be solutions in trial (there are numerous questions around it), and even with added costs of capture, it's considerably cheaper and more reliable than other form of energy - moreover, we have it in abundance.

Natural Gas is as viable for the horizon of our future we're able to predict.

In 100 years, every dimension of our tech will have changed so much it's hard to predict. Maybe we solve the nuclear wast problem. Maybe we get fusion. Maybe we have uber cheap solar. Maybe we have dirty easy sequestration. Maybe we have alternatives.

We have already solved the nuclear waste problem. The issue is that nobody wants to bury it in their backyard, so to speak. Waste containers are incredibly safe and secure, and modern fuel waste is much safer than gen 1 fuel waste. People like feel-good shiny solar panels and wind turbines over concrete near-zero emission solutions.

We haven't solved the 'waste problem'.

1) Long term storage has some existential risks. Over very long time horizons, these risks become real.

2) Transportation, processing and storage: all of this operational stuff is totally ripe for accidents.

It doesn't. The impact of radiation is a rise in cancer rates which even if they substantially shorten lifetimes aren't X risk.

Your answer is basically 'radiation causes rise in cancer which can substantially reduce lifetimes is not a risk'.

I don't see how that's reasonable, I suggest you might have typed something incorrectly.

There are still quite a number of risks inherent in the Nuclear process that require only a few operational failures for disaster.

If very smart countries and operationally efficient countries like Japan screw up the risks, then anyone can. And that there were mitigating circumstances does not change the fact that Japan still had great governance and scientists and persisted with either risky models or a failure to measure the risk.

Basically, we'd need to suck the risk out of every part of the process in order for it to work well.

I think it's possible.

What's the existential risk? The absolute worst case that I can imagine is that all the waste somehow ends up in the ground water. That would be extremely bad, but localized to the area where the waste is stored.

Existential is as you mentioned: ground water pollution of the entire NE seaboard. Terrorist dirty bomb in NYC that affects 30 million people as the weather carries particles etc.

inverse square law and lack of any volume of any highly active source makes dirty bombs a nonissue. they are scarier than they are effective.

Again, waste storage is incredibly secure and safe. It wouldn't leech into the water. Nuclear subs have sank into the ocean, and, surprise, there wasn't a global disaster.

The concept of `baseload' is entirely a creation of the system of extremely large thermal plants that are essentially a path-dependent outcome of the electric grid's development. There is no intrinsic usefulness in the concept.

In other words it would be good to stop acting as though the only possible grid is one that looks exactly like the one that was developed in the early 1900's. There are many other arrangements of generation resources and economic structures to pay for them than the existing grid. That is what renewables are moving toward.

well we certaintly aren't moving towards that in Germany so I wonder where they actually are and what that looks like in reality. If everyone else is also just going to burn more coal than ever before all of this is nothing but a very expensive step backwards.

What makes you say that? Take a look at the summary in another comment: https://news.ycombinator.com/item?id=19913933

That looks like progress to me. Why do you say "everyone else is just going to burn more coal?"

They will power the infrastructure of the new Nord Stream 2 pipeline build against EU interests, obviously. That and strip mined Hambach forest.