Will the cost of all these transmission lines and maintaining them be significant?
Given we get bushfire where half the country is on fire will that affect lines and energy security?
These offshore windmill cables now seem to be at risk of submarine attack.
I'm just not convinced it's reliable or secure. At home solar and battery yes.
It all comes down to numbers on both the technical side and the economics. Noting that 100% reliability isn't possible - we can get very close but that's all, it's never 100% there's always some chance of failure no matter what technology is used.
Fundamentally it's very similar to the operations of casinos, agriculture, aviation or the stock market. High reliability is possible but bottom line is the probability of disaster is never truly zero.
Casinos can go broke. The model of probability can indeed produce a string of heavy losses and bankrupt the casino. It's not impossible.
Agriculture can fail. Just needs enough floods, droughts, locust plagues and so on and humans starve. The chance that it happens is not zero indeed it's somewhat alarming to realise no proper modelling has been done, that human food supply is actually being left to chance.
Put your money into a portfolio of blue chip stocks and the chance that they all go to zero is extremely small but it's not zero, it is indeed possible that every large cap stock goes bust - very unlikely, but not totally impossible. Putting your money in the bank comes with the same risk, failure is not impossible.
Get on a plane and no matter how well it was designed and built, no matter how well trained the pilots are and how good the maintenance, there's a chance you'll never be alive on solid ground again. Disaster isn't impossible.
And so on. 100% reliability can't be guaranteed but we can do greater than 99.95% pretty easily.
From there it's a matter of data collection and calculation to determine the reliability of any given arrangement, or alternatively to determine what's required to achieve a high level of reliability in supplying any given load.
Done properly it's not about one technology being superior to another. They all can and will fail that's a given, all that varies is the nature and probability of that failure but none are bulletproof.
Pick any example of a failed electrical system, anywhere in the world, and almost always it comes down to one of these:
1. The original design or construction of equipment was inadequate either due to lack of knowledge at the time or due to recklessness.
Eg transmission lines in Australia built without an understanding of convective downbursts (a meteorological phenomenon not an electrical one) are an example of inadequate knowledge at the time.
2. Operation was reckless and/or maintenance was lacking.
Eg Callide C in Queensland - that's an almost incomprehensible level of incompetence.
3. Outright corruption, fraud, theft, sabotage etc.
Eg South Africa.
4. Geopolitics - someone intentionally caused it to fail, eg cut the fuel supply off.
Eg Russia versus the EU or prior to that the 1973-74 and 1979 oil crises.
5.
The system with all its components was inadequate for the load placed upon it
In developed countries that last one tends to be the biggest risk and is often wrongly perceived as a failure of a specific technology. For example a coal plant fails during summer and the media headlines scream "coal fails in the heat", failing to grasp that firstly heat didn't cause the failure and secondly that the real problem isn't the failure of an individual generating unit but rather, it's having a system that can't cope with an entirely foreseeable event without leaving consumers in the dark.
That it worked so long as the weather was mild and demand was lower and that there were days when all coal plant worked perfectly is somewhat meaningless. Anyone competent knows that hot and cold weather occurs and that generation failures will occur hence reserve plant is required. There are proper ways to calculate that but as a simplification in layman's terms, take the maximum demand that's reached under whatever circumstance drives it (eg heatwaves) and add 20% and that'll be very close to correct. And yes, that ~20% most certainly is required - it's because generation outages are certain to occur and are in no way surprising.
Same with renewable technologies. Failures occur because the overall system wasn't up to scratch, it was inadequate for the load placed upon it and that being so it was inevitably going to run out of stored energy at some point. That it worked when demand was modest and the weather was favourable doesn't change this, if it's inadequately designed or operated then at some point it will fail that's a given.
Personally I'd be more than comfortable with any system that:
Is properly designed to an acknowledged reliability criteria based on system load at least equal to actual load.
Is operated to strict technical criteria based on the engineering design.
Is not subject to unmitigated geopolitical risk (eg fuel imports).
Has a clearly identified expansion path, specific projects, to be built if and when required. Noting this may evolve over time if technology changes.
Subject to periodic technical audit of key assets and procedures to mitigate the risk of recklessness (eg the Callide C scenario) and subject to routine testing of backup systems and procedures.
Nuclear or renewable?
Well I haven't answered that for a very good reason. The only rational reason to prefer one or the other is if you don't think we're capable of following rules for design and operation and are thus looking for something that's foolproof. From there well it has to be said that nuclear reactors, tanks full of LNG, big dams or large wind turbines all have something in common - they're a really bad idea in the hands of anyone incompetent or reckless, they're not an even slightly good workaround to that problem.
What really needs to happen is for politics to step back and shift the focus to maths and science.
Because we used to be really good at this stuff in Australia. All up Australia historically achieved quite a few world firsts with electricity and things relating to it so it's really quite ridiculous that we're struggling now. Go back 30 years and we easily be the US on price, today they beat us by a considerable margin. Etc. It's not that we can't do it, just that we've become distracted by two basic problems:
1. Engineering and economics has given way to politics and ideology as the basis for decision making.
2. The industry focus has shifted from cost minimisation to revenue maximisation.
That's it really. Fix those two points and the rest just goes away.