schroedingershat

Four points:

The profile of other is short spikes 5-100 hours a few times a year.

1 year of delay is equivalent to 20 years of exclusively using fossil fuels for "other".

It's not even obvious that adding nuclear reactors would reduce this because they're so geographically and temporally inflexible. France has 63GW of nuclear capacity, <45GW of average load and 61GW of winter peak load with vast amounts of storage available via interconnect to hydro countries. They still use 5% gas on top of the rest of the "other" (which is about 10-25GW).

5% of other from gas adds about 20g CO2e/kg per kWh to the total. Less than the margin between different uranium sources.

Running 40% of the capacity 10% of the time puts your nuclear energy in the realm of $1-3/kWh. The list of ways of generating or storing 6% of your energy for <$1/kWh is basically endless.

That's about 4-8TW of capacity worldwide. 1kg of uranium is good for fuelling about 750W of reactor on a 6 year fuel cycle. Loading those reactors would require digging up all of the known and assumed-to-exist uranium immediately.

Nuclear is an irrelevant distraction being pushed by those who know it will not work. You only have to glance at the policy history or donor base of the politicians pushing for it in Sweden, Canada, Australia, UK, Poland, etc etc or the media channels pushing it to see how obvious it is that it's fossil fuel propaganda.

It is obviously obviously true that it's a non-solution. It fails on every single metric. All of the talking points about alleged advantages are the opposite of the truth without exception.

"Baseload generator" isn't a useful concept. And grid reliability (which is a useful concept) is thought about. It just doesn't fit into a soundbite like winddon'tblowsundon'tshine.

Here's an example of a full plan https://aemo.com.au/en/energy-systems/major-publications/integrated-system-plan-isp/2022-integrated-system-plan-isp

Or a simpler analysis on the same grid: https://reneweconomy.com.au/a-near-100pct-renewable-grid-for-australia-is-feasible-and-affordable-with-just-a-few-hours-of-storage/

For reference, 5kWh home batteries currently retail for about $1300 so this would add <10% to the capital cost compared to recent nuclear projects. Pumped hydro is about half the price per capacity, but a bit more per watt. The former is dropping at 10-30% per year, so by the time a nuclear plant is finished, storage cost would be negligible.

Here's a broad overview of a slightly simplified model https://www.nature.com/articles/s41467-021-26355-z demonstrating similar is possible everywhere.

Even in the counterfactual case where the ~5% of "other" generation is only possible with fossil fuel, focusing on it is incredibly myopic because the resources spent on that 1% of global emissions could instead be used for the other 70% which isn't from electricity and has different reliability constraints.

This only works if you pretend the organic farm depletes soil carbon and emits NO2 at the same rate as the fertilizer farm, fugitive methane doesn't exist (anything with fossil gas in its upstream suplly chain has its emissions under-reported by a factor of about 3), and that the vast tracts of land poisoned and degraded by fracking are completely fine.

You also have to cherry pick small scale lifestyle blocks for your analysis and assume that the land previously degraded by industrial agriculture could be used further at the same yield.

(i edited above accidentally hit enter too soon)

Long duration storage isn't used year round. Charge with wind in autumn->don't burn stuff during jan/dec or dunkelflaute isn't an edge case, it's about 10% of all energy and the only real use case where renewables absolutely need LDES.

Yes in a scenario, which you are in a cold climate which it is always cold outside. Then yes, thermal energy storage would be an extremely efficient option.

I'm not sure I follow why this is an edge case. Space heating indoor areas with surplus wind energy stored in september-november when it peaks is the absolute largest block of inflexible demand for >100 hour storage. With PCM or suitable risk management of high temp. sensible heat it represents the plurality of potential storage demand.

Batteries may still win due to flexibility and prevalence of solar, but I can't think of a better use case for thermal storage.

It's also probably the oldest storage tech by about 8000-100,000 years

well no storage can be 100% efficient but you are correct that thermal storage is very efficient if you want a thermal gradient to leverage for heating (cooling as well)

If I have a room, and I want it hotter than outside now, and hotter than outside later, then putting an insulated box in the room and heating the stuff inside the box, then adjusting the lid to heat the room at the rate I want is 100% efficient. There is no loss eitber in practice or in principle nor any mechanism for one. This is true so long as I want all of the heat, even if I stored high grade heat and run it through a heat engine to make work before heating the room with low grade heat (in which case I might even call it a coefficient of performance of 1.3 or "130%"). I will never match the COP of a similarly engineered heat pump if all I want is low grade though, so in this sense "efficiency" is <100%.

Carnot batteries (where I have a box but don't want heat now or later but do want work) are quite inefficient (10-50% + a time based loss that only becomes negligible at the GWh scale) , or thermal storage in unheated environments (time based loss) are much less efficient.

A separate heat and cold store from a heat pump feeding a combined heat and power generator is another variation (where a COP might come close to or exceed 1).

F=ma is a bit of a thought terminating cliche (as well as being poor communication and missing a term). E=Fh=mgh. As per my link there are plenty of suitable hills and gullies over about 90% of where people live. A human made structure to lift will always be questionable.

I guess it depends on what you mean by rare long duration events but yes one can imagine a situation where the burning of hydrogen is justified on an energy needs basis

A handful of hours of storage (3-12) can pretty trivially meet loads 90-99% of the time. The remainder tends to be events that are 50-200 hours. Pumped hydro and non-round-trip storage (such as delaying EV charging, overprovisioning an industrial drying step and running it when electricity is cheap, direct ammonia electrolysis for fertiliser during high production times, or storing domestic heat in a pond for winter) can cover most of these.

For the remainder (odd once-in-a-decade weather events or major infrastructure failures) the duration is even longer (100-1000 hours). One strategy is to just keep fossil gas generators around because 100 million tonnes of CO2 emitted and 1100 tonnes of CO2 removed that month may be easier than 0 and 1000. Another is to make something with electricity to burn (which could involve an electrolyser and could involve hydrogen gas storage but does not have to).

Spain and china managed just fine. Rail costs way less than 20 lane highways.

Cool. Let's do a mix of regenerative and industrial plant based agriculture then. Animals contribute 70% of the emissions whilst providing <20% of the nutrients.

We can also end fossil-fuel fed energy crops while we're at it.

DAC works? Great! Now every kg of carbon dug up can come with proof of another kg being sequestered permanently in stable solid or liquid firm starting immediately.

You're just sharing propaganda. Those 100 companies cannot pollute without your money and consent. If everyone gets out of the car it no longer matters that the footpath is gone, you can walk on the street. The beef industry can't use 50% of the land and emit half the methane if noone buys red meat.

Chevron and Tyson foods are responsible and you are responsible. They will never step up and they will always use the power you give them to do evil, withhold it and show those around you that it can be done. The message you are spreading is both disempowering and deflecting blame.

There's a difference between those in control of the system assigning blame to the peasants to avoid consequence, and owning your own share of responsobility.

If you drive or otherwise consume oil and you don't have to, you are at fault -- but so is Shell for digging it up and destroying the tram. You are also at fault for giving them money, but so is Chevron for using that money to bribe the government.

Owning your personal contribution, minimizing it, and more importantly, showing others how is praxis.

Buying oil is a form of direct action helping the fossil fuel industry. So is driving because you make being outside a car just a little more unpleasant and dangerous. Buying a big car is even worse.

The only myth worse than your carbon footprint being the only thing that matters, is the idea it doesn't matter and some nebulous "them" needs to fix it.

It's not a problem insofar as it costs more than what we are doing now.

It may not happen because renewables and batteries are on such aggressive cost curves that it may be better to just store energy locally or produce more (and thus generate flexible high energy cost economic activity on top of the current energy demand that can happen whenever).

Transmission and distribution currently costs in the ballpark of 3-7c/kWh. Longer distances will drive this up. Overnight-scale storage will drive it down (allowing it to run 24 hours a day at x watts rather than 4 hours at 6x watts).

Solar energy is 1-6c/kWh. Overnight-scale battery is 2-7c/kWh. If you can rearrange your manufacturing so you do the energy intensive bit on a cheap machine on a sunny day and do the labour intensive bit on expensive machines in winter, you won't consider transmission. If you can't, you'll weigh transmission against moving your factory to western australia or morocco or texas. Many processes have a drying or a reduction (removing oxygen with electricity or chemicals made from fossil fuels/electricity) or heating step that fills the first profile.

End result is there will be a mix with countries that have less seasonal variation having an advantage in industries that are less flexible (because hitting the worst-case load will require less infrastructure), and countries with more seasonal variation having a huge advantage in flexible industries (as their winter heating bills will subsidize the free summer solar). Transmission will play a role too (but how kuch is uncertain).