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Comment by Beltiras | Hacker News Reader

Three most important things for 1.5C are:

1. Stop burning coal 2. Get shipping off oil and onto renewables 3. DAC efforts need to be stepped up, both biological and technological

All of those are achieved by turning to Gen 4 nuclear reactors. MSRs are now entering trial phases [1] where nuclear energy generation is not as strictly regulated as in the States. Miniaturization efforts have found solutions where such a power plant [2] could be cost effective for shipping.

DAC efforts are a bit strange. I've looked a bit into tree planting and haven't found anything that looks like it scales with investment. I can't purchase a product knowing it will result in extra efforts, or put another way, if a billionaire would pour in a billion dollars, it wouldn't scale up the operation proportionately to the increased funds. Technological DAC is a solved problem that would scale but needs a power source.

4th gen reactors are the only thing that tackles these points on all fronts.

[1] http://thorconpower.com/project/ [2] https://www.seaborg.co/

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Would not be a hacker news climate thread without someone jumping in immediately with nuclear.

I am not opposed to the technology in a meaningful way but the problem is that the conditions in which nuclear can thrive - regulatory scheme, public perception of climate change risk, long time horizon infrastructure development, $$$ - non nuclear renewables easily outcompete.

I wonder how the nuclear folks think about this. The tech doesn’t exist in a numerical vacuum of efficiency and dollars per watt. It lived inside a complex ecosystem within which it doesn’t really seem competitive.

I don't think they think about it at all. My university had a strong nuclear research program and I took some classes from the professors in the field. It's clearly really hard, to the point that even PhD level intellects can only do it when they're hyperfocused on the nuts and bolts of the physics. I think even beyond that, maybe for national security reasons, people in the nuclear industry don't get outside their bubble much. I'm sure if any of them took a weekend of genuinely trying to understand why it wasn't cost-competitive they'd understand it better than me, but then they'd fall behind in their 'real' research. So they lobby for more state support without ever questioning why they need it.

Right now wind+solar account for less than 1% of global electric generation.

I'm highly skeptical that prices can remain low as that scales out to 10-40% of electric generation, given constraints on things like rare earth metals. There is also the issue of equipment wearing out relatively quickly compared to conventional/nuclear plants.

SMRs, built using mass production rather than one-off construction, and possessing safety qualities far beyond current reactors, will be necessary to provide safe, reliable, clean and cheap energy alongside "renewables", IMNSHO.

Less than 1%? Not true in the slightest.

In the US alone, wind and solar (including rooftop) produce approximately 11% (about 53GW average) of electrical energy given the very latest data (last 12 months rolling) from: https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... (and this should be updated today)

The US consumes about 485GW average electricity, compared to the world total of 2485GW average. So approximately 1/5th.

So US solar + wind ALONE is at least 2% of global electric generation (50GW/2485GW > 2%), twice your claim (again, this is just the solar and wind in the US compared to world total electricity). I suspect your figures are far outdated (not uncommon in this field...).

EDIT: This is still using old data (2018), but it shows that 7.5% of global electricity energy (again, energy, not mere nameplate power) comes from solar+wind: https://yearbook.enerdata.net/renewables/wind-solar-share-el...

To me it is pretty simple. I look at places like Germany and Denmark and see how natural gas is booming. I then compare that to nations with a lot of nuclear. Nuclear is expensive, take a long time to build, and can not compete with the price of using a combination of renewables and fossil fuels. It is however the only current example of energy grids that work without fossil fuels.

My political interest in the topic is exclusively in not having fossil fuels being burned for power and heat. The economics of combining renewables and fossil fuels only works to a point, as illustrated by the energy grid of Germany and Denmark. Both countries now need to go to over capacity and battery technology to further reduce fossil fuel usage, and for about the same reason that nuclear has problem competing, battery technology and overcapacity cost too much.

As more countries in EU reach the same point we get fewer countries that need to buy during periods of overcapacity (as show by negative prices). This reduces the interest in building more renewables, and it becomes more attractive to stay at 100% renewable at peak conditions and have fossil fuels picking up everything when its not at peak. This is a typical example of a local maximum and a Nash equilibrium. Any action that goes towards 100% renewables at peak condition are competitive and any action that goes beyond 100% during peak conditions are noncompetitive. Such countries then get stuck, with the problematic consequences that fossil fuels continue to burn.

1$/watt capital costs and 2.5c/kwhr. This blows every other competitor out of the water. I was stunned when I started to research the economics of 4th gen. It's going to win in the end.

If Greenpeace only knew the damage they did back in the 80's and 90's... Granted that nuclear power back then was primitive and dangerous.

You are absolutely right. Most of the innovative projects are putting up shop in less developed countries exactly for this reason. Once proven there the regulatory hindrances in the west will disappear because for industrial purposes nothing else will be able to compete.

MSRs can produce thermals in excess of 2000C which is enough for most smelting operations. This will increase efficiency almost twofold. This will mean all smelting operations will move to areas where the technology can be employed. Because of the economic incentives there will be countries with emerging economies (and already are, see Indonesia) that will take advantage.

This will take a decade or two to percolate but the writing is on the wall. Failing to react to it will only make dinos out of the countries unwilling to change.

They didn't. The nuclear industry failed to innovate themselves out of increasing costs. It is regulatory bodies that set the requirements, not Greenpeace, and those requirements are based on risk calculations.

It could be that the industry is just dysfunctional. But it could also be that nuclear tech is just way harder in the real world than what some people seem to think.

The nuclear industry is still wearing the ball and chain of solid fuels. Everything wrong with nuclear energy is due to that single engineering faux pas. Oak Ridge ran an MSR for 5 years. It would be tragic if it couldn't be mended but it can. I'm 100% sure that Gen 4 will dominate energy generation within 2 decades. I'd put money on that.

I'd take the other side of that. Fifty bucks?

I meant as an investment. I'd see more return than 1:1.

Fair enough, hope you're right!

In case you did not know the abbreviations:

DAC: direct air capture

MSR: molten salt reactor

Building enough reactors is impossible in the time we have left. Especially if you want to go for unproven tech that is just now entering trials.

Thorcon aims to transform a shipyard into a factory for these things. Their plan is to mass-produce 250MW reactors.

There are more than 60,000 power plants in the world, the bulk of which are fossil fuels. Replacing them, with a continually growing power demand as newly middle-class individuals begin to consume more, is effectively impossible without radical change on a planetary level.

Never mind the concrete production for all of the new plants alone would release a staggering amount of CO2.

Even if someone figured out fusion this afternoon, and could start construction of one plant on each continent (sans Antarctica) this year, with the plants going online late next year, we'd still need radical change to hold us over for (likely) the couple of few decades it would take to build enough of the facilities.

Also consider ICE vehicles are still something like 90% of the annual sales in the world too. If you outlawed the production of ICE vehicles in every country in the world today, in 30 years you'd still have many millions of those vehicles on the road being used.

Concrete, plastics, livestock... there are many facets to this problem.

Absolutely. We need all angles at the problem to find a solution. We also need to mitigate the damage we know can't be prevented. Shipping is 12% of CO2 emissions. It's a little bit harder to nail down (found a staggering figure of 46% of all emissions) how much coal contributes but together with shipping they are more than half of all emissions. If you are tackling a hard problem and a solution to half of it is on your doorstep, please answer the bell.

The world need on the order of 100k 250MW (thermal) reactors to replace today's energy consumption. How many are they planning to produce per year.

If it only delivers .5% of the worlds energy consumption it's still an enormous (and welcome) feat.

Yeah, sure. Build as much nuclear as you can reasonably integrate into a grid that primarily runs on renewables. But don't trust in Thorium to somehow fix our problem.

Thorcon is using 20% enriched U-235. Their design can accomodate the Thorium fuel cycle in the future but for now it's mostly repurposed nuclear wastes.

I don't remember the figures. There are plenty of videos on Youtube with presentations from the Thorcon team. I think it's 250MW electric, 500MW thermal that the design delivers.

The US uses 4 trillion kWh per year. Assuming 3MW wind turbines at 30% capacity factor, you'll need around 3.5 billion wind turbines. They take around 23 million kWh to manufacture (each), so you'll need to find the energy for that. However, that's not really enough, as the entire economy needs to be carbon-neutral. Electricity usage accounts for about 40% of the total US energy usage, so you'll actually need to multiply everything by 2.5.

Seriously, I understand the "we only have 10 years to do anything" line, but the math is so far from adding up, it completely defeats the point. The only realistic way to achieve the 10 year goal is to radically cut energy usage.

A 3 MW wind turbine producing at 30% capacity factor generates

3000 * 0.3 * 24 * 365 = 7,884,000 kWh per year.

4 trillion kWh annually would require

(4 * 10^12) / 7884000 = 507,357 turbines

Not 3.5 billion.

Fair point - I did the calc all at once and screwed up my parentheses. My point still stands. How realistic is it to manufacture 500,000 x2.5 = 1.25 million wind turbines, needing 27 trillion kWh to do so, in 10 years?

That's not going to happen. Nor are thousands of nuclear reactors going to be built in 10 years. Nor is the US going to cut its primary energy use by 60% in 10 years. Nor is the combination of all-of-the-above going to make the US carbon neutral in 10 years. Nor should we give up on continued incremental progress after another 10 years have passed without fully solving the problem.

It's always possible to make climate change even worse by burning more fossil fuels. Regardless of whatever dangerous threshold of emissions has passed in 10 years, it doesn't make sense to resign ourselves to burning the rest of the fossil fuels. I'm afraid that the hardline "we need to have solved this emissions problem in 1X years" rhetoric is counterproductive. It asks too much and will prompt fatalism and/or cynicism when the deadline has passed, there are still billions of living people who need to make decisions affecting the future, and the problem still isn't "done with."

> I'm afraid that the hardline "we need to have solved this emissions problem in 1X years" rhetoric is counterproductive. It asks too much and will prompt fatalism and/or cynicism when the deadline has passed

This is a risk yes, media have a big part to play here to try and build on positive inertia. A good example of the opposite of this is Australia in ~2005 vs ~2015 we went from enough political will to create a carbon tax (that was hugely successful is dropping our emissions in a short period of time) to removing it and likely never going back. IMO this was largely due to medias constant fighting in this direction (to serve those who were lobbying hard in this direction).

The hardline approach does seem to have wakened a larger group of people to speak out and support trying to reduce how much worse the climate crisis will get in the coming decades. That combined with more frequent and intense natural disasters might just keep things moving. However, I've learnt never to be surprised by our collective short term memory when counter narratives are constantly bombarding us through media channels.

I agree with you. I support people doing the right thing even for mistaken reasons. That's why I don't normally criticize comments saying that we need to solve the problem in <some arbitrary number of years> even though I believe that "deadline" approach is technically incorrect. I don't look forward to the backlash after these various deadlines pass in the 2030s though.

Fortunately, there is also a longer term trend of battery storage costs and renewable generation costs continuing to fall. It may be short term reactions to wildfires that guide Australian energy investment in the next couple of years, but it will be the technological improvements that keep low-carbon options on top in the next couple of decades.

The headlines absolutely do not help. They turn off people like me, who care deeply about sustainability, let alone your average reader. Nor do those promoting complex/high-tech solutions, or ideas like "you do your part if you buy an EV". The simple fact is - a sustainable, CO2 neutral civilization essentially only has the energy available daily from the sun to sustain itself (unless you include nuclear). This is orders of magnitudes less than our current energy usage. Unless you want another stone age, a compromise is necessary.

I agree as a population we need to reduce our energy usage but I will point something out.

> CO2 neutral civilization essentially only has the energy available daily from the sun to sustain itself (unless you include nuclear). This is orders of magnitudes less than our current energy usage.

The solar energy hitting the earths surface (forgetting what is absorbed in upper atmosphere contributing to winds) is really quite large. An example is I grew up in a territory/state that is 1.421 million square KMs in area. Taking the global average [0] of solar radiation hitting the surface of the planet the amount daily energy hitting the ground in just that area is 1,421,000,000 (square meters) * 6kWh = 8,526,000,000 kWh or 8.562 TWh each day (on average)

Yes we can only access a small percentage of this through technology and practical land/sea use but that is an awful lot of energy in a relatively small part of the globe (NT Australia). But while "those promoting complex/high-tech solutions" are not always promoting useful things, the history of renewable energy is one of incremental improvement and small gains to efficiency. I agree it won't happen over 10 years, and no single technology will hold the solution to all our problems, but I do believe a combination of social change and iterative technology improvements can work together to greatly reduce us making the problem worse over the coming decades.

Better communication of the science and engineering of what is possible is absolutely needed, but so is communication of the science predicting how bad things can get if we don't do anything.

[0] https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on...

Is this calculation as simple as: it takes order of 10 years to build a reactor using existing tech, and we don’t have that long left?

With an added "and that is at the current buildout rate, which basically keeps every qualified person busy". 10x-ing the rate at which we build reactors would require training more personnel and (depending on the type of reactor you want to build) 10x-ing things like the huge machines we need to forge pressure vessels.

That can't be a simple calculation given the tremendous disagreement and controversy over how much time is "left" (until what?)

The problem is that we will need thousands of reactors. 10 years for a single one won't cut it.

Thorcon means to retrofit shipyards to mass produce the reactors and service as refueling stations.

Nuclear is not going to happen in time and other technologies that are completely uncontroversial are already running circles around it for the past decade in terms of cost and growth (which would be negative for nuclear). I don't expect meaningful results to come from nuclear investments in the next decades. This would be the same period of time most modern countries will cross the 50-100% covered by renewable energy mark. Much of the current deployed nuclear capacity might actually end up being retired in the same period because most of it is already on the edge of it's economic life and replacements are controversial from a cost perspective (never mind the safety). The status quo is that nuclear plants are multi billion $ projects that take decades to plan and realize and that have very dubious economics.

100% renewable everywhere is not going to happen everywhere in the next two decades; but there are plenty of countries shooting for that on a 15-20 year time line. In 20 years, most of the remaining countries will be actively planning to catch up in a hurry or simply end up importing excess energy from more clued in places at a premium. Even approved plans for nuclear plants (of which there are preciously few) would probably take longer to realize; and lets face it, mostly these plans reside in some drawer gathering dust.

Nuclear is not a solution short term (< 20 years) or mid term (< 40 years) and long term (>40 years) it will have to be cost competitive with vastly cheaper than today renewables. Which is a different way of saying the winter olympics will be organized in hell regularly.

Nuclear security alone makes it a non starter from a cost point of view. Any nuclear reactor requires 24x7 security to prevent people from depopulating their local area with a bit of explosives. Micro reactors make excellent dirty bombs and with tens of thousands of them around it's more a question of when than if somebody manages to do this. The resulting security requirements alone makes them impractical, even if they would be able to compete with the renewable solutions that will be common in a few decades. These are likely to be vastly cheaper than what we have today. The main question is how many orders of magnitude cheaper things can get before people stop caring about the price. Below a certain price, using excess renewable energy to synthesize all sorts of fuels will also become vastly cheaper than refining oil no matter how inefficient that is from an energy point of view (and it's actually not that bad). Ironically, refining oil requires a lot of energy, which comes from ... renewables. That's why Texas leads everyone else with solar and wind deployments.

1 $/watt capital costs and 2.5c/kWhr for 4th gen nuclear. Solar needs to be a heck of a lot cheaper to compete with that.

All you need for 4th gen to appeal to regulators is one country starting it and showing success. Indonesia will test it out. Depending on success of failure, other countries will follow suit.

Solar bids already already dip way below that regularly for several years. By the time any of this is built, << 1c per kwh should be the norm. That only requires a 2x cost reduction which is nothing considering cost trends over the last decade with solar. Think orders of magnitude here.

> Technological DAC is a solved problem that would scale but needs a power source.

If nuclear was as safe as technological DAC is solved we'd all be dead already from radiation ten times over.

I'm not talking about currently running solid-fuel reactors that burn only 0.3% of their fuel. I'm talking about 4th gen liquid fuel reactors that manage to burn 99.7% of their fuels (bonus: can burn the waste fuels old reactors leave behind), are walk-away safe and the wastes they do leave have a half-life of hundreds of years instead of millions.

DAC that you can feed power into and that way stream more CO2 into sequestration solutions is mostly a solved issue at scale [1]. Sequestration is also a solved issue [2].

  [1] https://carbonengineering.com/
  [2] https://climeworks.shop/how-it-works/

> Get shipping off oil and onto renewables

Good luck moving container ships without diesel. You'll also have to put the passenger airlines and air cargo carriers completely out of business.

It is honestly something we need to do but doing so would require every continent to rely entirely upon the resources on that continent. It would also mean all of those hundreds of millions to billions of newly middle class folks around the world would have to give up their newly won quality of life and go back to living how they were before.

We either have to radically change society on nearly every level or cross our fingers and hope a humanitarian (alientarian?) fleet of alien ships show up in orbit with highly advanced technology that can replace all of our energy needs AND actively remove huge amounts of CO2 out of the air.

Jet fuel can be generated carbon neutrally with these 4th gen reactors. They provide high enough thermals to split water and hydrogen energy efficiently and any process where you generate hydrogen you can very easily produce hydrocarbons instead. We have the technology. It's economical. It's safer than any alternative ALREADY HERE. Solar is not carbon free and environmentally friendly. Silicon smelting is a really dirty process. None of the alternatives have the capability to scale the same way.

Assuming they can produce jet fuel, I doubt it would be anywhere close to enough to replace the current fossil fuel.

I've looked before and it is hard to get a decent figure due to military/private/commercial passenger flights, non-passenger military flights, freight flights etc but

>Collectively, United States air carriers burn through 17 billion gallons of jet fuel annually

https://thepointsguy.com/guide/cost-of-fueling-an-airliner/

I think that figure is only commercial passenger flights.

It's simple really. They need to be cheaper than fossil fuels. Can't find the link right now but I remember reading about it being possible with a little subsidy (way less than oil companies are getting now).

Good luck moving container ships without diesel.

The US navy already has a massive part of their fleet running without diesel. It's not technology that's holding back carbon-free shipping.

You'll also have to put the passenger airlines and air cargo carriers completely out of business.

Why is that required to get shipping off oil and onto renewables?

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