Nuclear vs rocket mass heater

Im hoping this title will grab some attention!

So, for years now, and for multiple reasons, I assumed it would be best if people burned wood for heat. Once I learned about rocket mass heaters it only reinforced that idea due to them burning more cleanly, using less fuel and being able to be made by average folks.

Lately, I’ve been hearing a lot if advocacy for nuclear energy. This rubbed me the wrong way. Disasters and bombs were what came to mind, for good reasons. But my (extremely limited) understanding now is that we have the technology and capabilities of building entirely safe nuclear reactors that would be able to energize our world more cleanly than pretty much anything else… assuming theres no more disasters.

Ive also heard that literally millions of people die worldwide every year from burning biomass (wood etc) inside their homes due to unclean air and fires. I dont know if this is true but I have no reason to believe it isnt. Obviously, there are better and worse (more or less safe/more or less efficient) ways to burn wood and many of you already know that and are on the RMH train. Im there too. I particularly like the fact that I can keep myself and my family warm in winter (half of our lives here in Michigan) without having to depend on utility companies and a variety of things outside of our control. But I tend to take things to the extreme and so I envision a world where all heat is nuclear vs a wod where all heat is in the form of rocket mass heaters.

Question is: what would be more desirable from a permacultural point of view? I would guess theres no black and white/simple answer to this but I’m very curious where this conversation may go.

Brody Ekberg wrote:Im hoping this title will grab some attention!

So, for years now, and for multiple reasons, I assumed it would be best if people burned wood for heat. Once I learned about rocket mass heaters it only reinforced that idea due to them burning more cleanly, using less fuel and being able to be made by average folks.

Lately, I’ve been hearing a lot if advocacy for nuclear energy. This rubbed me the wrong way. Disasters and bombs were what came to mind, for good reasons. But my (extremely limited) understanding now is that we have the technology and capabilities of building entirely safe nuclear reactors that would be able to energize our world more cleanly than pretty much anything else… assuming theres no more disasters.

Ive also heard that literally millions of people die worldwide every year from burning biomass (wood etc) inside their homes due to unclean air and fires. I dont know if this is true but I have no reason to believe it isnt. Obviously, there are better and worse (more or less safe/more or less efficient) ways to burn wood and many of you already know that and are on the RMH train. Im there too. I particularly like the fact that I can keep myself and my family warm in winter (half of our lives here in Michigan) without having to depend on utility companies and a variety of things outside of our control. But I tend to take things to the extreme and so I envision a world where all heat is nuclear vs a wod where all heat is in the form of rocket mass heaters.

Question is: what would be more desirable from a permacultural point of view? I would guess theres no black and white/simple answer to this but I’m very curious where this conversation may go.

One notable point, I believe, is that you are only talking about heat.  Nuclear plants produce energy.  I'm all for wood heat, and indeed, use it in my house.  It's far harder to use wood to run say, my well pump.  You can't really compare the two in a meaningful way in my opinion.  

When the smoke inhaler dies, that’s it.  Their kids at least have the opportunity to improve on their situation.  When the reactor melts down, the farm land is lost for generations.  Not worth it in my mind.  Much better to spend the 30 billion dollars on other things.  https://apnews.com/article/business-environment-united-states-georgia-atlanta-7555f8d73c46f0e5513c15d391409aa3

I suffer from wood smoke inhalation and sometimes its very hard to avoid or deal with.
Some communities have banned wood heaters for that reason and the Standards for the heaters have been improved over the last 30 years to reduce the pollution from them.
Often people close them down too much and the fire does not burn cleanly and the fumes dribble out the chimneys and stay low.
I have been a anti nuclear power activist for many years.
I am aware the Industry has ben trying to improve its image, so it may be hard to get clear facts at the moment.
BUT Thorium reactors have been around a long time and are "less" dangerous than Uranium reactors.
Its my understanding that;
- easier to manage
- do not produce bomb garade waste
- waste is slightly better than uranium waste.
- the Chinese are building shipping container sized Thorium reactors to power smaller communities!!

I think comparing them does not make sense.
Nuclear reactors are expensive on a level that is hard to imagine.
With the amount of engineering it takes to build a reasonably safe nuclear reactor, a pollution free wood gasifier and power generation plant can be build.
For me it is a question of whether there is sufficient wood available.

Even rocket stoves if widely adopted in densely populated areas would not be good for air quality or fire risks or biomass supply globally.
What I wished they did with nukes is use all the collosal waste heat they produce.

Sebastian Köln wrote:I think comparing them does not make sense.
Nuclear reactors are expensive on a level that is hard to imagine.
With the amount of engineering it takes to build a reasonably safe nuclear reactor, a pollution free wood gasifier and power generation plant can be build.
For me it is a question of whether there is sufficient wood available.

Well, one nice thing about wood is it grows! So even if we theoretically didnt have enough now, there’s a simple fix for that.

John C Daley wrote:I suffer from wood smoke inhalation and sometimes its very hard to avoid or deal with.
Some communities have banned wood heaters for that reason and the Standards for the heaters have been improved over the last 30 years to reduce the pollution from them.
Often people close them down too much and the fire does not burn cleanly and the fumes dribble out the chimneys and stay low.
I have been a anti nuclear power activist for many years.
I am aware the Industry has ben trying to improve its image, so it may be hard to get clear facts at the moment.
BUT Thorium reactors have been around a long time and are "less" dangerous than Uranium reactors.
Its my understanding that;
- easier to manage
- do not produce bomb garade waste
- waste is slightly better than uranium waste.
- the Chinese are building shipping container sized Thorium reactors to power smaller communities!!

Ive just been hearing so much negativity towards wood heat and pollution and I guarantee these people know nothing of rocket stoves. But even if they did, I doubt everyone could build and feed them efficiently in small towns let alone big cities. I know nothing about Thorium though so that is an interesting thought

Gray Henon wrote:When the smoke inhaler dies, that’s it.  Their kids at least have the opportunity to improve on their situation.  When the reactor melts down, the farm land is lost for generations.  Not worth it in my mind.  Much better to spend the 30 billion dollars on other things.  https://apnews.com/article/business-environment-united-states-georgia-atlanta-7555f8d73c46f0e5513c15d391409aa3

From what I heard, nuclear reactors shouldn’t melt down if designed properly with today’s technology. I heard there hasn’t been one built in 40 years so anything that happened in the past certainly could be improved upon by now.

Trace Oswald wrote:

One notable point, I believe, is that you are only talking about heat.  Nuclear plants produce energy.  I'm all for wood heat, and indeed, use it in my house.  It's far harder to use wood to run say, my well pump.  You can't really compare the two in a meaningful way in my opinion.  

Im mostly talking about heat here for that reason. Im just envisioning a world where we dont have electric lines, natural gas lines and propane lines everywhere. Nuclear could privide the energy for that stuff but wood could provide the heat source. Unless you’re in a city in which case you could be totally reliant on nuclear. Not that I think thats a good idea, I’m just wondering.

Brody, I am negative to the use of wood in the manner many people use it today.
- I am not sure it grows fast enough to replace the timber used by each person today.
- Maybe homes need a certification of insulation before they can fit a wood fire? [ imagine the arguments about that ]
- I see wood wasted by overheating
- Many people appear to think its free so just use it.
- there does not appear to be much forward thinking about maintaining a supply if firewood, some people do plant woodlots, so that is a start.
Frankly in my opinion many people think its somebody eles's task to worry about it.
But a great topic.

As with most things in Permaculture I think that context is key.

Nuclear can be safe, efficient, and abundant if a list of criteria are met.

Unfortunately a lot of nuclear attitudes are the result of earlier generation designs which are still in use, because the life-time efficiency is really important in economic terms when building something like a nuclear power plant.

Also unfortunately there was a bit of over-enthusiasm about nuclear that led to power companies building in... unwise places, like fault lines and tsunami prone coastal locations (see Fukushima). Similarly I wouldn't want to see anyone build a reactor in tornado alley.

There's still the problem of spent fuel for fission though, and we're perpetually 50 years away from operational fusion, though there have been some breakthroughs recently that might mean we're actually 50 years away from fusion now.

I think the reductionist rephrasing of this question though is On-grid vs Off-grid? And the answer to that still depends on context.

Off-grid provides answers to a lot of problems - access, disaster-time reliability, individual innovation and control, etc
On-grid provides answers to others - efficiency of scale, access to expensive technology, dedicated professional support, etc

I personally don't like to knock any approach universally, usually anyway. I'm probably biased towards and against some things, but I try to bite my tongue.

I am going to echo much of what L Johnson just said.  Context is king.  I think we are really looking at two different categories of energy production.

I will start with RMH heaters.  An RMH excels at  localized, homestead heat production.  It is very efficient at turning chemical energy in wood into heat that can be stored in the thermal mass and radiated over time.  If one has a wood lot and a means to harvest, cut and importantly, regrow the wood, I think that an RMH is an excellent source of localized heat.  If one wanted to be truly off/grid, an RMH could be a significant contribution to energy needs.

Nuclear, preferably 4th generation molten salt type reactors, could be an excellent source of grid based electricity.  I specify the 4th generation molten salt reactors because of important built-in safety features and their ability to reduce waste by orders of magnitude (some can actually run on existing waste and radically reduce those stockpiles).  This might be attractive to someone who is reliant on grid-based energy, especially say, in a high-rise apartment.

I specify grid and localized because these are really two different models.  I would not want a grid sized RMH devoted to electrical production.  Technically it could be done but it would consume entire forests in the process.  And likewise, a homestead 4th generation molten salt reactor is in the realm of science fiction at best and probably not a wise choice of energy production.

And I do have one, mostly sour note on fusion.  Fusion has been 30 years away for about 70 years and still is.  There have been a couple of exciting developments that show that fusion is technically possible on earth, outside of nuclear weapons, extremely exotic and energy intensive experiments in highly expensive equipment and of course outside the intense gravity of the sun.  Unfortunately, contrary to popular belief, fusion is not free from radioactive waste.  Actually it is far from.  

The most promising fusion reaction is called D-T fusion (Deturium-Tritium, two isotopes of hydrogen).  And while the reaction does produce non-radioactive helium, it also releases a neutron with an energy of about 14 MeV.  That is a very high energy neutron and it will probably collide with something, either causing a fission event, or more likely bonding and making a new, unstable (radioactive) element.  So while the “exhaust” of D-T fusion is perfectly safe, fusion tends to irritate everything around it.  There are ways to work around this problem and most of the newly-made radioactive material is considered low-level, it is an issue thus far not addressed (because we are nowhere near a practical fusion reactor).  And there are aneutronic reactions—reactions that don’t release neutrons—but they are very difficult to initiate and sustain and as far as I know are presently not a topic of research.

So bring this long-winded response to a conclusion, I think the primary advantage of an RMH over possibly (4th Gen, Molten Salt) nuclear or vice-versa is the context in which it would be used—grid based or localized homestead.

Eric

As some have touched on already, there is a big difference between generating heat directly and generating electricity that can be used to power heaters (among other things). Using wood on a large scale to produce electricity that then has to be transmitted to a home to power a heater doesn't seem like the most efficient use of the BTUs. High efficiency wood burners in the home work very well for direct heating.

Keep in mind that a lot of the energy produced by utilities goes to power industry, not heat or cool peoples' homes. Grocery stores need a lot to keep the freezers/cooler going and the lights on. Office buildings require a lot of energy for HVAC, etc.

It seems to me that each situation might require a unique solution. Until efficient, large-scale fusion comes along, there doesn't seem to be a one-size fits all solution.

Well put Robin.  You said it a few words what took me many.

a lot of the energy produced by utilities goes to power industry

True enough; I doubt that an RMH would enable this photo to be captioned "proudly powered by sticks and junk mail."

Thanks Eric. It helps that I worked in the utility industry for 25 years, mostly in the air pollution clean-up side but I picked up a fair amount of information on generation and where a lot of it went and how it cycled daily, yearly and monthly.

David Baillie wrote:Even rocket stoves if widely adopted in densely populated areas would not be good for air quality or fire risks or biomass supply globally.
What I wished they did with nukes is use all the collosal waste heat they produce.

The current process is to move the environmental disasters "away".  With a rocket mass heater, you own your own shit.  And if a bunch of backwood yokels can get them to burn this clean, imagine what would happen if they became "widely adopted in densely populated areas" - my guess is that there would be a lot of competition for cleaner, cleaner, cleaner.  

Plus, they are very, very, very clean right now.  I made this video 11 years ago.  It frustrates me that "clean" is even brought up

David Baillie wrote:Even rocket stoves if widely adopted in densely populated areas would not be good for air quality or fire risks or biomass supply globally.
What I wished they did with nukes is use all the collosal waste heat they produce.

To address biomass stuff:  you mean like all the paper and cardboard each household receives each year?  And then they try to recycle some and the rest goes to the landfill?  THAT biomass?

And Alan Booker recently gave an EXCELLENT presentation on "Carbon Negative Mass Heaters" where there is a path where each year there is MORE biomass.

https://permies.com/wiki/204703/Carbon-Negative-Mass-Heaters-Alan

Robin Katz wrote:Keep in mind that a lot of the energy produced by utilities goes to power industry, not heat or cool peoples' homes. Grocery stores need a lot to keep the freezers/cooler going and the lights on. Office buildings require a lot of energy for HVAC, etc.

I used to work for the northwest power planning council.  The key is that they are trying to solve future energy needs because people consume more and more and more.  

I would like to suggest that we do two steps:

   - find ways to reduce the energy consumption in our home, while adding luxury

   - find ways to reduce the needs of stuff that consumes energy, while adding luxury

A majority of the energy is being used to heat homes.  

As for the energy consumed by grocery stores:  if people ate more from gardens, then the grocery stores would sell less and, in time, use less power.

And a similar argument can be made for the office buildings ...

There was an interesting Freakanomics podcast a few months ago [link] on nuclear power, and they had a good discussion about the relative safety of the various forms of power. Obviously nuclear deaths get a lot more publicity, but lumberjacks being killed on the job, lung cancer, and solar panel installers falling off roves are far more common.


https://www.engineering.com/story/whats-the-death-toll-of-nuclear-vs-other-energy-sources

and if we ...   all of americans ...   find a path to use half as much energy while enjoying a more luxuriant life ...  that would be half as many deaths.

I think Paul’s point is that RMH’s, even in the middle of dense urban environments where they might have been traditionally considered least applicable, can still function extremely well, burn extremely clean and be fueled not by “wood”, but by ample paper waste found in the middle of a city anyways.  And that paper (junk mail, shipping boxes, etc) would be put to far better use heating a home than being buried in a landfill to slowly decompose into methane which will inevitably seep out.

An RMH is not only an excellent, extremely high efficiency heating device, it is actually a disposal device as well!!

Eric

Eric Hanson wrote: An RMH is not only an excellent, extremely high efficiency heating device, it is actually a disposal device as well!!  

Much also depends on how  "dense" is "dense". I've read that the amount of area planted as "lawns" in the US is enormous. If people coppiced hedges to supplement their use of paper waste, with the efficiency of RMH's, you'd have both the value of a hedge cleaning the air, as well as harvesting sticks for your RMH. If you chose a plant that also gave fruit, you'd be stacking functions further, although you'd have to choose/plan carefully as fruit trees won't bare on the regrowth until it reaches a certain size, but some will work if done right.

Jay,

I should have defined “dense” better.  I was thinking about some high rise apartment with absolutely no green space and completely surrounded by streets, sidewalks, etc.  Basically, I was thinking about the worst case scenario for fueling an RMH.

Eric

Paul,

I have a nerd-level question from one of your posts above.  You stated the majority of generated electricity was going to heat people’s houses (I think I interpreted this question correctly).  Was that statistic specific to the Pacific Northwest region?  Was it a national figure?  Was it something broader?

I am simply curious because energy discussions fascinate me endlessly and I would not have guessed that heating consumed so much electricity—I would have guessed A/C would top heating but I could certainly be wrong.

At any rate, I was just curious about that specific detail.  Thanks in advance.

Eric

I missed this thread first time round, but I think it presents a false dichotomy:

BIOMASS or NUCLEAR

If you were asked to provide eg 1MW of additional electricity right now, the cheapest way to do it is with renewables. Wind and solar is currently cheapest to install and operate per MWhr of produced energy. All other forms of electricity production are more expensive to install and have much long lead times from planning to building to commissioning.

There is no path from the world we are in now, to a world where all energy is from nuclear sources. You would be asking those industries to invest in less cost effective technology. There are lots of (surmountable) engineering issues to resolve with grid scale renewables, but the bottom line is that new installations are nuclear/coal/gas infrastructure are going to be decreasing over the coming decades.

There are similar issues when considering biomass as a stand-alone heat source. There are fundamental limitations on massive national populations depending on biomass for heating and energy. In areas where it is plentiful and populations are sparse it can be great. But it simply cannot scale to high density urban population centres without massive environmental and human harms. It has already been pointed out that the logging industry has a non-trivial annual death rate. Massively expanding this in a world where biomass is used more extensively will lead to greater loss of life. Similarly, those logs need to be harvested in forested areas and transported to urban areas for use. Thousands more lorries on the roads, with implications for traffic accidents, urban air pollution etc… and this is before we even get to start burning the fuel in whatever stoves people are using. Large scale biomass burning - even in rocket stoves - will have an impact on air quality in urban areas.

The UK historically depended on wood for heating, but transitioned into coal during the industrial revolution. Deforestation was rife, and there were strict laws in place regulating who could take what timber. In the modern era, despite massive increases to population size and density, we have more total woodland in the UK than at any point for hundreds of years. switching to biomass would likely trigger an environmental disaster as deforestation runs wild.

My personal view is that hybrids will pretty much always be the queen forward. We burn wood because trees keep falling over on our land. If we don’t burn it, we have to do something else with it. It is a waste product for us being diverted to a higher purpose. That rationale cannot be applied universally.

Similarly, there

Eric Hanson wrote:Paul,

I have a nerd-level question from one of your posts above.  You stated the majority of generated electricity was going to heat people’s houses (I think I interpreted this question correctly).  Was that statistic specific to the Pacific Northwest region?  Was it a national figure?  Was it something broader?

I am simply curious because energy discussions fascinate me endlessly and I would not have guessed that heating consumed so much electricity—I would have guessed A/C would top heating but I could certainly be wrong.

At any rate, I was just curious about that specific detail.  Thanks in advance.

Eric

Good catch.  My habit is to keep my numbers in montana.  Sorry for leaving that bit out.

Paul,

That’s alright.  Although I don’t have a firm number, my inclination is to think that in my warm and humid region, A/C is the dominant energy draw.

Now, if only we could develop a RMAC—Rocket Mass Air Conditioner!  This doesn’t exist does it?

Eric

Eric Hanson wrote:Now, if only we could develop a RMAC—Rocket Mass Air Conditioner!  This doesn’t exist does it?

It isn't a 100% solution, but it helps.  

Eric Hanson wrote:.... comment about electricity for heating....

Policy here in the UK is to phase out gas heating, replacing it with heat pump technology. This increases total electric demand, but also drives investment in renewable energy production. Over time the % of electricity in our grid produced form renewable sources is increasing, so each item that gets replaced by electric power becomes increasingly green, as time passes and the grid continues to shift.

If you measure CO2 emissions, heating using reverse cycle heat pumps produces less CO2 than burning gas domestically for a grid with a fairly small % of renewable. That advantage grows all the time.

Eric Hanson wrote: Although I don’t have a firm number, my inclination is to think that in my warm and humid region, A/C is the dominant energy draw.

Now, if only we could develop a RMAC—Rocket Mass Air Conditioner!  This doesn’t exist does it?

This is a *huge* world wide concern right now from some of the info I've been following - particularly about large cities being "heat islands" and the use of air-conditioning exacerbating that effect.

So I will shamelessly divert the conversation to encourage people to explore high rise level vertical gardening options and encourage cities/buildings to be designed to use such systems. This would not only decrease summer temperatures, but be good for people's mental health as well! Does anyone know if a whole-building air system can be run to dehumidify without specifically lowering the air temperature, and would doing that save much electricity? (thinking of Eric's concern about humidity - our house can feel positively "clammy" if the humidity gets too high, even if the temperature isn't unreasonable) City Permaculture often focusses on roof-tops, but I think if some of our best minds thought of good ways to improve cost-effective vertical gardening, it could be part of the solution.

Back to Rocket mass heaters and apartments: My sister's apartment years ago had concrete floors. Can anyone think of ways to use a Rocket heater to heat that mass? My brain is saying some sort of water system laid on top of the concrete in what would have to be at least a couple of inches thick, but then you'd need a Rocket heater that doesn't do the Boom/Squish thing. I wouldn't think thin air pipes would work due to air resistance??? This is way beyond my knowledge level of fluid dynamics and engineering, so I'm thinking out loud here.

"They say" a lot  of things, unfortunately. I'm against nuclear because it's not clean and because of murphy's law, meltdowns are always possible, and wood is better and SO much cheaper, when properly burned. Imagine a small city of 200,000 people that has some smart regulations that conserve power without seriously affecting quality of life. Now imagine the river of sewage that those 200,000 people produce. Now imaging how much biogas can be produced from that sewage. Now imagine how many willow trees can be fertilized by the leftover sludge. Now imagine how many leaves and twigs from these coppiced willows can be fed to cattle. The sticks from coppicing can be gassified as well. Now the gas furnaces for apartment blocks (or even central city heating) can also run free piston stirling engines, each generating 100 KW of electricity. This is all possible, and we have all the technology. It just needs some scaling up.

Michael Cox wrote:I missed this thread first time round, but I think it presents a false dichotomy:

BIOMASS or NUCLEAR

If you were asked to provide eg 1MW of additional electricity right now, the cheapest way to do it is with renewables. Wind and solar is currently cheapest to install and operate per MWhr of produced energy. All other forms of electricity production are more expensive to install and have much long lead times from planning to building to commissioning.

There is no path from the world we are in now, to a world where all energy is from nuclear sources. You would be asking those industries to invest in less cost effective technology. There are lots of (surmountable) engineering issues to resolve with grid scale renewables, but the bottom line is that new installations are nuclear/coal/gas infrastructure are going to be decreasing over the coming decades.

There are similar issues when considering biomass as a stand-alone heat source. There are fundamental limitations on massive national populations depending on biomass for heating and energy. In areas where it is plentiful and populations are sparse it can be great. But it simply cannot scale to high density urban population centres without massive environmental and human harms. It has already been pointed out that the logging industry has a non-trivial annual death rate. Massively expanding this in a world where biomass is used more extensively will lead to greater loss of life. Similarly, those logs need to be harvested in forested areas and transported to urban areas for use. Thousands more lorries on the roads, with implications for traffic accidents, urban air pollution etc… and this is before we even get to start burning the fuel in whatever stoves people are using. Large scale biomass burning - even in rocket stoves - will have an impact on air quality in urban areas.

The UK historically depended on wood for heating, but transitioned into coal during the industrial revolution. Deforestation was rife, and there were strict laws in place regulating who could take what timber. In the modern era, despite massive increases to population size and density, we have more total woodland in the UK than at any point for hundreds of years. switching to biomass would likely trigger an environmental disaster as deforestation runs wild.

My personal view is that hybrids will pretty much always be the queen forward. We burn wood because trees keep falling over on our land. If we don’t burn it, we have to do something else with it. It is a waste product for us being diverted to a higher purpose. That rationale cannot be applied universally.

Similarly, there

A few thoughts:
UNDESIGNED biomass energy production would indeed be a disaster. It must be designed. Cities generate a huge amount of biomass, in a form that is easy to extract energy from, both technologically and through plants.
Using less energy, through efficiency, is probably key. In permaculture terms, that means getting as much use as possible out of the energy as it travels from source to sink.
Above, I talked about wood gasifiers. What about skipping that part and going to 12 inch J-tube systems for heating apartment buildings and generating power? Maybe a soapstone mass for retaining heat around the intake end of the stirling engine? Willow grown using the leftovers from biogas production would be the main fuel.
No lumberjacks must die.

Centralized nuclear using these massively expensive power stations is a very different engineering challenge than a distributed "home based" system.

I've been doing a lot of research into this topic recently, and on the small scale, there are designs (like Thorium cast into a large block of glass) which simply don't have the mass of radioactive material to go critical.

The glass block just gets hot but not so hot that it melts the glass.

There is an old technology called a nuclear battery which converts heat to electricity using an array of simple metal/metal oxide thermocouples joined together to form what is called a thermopile. You could build a Thorium based nuclear battery that generates 12 Volts which in turn charges a battery bank that would last for decades.

But there is currently no commercial solution for the home scale, and access to radioactive material is highly restricted. This is really an off-limits technology to everyone except the government and large corporations. They aren't too keen on moving away from this Energy as a Service model.

Trace Oswald wrote:

Brody Ekberg wrote:Im hoping this title will grab some attention!

So, for years now, and for multiple reasons, I assumed it would be best if people burned wood for heat. Once I learned about rocket mass heaters it only reinforced that idea due to them burning more cleanly, using less fuel and being able to be made by average folks.

Lately, I’ve been hearing a lot if advocacy for nuclear energy. This rubbed me the wrong way. Disasters and bombs were what came to mind, for good reasons. But my (extremely limited) understanding now is that we have the technology and capabilities of building entirely safe nuclear reactors that would be able to energize our world more cleanly than pretty much anything else… assuming theres no more disasters.

Ive also heard that literally millions of people die worldwide every year from burning biomass (wood etc) inside their homes due to unclean air and fires. I dont know if this is true but I have no reason to believe it isnt. Obviously, there are better and worse (more or less safe/more or less efficient) ways to burn wood and many of you already know that and are on the RMH train. Im there too. I particularly like the fact that I can keep myself and my family warm in winter (half of our lives here in Michigan) without having to depend on utility companies and a variety of things outside of our control. But I tend to take things to the extreme and so I envision a world where all heat is nuclear vs a wod where all heat is in the form of rocket mass heaters.

Question is: what would be more desirable from a permacultural point of view? I would guess theres no black and white/simple answer to this but I’m very curious where this conversation may go.

One notable point, I believe, is that you are only talking about heat.  Nuclear plants produce energy.  I'm all for wood heat, and indeed, use it in my house.  It's far harder to use wood to run say, my well pump.  You can't really compare the two in a meaningful way in my opinion.  

Today's Nuclear is not your parents Nuclear.       If you were choosing standard nuclear I would go with rocket stoves,  but thorium nuclear reactors are far far far safer than the old 3 mile island reactors.

Myself I would go with thorium nuclear reactors combined with hydrogen,   you kill so many bad pollution stones with that route...     But I am a realist,      The money is flowing to the old nukes and that is not changing as I don't get to decide that.....

Yeah those old nuke stations primary function was the manufacture of weapons grade fission material. Electricity was the convenient byproduct since nobody's going to blow up a civilian power station but they sure would blow up a nuclear weapons enrichment facility LOL

There are currently 75 community sized rocket mass heaters in use in the USA with Europe building more of them. I worked at one before switching to hydroelectric and honestly they are a huge part of the answer for communities.

The one I worked at was small and only produced 31 megawatts but it was something. It took garbage destined for the landfill and made something of use for communities. This was renewable power, 24/7, and unlike most renewable power, gave synchronization to the grid.

If there was recycling in the USA it would be one thing, but with the collapse of the recycling industry, and more and more people getting packaging from Amazon, I think it’s better to burn it and reduce the landfill waste to 5% and allow people to have more renewable power.

At present we import 25% of our electricity and that says nothing about the need for local reactive power generation. With the baghouse getting emissions to 90% less that what was allowed, the question is why are we not burning more garbage in massive rocket mass heaters?

75 plants is not enough for 300 million people

The new free heat movie trailer is here starring Rocket Mass Heaters at center stage:

For more info, also take a look at https://freeheat.info

Based on the earths population and our current lifestyle. I don't think that biomass/wood could power and meet all of our energy needs.
I do thin that wood heat is viable for folks who:
who don't rent,
who don't live in the city,
who lives in a less humid areas of the world,
who has enough land to sustainable harvest their own firewood,
who have laws in place that makes sure it is sustainably harvested vs cutting down say virgin forest,
etc, etc.

That said I wish we could reduce how much heat and energy that we use as a society. I wish that each country/city/house was more self-sufficient or at least pre-paid for their resources. I wish that we generated less waste and polutions and mess for the future generation.

If we ever get around to having a functional and affordable nuclear fusion reaction, I would be happy to see one in every single home.

I would support more farms burning their agricultural waste to produce bio-char to increase their farm fertility, and using the heat from that process to power the grid and also to power any on-site energy intensive process that they have.