We need massive construction of a few standard nuclear reactors. We need to federalize their fuel supply and recycling. The power company would operate the reactor, sell the power, and our tax dollars would take care of the fuel cycle outside of the plant.

We need to go quite hard on regenerative farming. It wouldn't surprise me if this switch alone could pull the surplus of carbon out of the air, and put it back into the topsoil of farms, where it belongs. Industrial farming is about as close as you can get to hydroponics these days, except it's done outside with 1" of topsoil.

Wind and solar are great, but storage is a huge issue, both in terms of stress to the grid, and uneven availability. There are some project plants that show 50% round trip efficiency for storage... which is better than throwing out a surplus.

We also could encourage energy hungry industries to be more interactive loads... for example... aluminum smelting can be scaled up or down quite a bit (though not to zero, to match adjustable electricity pricing)

We could electrify the freight rail system in the US. It almost happened 100+ years ago. Improvements in trans-shipping could also reduce the need for liquid fuels in transport by reducing long haul trucking.

We should get rid of plastic bottles, and go back to reusable glass containers. Single use plastics should be considered "unsuitable for new designs". (as they say with electronics components)

Heat pumps are just fancy air conditioners... and they are far more efficient at both heating and cooling if they are coupled to an in-ground coolant loop We should subsidize them.

Does that fit in what you're looking for?

Synthetic fuel:

https://www.prometheusfuels.com/news/dude-wheres-my-fuel

The most promising tech. Make fuel from CO2 captured from the air. We can keep using our existing infrastructure. Buys us a lot of time without destroying our current way of life.

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Carbon Capture: (Twitter accounts) @CharmIndustrial @noya_carbon @heirloomcarbon @ebbcarbon @livingcarbon

https://www.ycombinator.com/companies/airmyne

> Net Power, a startup that built the world’s first zero-emissions fossil-fuel power plant in Texas. Earlier this year, Net Power fired up a $150-million power plant that burns natural gas but has the ability to capture 100% of its carbon emissions.

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Emission free manufacturing:

> What Gross is pursuing with his new company, Heliogen, offers a way forward for renewable energy to be applied to manufacturing processes for cement, lime, coke, and steel — some of the most energy intensive and polluting industries that exist in the world today.

https://techcrunch.com/2019/11/19/heliogens-new-technology-c...

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Geo-engineering

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Nuclear

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Food:

Modified feed to lessen cattle methane emission. https://www.ycombinator.com/companies/alga-biosciences

Real milk without cows. https://www.ycombinator.com/companies/brown-foods

I work on nuclear micro reactors (specifically this one: www.usnc.com/mmr) and there is big promise here to make many reactors soon and cheap. Their size of 15 MWe is too small to fully power human civilization which requires 20 TW of primary energy. For reactors with a 60 year life, that would require a population of 300,000 reactors sustained by a production cadence of 5000 reactors per year. That's actually comparable to the production rate of wide body aircraft. Even if such production rates are not acheived, these small reactors do not suffer xenon poisoning and can use thermal storage to produce dispatch power. It's like a zero carbon natural gas peaker, and can provide the needed backbone for intermittent renewables. The optimal mixes for many locations around the US are something like 10% dispatch nuke, and there rest wind and solar. It's one of the few energy solutions that looks a lot like a fossil fuel source, by virtue of it's high temperature heat, the fact it can be used on demand, can be located anywhere where it is needed, etc.

Curious what your thoughts are on market penetration with regard to anti-nuclear thought. I'm for it btw. What is soon?

In terms of production capacity and industrial capability, it is mostly there. As an example, the recently unopened nord stream pipeline produced 200,000 pipe sections with similar dimensions and mass to the Micro Modular Reactor pressure vessel - in just a few years. Nuclear fuel costs are dirt cheap and production rates can be ramped pretty quickly - it's the magic of nuclear energy density.the reactor tech is more or less fifty years old with some design to build changes. Culturally, the zero-carbon push, volatile and political fossil markets, and perhaps an end in sight to the shale boom - it's completely changed the customer conversation compared to just a few years ago. Ultimately, energy scarcity is going to be the push for full market deployments. And we may be approaching that. All the delays and waddling will dissolve in the face of cold hard necessity.

If we were to run with this design to completely power civilization, is there enough helium supply? If not, could it be adapted to either argon or some other inert gas?

Could the fuel get recycled at end of life if regulatory approval were given?

Not yet exploited: I'm a big fan of deep bore geothermal energy using a closed loop. Here's an example from a company trying to make it work. Idk if they can actually do it but it can def be done by a large enough entity.

https://www.youtube.com/watch?v=PtQmGPmyLA0

Build some pipes in the ground. Pump an anti-freeze like fluid into the ground so it heats up. Bring it up on the other side and the heat from the fluid heats some steel pipes submerged in water so the water turns to steam. Steam turns turbine and electricity is generated.

You can either send it straight to market or you could store it via batteries, flywheels, compressed air, your choice.

Lots of areas where energy could be lost but the earth is hot so it's not like we're depleting a resource

Theres an mit offshoot using microwAve beams to vaporize rock in a pretty neat process that leaves a glassy and structural tunnel wall not unlike the nuclear subterrene concept from 70s. Pretty cool stuff.

Donating that much is a serious commitment. To what types of initiatives have you donated the money? What you think are the most promising technical solutions (the original question)?

checkout salk.edu

>It’s the reason why America is cutting its energy output.

In addition, there's the rapid decline curves of wells producing "tight oil". [1]

[1] - https://energycentral.com/c/og/visualizing-us-oil-gas-produc...

That is a great chart - if looked at carefully, especially when comparing to the rig count, which had a huge drop at the start of the pandemic but has been steadily increasing for a couple years... it is clear the the reduced output is not due to slowing of drilling, but to the steeper decline of output from non-traditional wells (fracking, horizontal drilling, etc.) The engineers in the oil & gas industry were predicting this eventuality back in 2009 when I was working on an app in that arena.

The main reason I point this out is to make sure people realize that "America is reducing its energy output" is political rhetoric and not productive to the conversation. The reality is that our oil & gas output is not sustainable in the long-term no matter where your politics fall, and we need new solutions.

There’s an incredible amount of oil on the gulf coast of the USA . You are misled

Nuclear and natural gas. Forget tilting at windmills.

Embrace limits.

There's a limited energy budget at Earth's surface.

Humans have benefitted by ransacking a treasure store of energy which accumulated over 100--300 million years, and will quiet possibly not be recharged in the remaining span of habitable life on Earth (about another 800 million -- 1 billion years). Even absent energy concerns, we've also been ransacking rich mineral deposits some dating to the earliest eras of life on the planet (banded iron formations, the result of blue-green algae growing 3 billion years ago). Absent ore-formation through minerological and biological processes which concentrate minerals to levels which make further extractuion and purification viable, we'd be stuck with far fewer choices for materials.

The largest challenges in degrowth are not technological but political, cultural, economic, fiscal, and ultimately about shared beliefs, values, and vision.

Over nearly 50 years of awareness of, reading on, and researching this problem, that's become abundantly clear, and hopes of a successful negotiation of this particular transition are not high.

The energy landscape is largely known and has been for the past 70-150 years. Solar, wind, hydroelectric, geothermal, and biomass.

We're already making use of much or all the available biomass (as food, with considerable fossil inputs), hydro, and goethermal resources. Solar can be ramped up, as can wind. Both produce power of a different scope, cost, and quality (availability, variability) than what advanced technological countries have come to rely on.

Nuclear is an option but faces its own issues: limite fuel (uranium and plutonium, possibly not so much in the case of thorium), major political and social-organisation risks, and of course a very long-tail disposal risk extending beyond the span not only of all our social institutions but of civilisation itself --- tens of thousands of years.

William Ophuls and Thomas Homer-Dixon are two authors in particular who have been looking at the political challenges of adapting to ecological limits.

I strongly recommend all Ophuls' work, though Ecology and the Politics of Scarcity (first published in 1977, revised ~1994) and Plato’s Revenge (2011) are probably the best starting points. The first secion of Ecology in particular makes one of the most cogent arguments for the Limits to Growth premise I’ve found anywhere.

At Worldcat:

https://www.worldcat.org/title/ecology-and-the-politics-of-s...

https://www.worldcat.org/title/ecology-and-the-politics-of-s...

https://www.worldcat.org/title/platos-revenge-politics-in-th...

Also available via Archive Org:

https://archive.org/search.php?query=william ophuls

Ophuls has a website with more recent writings, though the essays are missing from the present-online version:

https://web.archive.org/web/20190311104851/https://ophuls.or...

Thomas Homer-Dixon is referenced by Ophuls several times and seems closest in spirit to his work:

https://homerdixon.com/

I don't understand the logic of resigning ourselves to adapting to degrowth and scarcity when human civilization is on the cusp of being able to harvest extra-terrestial resources, which absolutely dwarf resources available on Earth.

This argues that off-world activity will be mostly conducted by robots. That doesn't conflict with my point about the vast stores of resources available to human civilization outside Earth.

There are vast stores of resouces available to human civilisation under your feet.

Space mining faces not only distance and energy costs, but extreme environments, lack of ore formation, highly limited element availability in numerous cases, and the challenge of delivery for Earth use without leaving a literal smoking crater.

Space is for virtually all intents an informational domain. Not one of matter.

Keep in mind that even in the one field for which space-based methods were most widely and plausibly promoted, telecommunications, it is literally easier and more useful to wrap the globe in glass than to incur the round-trip time costs of Earth-to-orbit transmission.

Starlink overcomes some of the time delay but seems unlikely to match the sheer bandwidth of fibre-optic communications.

Mining a single metallic asteroid would increase the supply of certain metals many fold:

https://www.smithsonianmag.com/smart-news/asteroid-16-psyche...

And there are millions of these types of asteroids in the solar system.

Extra-terrestrial resources also include the sunlight that is currently being beamed into empty space all around the Earth, that could otherwise be harvested by massive solar farms. There is millions of times more sunlight missing the Earth than reaching the Earth.

Setting up an infrastructure for harnessing these resources would be a massive endeavor but once the infrastructure is set up, the amount of resources that come to be accessible to human civilization grows by orders of magnitude.

Even granted the unlikely premise that relevant materials are more abundant in space than on Earth, the points remain that:

- Good planets are hard to find.

- That the available habitable planetary / surface area is only modestly larger than that of Earth alone, and vastly less hospitable (see: https://xkcd.com/wiki/index.php/1389 https://www.explainxkcd.com/wiki/index.php/1389:_Surface_Are...).

- Costs of space travel in both financial and resource terms would be prohibitive for moving more than a vanishingly small fraction of the human population off-planet.

- Any space colonists would have to first create and then maintain a habitable ecosystem in whatever remote environment they chose to occupy (under conditions which make contemporary epithets of "eco-fascism" appear to descirbe a positively libertarian regime).

And ... given all that, the challenge of living sustainbly on this one small fragile beautiful blue-wite gem we happen to have lucked into coming to existence on will remain for any foreseable future.

Space isn't a get-out-of-jail-free card.

Assuming we accept your pessimistic take on the limits on technology's ability to bring down the cost of creating off-world habitats for humans and transporting people between them and Earth:

You can still massively grow the Earth-based economy, without damaging its biosphere, by extracting the resources it needs from outside Earth.

This does not require moving people between planets, just energy and goods, which are much less costly to transport than people, and can become extremely affordable to transport as infrastructure is set up to facilitate it.

Are there then no limits at all?

What are the limits, if any?

When are they met, presuming constant-rate (that is to say, exponential) growth?

How much is that time extended if you expand the limit by a factor of 10? 100? 1,000?

Do you honestly think that the Earth can support 80 billion, or 800 billion souls, or 8 trillion, at present G-7 nation levels of affluence?

A 4% annual growth rate corresponds to a doubling time of about 17.5 years.

2^3.3 ~= 10

2^6.6 ~= 100

2^9.9 ~= 1000

Keep in mind that your binding constraint isn't your most abundant resource / capable sink, it's the least.

The limits are far into the future, at the very least close to when we harness a significant fraction of the energy emitted by the sun, which is trillions of times more energy than human civilization uses today.

Is energy then the most pressing limiting factor presently?

On what do you base this assessment?

Some in the Green Movement --- a wildly nonuniform clade, for what it's worth --- view the engrossed obsession with accruing fiscal wealth whilst ignoring all exteranlised impacts on other humans and the environment as a whole as itself grossly misanthropic, and worse.

That said, broad-brushing epithets deserved or otherwise seems a poor foundation on which to base common cause and understanding, and I'd respectfully request you refain from doing so. In the spirit of HN's commenting guidelines if for no grander principle:

Be kind. Don't be snarky. Have curious conversation; don't cross-examine. Please don't fulminate. Please don't sneer, including at the rest of the community.

Comments should get more thoughtful and substantive, not less, as a topic gets more divisive.

When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

Eschew flamebait. Avoid unrelated controversies and generic tangents.

Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something.

https://news.ycombinator.com/newsguidelines.html

Much of the green movement, yes. Elon Musk is part of the green movement, but highly philanthropic.