Archive:000/Decarbonize the energy supply

How to produce enough energy (for the world) without burning fossil fuels?

Ongoing challenges

The {renewables + energy storage} approach

• Solar & wind power would have to be the main sources, because other renewables are limited to very specific geographic regions.
• Batteries might be enough to smooth out the day/night cycle of solar. But the seasonal fluctuations of wind & solar probably need far more energy storage capacity. See discussion on whether any other energy storage types could be enough.
• Most solar panels today would probably be unsustainable or even impossible to scale up, due to having too many scarce minerals in them. See discussion on alternatives.

More discussions 💬 discussion TODO: People also have other concerns about renewables and energy storage. I need to direct readers to pages that address those concerns.

• Is there enough land to scale up wind power (without causing significant ecological damage)?

The nuclear approach

Considering the different types of nuclear power, it seems that thorium power is the one with the least problems:

Type of nuclear power	Problems if scaled up
	Fuel scarcity	Weapons proliferation	Nuclear waste
Conventional nuclear power (status quo)	Problem	Low risk	Problem
Conventional small nuclear reactors	Problem	High risk	Problem
Uranium-238 breeder reactors iAdditional benefit: Uranium-238 reactors would make use of existing nuclear waste, which has been left over from decades of conventional nuclear power.	Abundant	High risk	Almost none
Thorium-232 breeder reactors	Abundant	Low risk	Almost none
Fusion (not viable yet)	Abundant	Low risk	Almost none
^ For more details, follow these links in the leftmost column.

Actions / discussions / next steps:

• Why isn't thorium power a thing yet?
• Would small (shipping-container-sized) thorium reactors be viable?

Vehicles

(electric and/or hydrogen and/or ammonia)

Battery electric vehicles

• Most EVs today use NMC-type lithium-ion batteries - but scaling these up is unsustainable due to the amount of cobalt in them.
• LFP batteries are cobalt-free, but hold somewhat less of a charge (i.e. the vehicle gets less range). LFP batteries are still lithium-based, and lithium scarcity would be somewhat a problem but not as bad as cobalt.
• Sodium-ion batteries are made from abundant materials - they don't have any mineral-scarcity problem (probably). But they hold even less of a charge than LFP. Sodium-ion EVs are still usable, but their range isn't great.^{[QUANTIFICATION needed]} Might still be good enough for a lot of people, if the EV is cheap enough.
• For buses, LFP and sodium-ion are both perfectly fine. The lower energy-density is not a problem, because buses need extra weight at the bottom anyway for stability.

Actions/discussions:

• Next steps for sodium-ion batteries 💬 discussion Is it true that sodium-ion EVs are available in China already, and just not in North America? If sodium-ion batteries are on the market now, how does their cost compare to lithium-based batteries so far?
• How well are EV batteries recycled?

Hydrogen-fueled vehicles

• Hydrogen fuel-cell vehicles would be unsustainable to scale up, because of the amount of platinum & palladium in the fuel cells. 💬 discussion This page needs to mention: Hydrogen production also requires these same metals but it can be done with much less of them and thus could probably be done sustainably.
• Hydrogen combustion vehicles don't have this problem, but their fuel economy (efficiency) is lower.^{[QUANTIFICATION needed]} 💬 discussion How bad would this be an issue if renewables or nuclear were to be the main energy sources? 💬 discussion Discussion needed: How much hydrogen would have to be stored at any given time, in such a scenario (let's say if it's all produced through nuclear power)? Probably a lot less than the "renewables + energy storage" approach. I need to write a page explaining why.

Ammonia-fueled vehicles

This wiki needs more research on this:

How does ammonia compare to hydrogen in terms of:

• Production energy-efficiency
• Fuel cell energy-efficiency
• Catalyst metals required for ammonia production and for fuel cells
• Storage (materials required per unit of energy)

More / See also

This section has not been filled in yet.