Decarbonize the energy supply

How to produce enough energyThis includes more than just the status-quo of electricity production. It also includes all the additional electricity that would be needed to replace fossil fuels in vehicles and in industries. (for the world) without burning fossil fuels?

This page is about the ongoing challenges involved.

The renewables approach (+ energy storage)

Solar & wind power would have to be the main energy sources in most parts of the world.
- Most people don't live near regions suitable for hydropower or geothermal power. discussion TODO: link to discussions about what regions they are suitable
- Biofuels are a no-go, because they cause global hunger and deforestation. Biomass waste is a fine alternative, but its global production rate is fundamentally small compared to the fossil fuels we're trying to replace.

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 to this.

Batteries might be scalable enough to smooth out the day/night cycle of solar. (...)( Best bet would be either sodium-ion or iron redox flow batteries. )
- But the seasonal fluctuations of wind & solar probably need far more energy storage capacity.
  - See discussion on other energy storage types and whether any could provide enough capacity.

More discussions:

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. Here's a comparison:

Type of nuclear power	Problems if scaled up
Type of nuclear power	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 Additional 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:

Vehicles - possible options

Battery-based electric vehicles (EVs)

Most EVs today use lithium-ion batteries (NMC type). Scaling these up is unsustainable due to the amount of cobalt in them. 💬 discussion Need to mention 3 issues about cobalt (put this on the linked page maybe): Child labor, scarcity, and the possibility of mining the ocean floor (since conventional mining wouldn't be able to produce enough to make all cars electric). All this would be even worse if cobalt isn't fully recovered in EV battery recycling.
- Best alternatives (so far) hold somewhat less of a charge (i.e. the vehicle gets less range"Range" refers to the distance the vehicle can travel after 1 full charge.). 💬 discussion TODO: Add to this page a simple comparison between NMC, LFP and sodium-ion, in terms of typical expected EV range.
  - LFP batteries are cobalt-free but still lithium-based. 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 batteries are quite new to the market (in 2024), and the hope is that they'll become a lot cheaper than existing batteries. That way, EVs could be cheap and durable, with the only tradeoff being the lack of range.^{[QUANTIFICATION needed]} Probably still good enough for city/suburban living.
  - For city buses: LFP and sodium-ion are both perfectly fine. The lower energy-per-weighti.e. the fact that more battery mass is needed to hold the same amount of electricity 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-powered 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-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: Estimate: How much hydrogen would have to be stored (stocked) at any given time, for the supply chain to work (let's say if it's all produced through nuclear power)? Probably a lot less than what it would take to smooth out the seasonality of renewables - I need to write a page explaining why.

Ammonia-powered vehicles

This section has not been filled in yet. discussion Research needed: How does ammonia compare to hydrogen in terms of: * Energy-efficiency of ammonia production * Energy-efficiency of ammonia fuel cells * Catalyst metals required in ammonia production and in ammonia fuel cells. Which metals and how much of them? * Storage (mass of container materials required per unit of energy stored)
Note that this research is also needed for assessing the viability of using ammonia energy storage to smooth out the seasonal variations of renewables.

More discussions

This section has not been filled in yet. discussion TODO: People also have other concerns about renewables and energy storage. I need to direct readers to pages that address those concerns.