Energy storage: Difference between revisions

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In the pursuit of green [[energy]], storage is needed for 2 reasons:
In the pursuit of green [[energy]], storage is needed for 2 reasons:
# To smooth out the intermittency of [[solar]] and [[wind]] power.
# To smooth out the intermittency of [[solar]] and [[wind]] power.
# To store energy in [[electric vehicles|electric vehicles]] without gasoline or diesel.
# To store energy in [[electric vehicles]].


==How much would be needed?==
<small>Note: This page does not include [[thermal energy storage]].</small>
 
==Types / Candidates==
{|class="wikitable"
!Type
!Status
|-
|[[Sodium-ion batteries]]
|Good potential / needs investment.
|-
|[[Sodium-sulfur batteries]]
|Good potential / needs investment.
|-
|[[Hydrogen gas]]
|Okay for some applications, but too lossy & platinum-intensive for others.
|-
|[[Lithium ferro phosphate batteries]]<!--(LiFePo4 or LFP)-->
|Okay if used in moderation. A bit too lithium-intensive to be a general solution.
|-
|[[Lithium-ion batteries]] <small>(NMC/NCA type)</small>
|Not scalable enough: Too [[cobalt]]-intensive.
|-
|[[Lithium-sulfur batteries]]
|Can't handle enough charge cycles.<!--
|-
|Lithium Titanate (Li4Ti5O12 or LTO)
|? -->
|-
|[[Lead-acid batteries]]
|Toxic / hazardous.
|-
!colspan=2|Stationary storage only (power grid, not vehicles)
|-
|[[Iron redox flow batteries]]
|Good potential / needs investment.
|-
|[[Compressed air energy storage|Compressed air]]
|?
|-
|[[Pumped hydro]]
|Only viable in rare geographical locations.
|-
|[[Flywheels]]
|?
|-
|[[Gravity blocks]]
|Not viable: Outrageously high environmental footprint of construction.
|-
|}
<small>For more details, read the wikipage of each energy storage type. Links are in the table.</small>
 
So far, sodium-based batteries seem to have the [[the great battery challenge|most hope]] of being a widespread solution - along with iron-based batteries for stationary energy storage.
 
<!--
==How much energy storage might be needed?==
Some quick estimates:


===Vehicles===
===Vehicles===
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}}
}}
{{dp
{{dp
|timescale
|storage_timescale
|24 hours
|24 hours
|How big the "buffer" of energy storage would have to be to be resiliant against weather fluctuations
|How big the "buffer" of energy storage would have to be to be resiliant against weather fluctuations
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}}
}}
{{calc
{{calc
|other_energy.tfc * timescale
|other_energy.tfc * storage_timescale
|terajoules
|terajoules
|other_energy_storage_needed
|other_energy_storage_needed
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There are more options for this type of energy storage, because it's stationary (not moving in a vehicle).
There are more options for this type of energy storage, because it's stationary (not moving in a vehicle).


===How much storage is this really?===
These numbers might be reused on other wikipages to assess the large-scale viability of various types of energy storage. Don't worry if you're not familiar with <code>terajoules</code> as an [[energy/units|energy unit]].
Most people aren't familiar with terajoules. Let's express it instead in terms of "gallons of gasoline equivalent energy" per person.
{{dp
|world.population
|7.95 billion
}}
{{calc
|(other_energy_storage_needed + vehicle_energy_storage_needed) / world.population
|gallons gasoline per capita
}}
 
This much energy has to be stored in some other way (not gasoline).
 
==Types==
 
===Hydrogen gas===
[[Hydrogen gas]] does not occur in nature, but can be generated using green [[energy]] (by [[electrolysis]]).
 
====Vehicles====
 
Car engines '''can''' viably be built to burn hydrogen gas instead of [[gasoline]]. However, this isn't as efficient as building an electric car powered by [[hydrogen fuel cells]] (which use chemistry to convert the hydrogen energy back to electricity, which powers electric motors that run the car).
 
But even hydrogen fuel cells might not be quite efficient enough:
{{dp
|<nowiki>electrolysis.efficiency</nowiki>
|<nowiki>80%</nowiki>
|<nowiki>Energy efficiency of producing hydrogen & oxygen gases from water</nowiki>
|<nowiki>Hydrogen made by the electrolysis of water is now cost-competitive ...</nowiki><br /><nowiki>
www.carboncommentary.com › blog › hydrogen-made-by-the-electrolysis... </nowiki>
}}
{{dp
|<nowiki>hydrogen_fuel_cell.efficiency</nowiki>
|<nowiki>50%</nowiki>
|<nowiki>Electric energy efficiency of an average hydrogen fuel cell</nowiki>
|<nowiki>Hydrogen Fuel Cells Fact Sheet</nowiki><br /><nowiki>
www.californiahydrogen.org › uploads › files › doe_fuelcell_factsheet</nowiki>
}}
{{calc
|<nowiki>electrolysis.efficiency * hydrogen_fuel_cell.efficiency</nowiki>
|<nowiki>%</nowiki>
}}
This is only half the charge-discharge efficiency of lithium-ion batteries.
 
Hydrogen fuel cells contain rare minerals.{{qn}}
 
Hydrogen gas requires a [[pressurized fuel tank]], which is significantly heavier than a gasoline tank{{qn}} but probably not as heavy as a lithium-ion battery pack, for the same amount of energy. Safety concerns are similar to other pressurized fuels such as [[natural gas]] or [[propane]].
 
====Heating and cooking====
* Homes could be heated with hydrogen gas instead of natural gas.
* Gas-powered stoves could easily be adapted to burn hydrogen.
 
 
 
===Lithium-ion batteries===
 
[[Lithium-ion batteries]] are the current standard for electric cars and most small gadgets (phones, laptops, etc).
 
Is there enough lithium?
{{dp
|<nowiki>li_ion.cell_voltage</nowiki>
|<nowiki>3.6 volts</nowiki>
|<nowiki>Voltage of a single lithium-ion cell.</nowiki>
|<nowiki>https://www.cei.washington.edu/education/science-of-solar/battery-technology/</nowiki><br /><nowiki>
https://www.fluxpower.com/blog/what-is-the-energy-density-of-a-lithium-ion-battery</nowiki><br /><nowiki>
It's 3.6 volts for the "cobalt type" of lithium-ion battery. Other types might have a very slightly different voltage.</nowiki>
}}
{{dp
|<nowiki>li_ion.lithium_by_energy</nowiki>
|<nowiki>0.3 grams per amp hour li_ion.cell_voltage</nowiki>
|<nowiki>To store a given amount of energy in lithium-ion batteries, this is how much lithium would be needed.</nowiki>
|<nowiki>https://batteryguy.com/kb/knowledge-base/how-to-calculate-the-lithium-content-in-a-battery/</nowiki><br /><nowiki>
The article says lithium per amp hour. We convert this to lithium per watt hour (energy), by including the cell voltage.</nowiki>
}}
{{dp
|<nowiki>lithium.reserves</nowiki>
|<nowiki>18425000 tonnes</nowiki>
|<nowiki>Lithium metal: Total global mineral reserves</nowiki>
|<nowiki>https://www.statista.com/statistics/268790/countries-with-the-largest-lithium-reserves-worldwide/</nowiki><br /><nowiki>
Added up all the countries: 9,200,000 + 4,700,000 + 1,900,000 + 1,500,000 + 750,000 + 220,000 + 95,000 + 60,000 = 18,425,000 metric tons</nowiki>
}}
{{dp
|<nowiki>li_ion.cobalt_by_energy</nowiki>
|<nowiki>20 kg per 100 kilowatt hours</nowiki>
|<nowiki>To store a given amount of energy, in lithium-ion batteries (cobalt type), this is how much cobalt would be needed.</nowiki>
|<nowiki>https://www.energy.gov/eere/vehicles/articles/reducing-reliance-cobalt-lithium-ion-batteries</nowiki>
}}
{{dp
|<nowiki>cobalt.reserves</nowiki>
|<nowiki>7.1 million tonnes</nowiki>
|<nowiki>Cobalt metal: Total global mineral reserves</nowiki>
|<nowiki>https://www.statista.com/statistics/264930/global-cobalt-reserves/</nowiki>
}}
{{calc
|vehicle_energy_storage_needed * li_ion.lithium_by_energy
|% lithium.reserves
}}
{{calc
|other_energy_storage_needed * li_ion.lithium_by_energy
|% lithium.reserves
}}
 
Just barely. How about cobalt?
{{calc
|vehicle_energy_storage_needed * li_ion.cobalt_by_energy
|% cobalt.reserves
}}
{{calc
|other_energy_storage_needed * li_ion.cobalt_by_energy
|% cobalt.reserves
}}
 
Not viable.
 
Solutions:
* Using some other version of lithium-ion batteries, which doesn't depend so much on cobalt.
* Marketing cheaper electric vehicles with much smaller battery capacity, for city driving only.
* [[Walkability]].
* Extracting [[lithium from seawater]] (the viability of this may be questionable).
 
Other important stats:
{{dp
|<nowiki>li_ion.charge_discharge_efficiency</nowiki>
|<nowiki>85%</nowiki>
|<nowiki>When you charge a lithium-ion battery, this much of the energy is stored. The rest is lost as heat.</nowiki>
|<nowiki>Range: 80 to 90 %</nowiki><br /><nowiki>
from wikipedia; haven't found original source yet</nowiki>
}}
{{calc
|<nowiki> li_ion.charge_discharge_efficiency </nowiki>
|<nowiki>%</nowiki>
}}
 
 
 
===Iron-redox flow batteries===
 
[[Iron-redox flow batteries]] are a type of battery made from mostly [[iron]], an extremely abundant metal.
 
But this battery comes with a few challanges:
* The iron has to be kept ''molten'' at very hot temperatures.
** Hence it's only viable to build a battery the size of a [[shipping container]], not smaller.
** This battery is '''not''' suited for electric vehicles.
 
There ''would'' be enough iron:
{{dp
|iron.reserves
|85 billion tonnes
|Global iron reserves - iron metal recoverable
|Source: Global iron ore reserves 2010-2021 - Statista
}}
{{dp
|irfb.energy_by_mass
|85 watt hours per kg
|Specific energy of an iron redox flow battery
|Using half the "theoretical specific energy" of 170 watt hours per kg. This battery hasn't really been commercialized yet, so it's safe to assume that we won't be close to the theoretical maximum in the near future.
<br /><br />Source: https://dornsife.usc.edu/labs/narayan/all-iron-redox-flow-battery/
}}
{{calc
|other_energy_storage_needed / irfb.energy_by_mass
|% iron.reserves
}}
 
 
 
===Lead-acid batteries===
Besides being toxic, there wouldn't be enough lead to scale these up:
{{dp
|lead.reserves
|90 million tonnes
|
|Global lead reserves 2010-2021 - Statista
}}
{{dp
|lead_acid.energy_by_mass
|38 watt hours per kg
|Specific energy of a lead-acid battery
|Source: Lead-acid battery - Wikipedia
}}
{{dp
|lead_acid.lead
|60%
|How much of a lead-acid battery is lead, by mass
|Source: Lead-acid battery - Wikipedia
}}
{{calc
|other_energy_storage_needed * lead_acid.lead / lead_acid.energy_by_mass
|% lead.reserves
}}
 
The only advantage is that some people already have a few lead-acid car batteries they could use in some DIY home energy storage solution.
 
 
 
===Flywheels===
[[Flywheels]] store energy mechanically by spinning a heavy rotor at high speeds. This has been implemented before, both inside vehicles {{x|but not necessarily storing enough energy to power the vehicle for more than a few kilometers at best}} ''and'' in stationary electrical systems {{x|with a much higher specific energy}}.
 
If flywheels are made mostly of [[steel]] (which is mostly iron), we ''would'' have enough metal to build enough of them:
{{dp
|flywheels.practical.energy_by_mass
|5 kWh per (450 kg)
|
|Based on this product as an example: http://www.rosseta.de/texte/pdat-t4.pdf
}}
{{dp
|flywheels.theoretical.energy_by_mass
|500 kJ/kg
|
|https://web.archive.org/web/20100710052927/http://www.pddnet.com/article-next-gen-of-flywheel-energy-storage/
}}
{{calc
|other_energy_storage_needed / flywheels.practical.energy_by_mass
|% iron.reserves
}}
{{calc
|other_energy_storage_needed / flywheels.theoretical.energy_by_mass
|% iron.reserves
}}
 
However, it is unknown how much of other metals might be needed to make the flywheel systems - for example the rare earth magnets involved in the motor/generator components. This page needs more research.
 
How much [[energy]] would it take to refine all that steel?
{{dp
|energy.tfc
|9938 Mtoe/year
|Global total final energy consumption
|Source: Key World Energy Statistics 2020
}}
{{dp
|steel.recycled.production.energy_by_mass
|sqrt(1665*4170) watt hours per kg
|
|<cite>How much energy does it take (on average) to produce 1 kilogram of...</cite>https://www.lowtechmagazine.com/what-is-the-embodied-energy-of-materials.html
}}
{{dp
|steel.new.production.energy_by_mass
|sqrt(5550*13900) watt hours per kg
|
|<cite>How much energy does it take (on average) to produce 1 kilogram of...</cite>https://www.lowtechmagazine.com/what-is-the-embodied-energy-of-materials.html
}}
{{calc
|steel.new.production.energy_by_mass * other_energy_storage_needed / flywheels.practical.energy_by_mass
|months energy.tfc
}}
However, the energy needed to ''manufacture'' the flywheels from the steel, might be vastly more. This page needs more research.
<!-- TODO: labor footprint - could work from (required * steel_industry.workers 40 hours/week / steel.production) idk -->
 
 
Viability of flywheels in vehicles is unknown too. Flywheel-based vehicles have existed for over a century, but they don't store enough energy to last more than a kilometer. Perhaps vacuum-sealed electrical type of flywheel could store more energy {{x|this page needs to clarify this more in previous paragraphs}}, but would the bumps of the road cause energy losses too quickly? This page needs more research.


<!-- TODO: ===Compressed air=== -->


<!-- TODO: ===Gravity blocks=== -->
TODO:
* Improve the above commented-out calculations.
* Put them in templates {{Grid energy storage}} and {{Vehicle energy storage}}
* Use the templates on the wikipage of each energy storage type.
-->
[[Category:Energy storage]]

Latest revision as of 15:57, 26 February 2024

In the pursuit of green energy, storage is needed for 2 reasons:

  1. To smooth out the intermittency of solar and wind power.
  2. To store energy in electric vehicles.

Note: This page does not include thermal energy storage.

Types / Candidates

Type Status
Sodium-ion batteries Good potential / needs investment.
Sodium-sulfur batteries Good potential / needs investment.
Hydrogen gas Okay for some applications, but too lossy & platinum-intensive for others.
Lithium ferro phosphate batteries Okay if used in moderation. A bit too lithium-intensive to be a general solution.
Lithium-ion batteries (NMC/NCA type) Not scalable enough: Too cobalt-intensive.
Lithium-sulfur batteries Can't handle enough charge cycles.
Lead-acid batteries Toxic / hazardous.
Stationary storage only (power grid, not vehicles)
Iron redox flow batteries Good potential / needs investment.
Compressed air ?
Pumped hydro Only viable in rare geographical locations.
Flywheels ?
Gravity blocks Not viable: Outrageously high environmental footprint of construction.

For more details, read the wikipage of each energy storage type. Links are in the table.

So far, sodium-based batteries seem to have the most hope of being a widespread solution - along with iron-based batteries for stationary energy storage.

Retrieved from "https://olam.wiki/index.php?title=Energy_storage&oldid=1890"