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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]]. |
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| ==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: |
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| ===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). |
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| ===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
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| |(other_energy_storage_needed + vehicle_energy_storage_needed) / world.population
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| |gallons gasoline per capita
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| }}
| |
| | |
| This much energy has to be stored in some other way (not gasoline).
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| | |
| ==Types==
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| ===Hydrogen gas===
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| [[Hydrogen gas]] does not occur in nature, but can be generated using green [[energy]] (by [[electrolysis]]).
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| ====Vehicles====
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| | |
| 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
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| |<nowiki>electrolysis.efficiency</nowiki>
| |
| |<nowiki>80%</nowiki>
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| |<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>
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| }}
| |
| {{dp
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| |<nowiki>hydrogen_fuel_cell.efficiency</nowiki>
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| |<nowiki>50%</nowiki>
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| |<nowiki>Electric energy efficiency of an average hydrogen fuel cell</nowiki>
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| |<nowiki>Hydrogen Fuel Cells Fact Sheet</nowiki><br /><nowiki>
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| www.californiahydrogen.org › uploads › files › doe_fuelcell_factsheet</nowiki>
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| }}
| |
| {{calc
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| |<nowiki>electrolysis.efficiency * hydrogen_fuel_cell.efficiency</nowiki>
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| |<nowiki>%</nowiki>
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| }}
| |
| This is only half the charge-discharge efficiency of lithium-ion batteries.
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| Hydrogen fuel cells contain rare minerals.{{qn}}
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| | |
| 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]].
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| | |
| ====Heating and cooking====
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| * Homes could be heated with hydrogen gas instead of natural gas.
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| * Gas-powered stoves could easily be adapted to burn hydrogen.
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| | |
| ===Lithium-ion batteries===
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| | |
| [[Lithium-ion batteries]] are the current standard for electric cars and most small gadgets (phones, laptops, etc).
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| | |
| Is there enough lithium?
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| {{dp
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| |<nowiki>li_ion.cell_voltage</nowiki>
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| |<nowiki>3.6 volts</nowiki>
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| |<nowiki>Voltage of a single lithium-ion cell.</nowiki>
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| |<nowiki>https://www.cei.washington.edu/education/science-of-solar/battery-technology/</nowiki><br /><nowiki>
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| https://www.fluxpower.com/blog/what-is-the-energy-density-of-a-lithium-ion-battery</nowiki><br /><nowiki>
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| It's 3.6 volts for the "cobalt type" of lithium-ion battery. Other types might have a very slightly different voltage.</nowiki>
| |
| }}
| |
| {{dp
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| |<nowiki>li_ion.lithium_by_energy</nowiki>
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| |<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>
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| |<nowiki>https://batteryguy.com/kb/knowledge-base/how-to-calculate-the-lithium-content-in-a-battery/</nowiki><br /><nowiki>
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| The article says lithium per amp hour. We convert this to lithium per watt hour (energy), by including the cell voltage.</nowiki>
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| }}
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| {{dp
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| |<nowiki>lithium.reserves</nowiki>
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| |<nowiki>18425000 tonnes</nowiki>
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| |<nowiki>Lithium metal: Total global mineral reserves</nowiki>
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| |<nowiki>https://www.statista.com/statistics/268790/countries-with-the-largest-lithium-reserves-worldwide/</nowiki><br /><nowiki>
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| 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
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| |<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>
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| |<nowiki>https://www.energy.gov/eere/vehicles/articles/reducing-reliance-cobalt-lithium-ion-batteries</nowiki>
| |
| }}
| |
| {{dp
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| |<nowiki>cobalt.reserves</nowiki>
| |
| |<nowiki>7.1 million tonnes</nowiki>
| |
| |<nowiki>Cobalt metal: Total global mineral reserves</nowiki>
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| |<nowiki>https://www.statista.com/statistics/264930/global-cobalt-reserves/</nowiki>
| |
| }}
| |
| {{calc
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| |vehicle_energy_storage_needed * li_ion.lithium_by_energy
| |
| |% lithium.reserves
| |
| }}
| |
| {{calc
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| |other_energy_storage_needed * li_ion.lithium_by_energy
| |
| |% lithium.reserves
| |
| }}
| |
| | |
| Just barely. How about cobalt?
| |
| {{calc
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| |vehicle_energy_storage_needed * li_ion.cobalt_by_energy
| |
| |% cobalt.reserves
| |
| }}
| |
| {{calc
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| |other_energy_storage_needed * li_ion.cobalt_by_energy
| |
| |% cobalt.reserves
| |
| }}
| |
| | |
| Not viable.
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| | |
| Solutions:
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| * Using some other version of lithium-ion batteries, which doesn't depend so much on cobalt.
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| * Marketing cheaper electric vehicles with much smaller battery capacity, for city driving only.
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| * [[Walkability]].
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| * Extracting [[lithium from seawater]] (the viability of this may be questionable).
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| | |
| Other important stats:
| |
| {{dp
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| |<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
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| |<nowiki> li_ion.charge_discharge_efficiency </nowiki>
| |
| |<nowiki>%</nowiki>
| |
| }}
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| | |
| ===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:
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| * The iron has to be kept ''molten'' at very hot temperatures.
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| ** Hence it's only viable to build a battery the size of a [[shipping container]], not smaller.
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| ** This battery is '''not''' suited for electric vehicles.
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| ===Flywheels===
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| ===Compressed air===
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| ===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]] |