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Electric vehicles/Fossil fuel powered: Difference between revisions

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Electric vehicles/Fossil fuel powered (view source)

Revision as of 00:58, 4 April 2023

16 bytes removed ,  4 April 2023
Simplified the calculations
(Accounted for the different GHG of different fuels. I still plan to refactor the calculations so the steps are less awkward.)
(Simplified the calculations)
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==Long answer==
==Long answer==


''For coal power plants:''
The following calculations compare the average gasoline-powered vehicle with the average [[lithium-ion battery]]-based electric vehicle. Greenhouse gas emissions are in tonnes CO<sub>2</sub> equivalent (CO2eq):
 
<!-- TODO: add a popup box for assumptions:
* no jevons paradox
* battery is the main difference in production emissions (EV as compared to gas car) (amortized over lifespan)
-->
 
'''Usage emissions''' <!-- not technically a heading. we don't want mediawiki to generate a table of contents. -->
 
{{dp
{{dp
|<nowiki>electric_car.efficiency</nowiki>
|<nowiki>electric_car.fuel_economy_equivalent</nowiki>
|<nowiki>100 miles per 34.6 kWh</nowiki>
|<nowiki>100 miles per 34.6 kWh</nowiki>
|<nowiki>The "gas mileage" equivalent for an average electric car.</nowiki>
|<nowiki>The "gas mileage" equivalent for an average electric car.</nowiki>
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|<nowiki>coal_power_plant.efficiency</nowiki>
|<nowiki>coal_power_plant.efficiency</nowiki>
|<nowiki>33%</nowiki>
|<nowiki>33%</nowiki>
|<nowiki>How much of the coal's heat energy becomes electricity</nowiki>
|<nowiki>How much of the coal's combustion heat energy becomes electricity</nowiki>
|<nowiki>Transformative Power Systems | Department of Energy</nowiki><br /><nowiki>
|<nowiki>Transformative Power Systems | Department of Energy</nowiki><br /><nowiki>
https://www.energy.gov/fecm/transformative-power-systems</nowiki>
https://www.energy.gov/fecm/transformative-power-systems</nowiki>
}}
{{dp
|natural_gas_power_plant.efficiency
|33%
|How much of the gas combustion heat becomes electricity
|This stat is for simple (older tech) natural gas power plants. The efficiency is the same as for coal and nuclear power. The process is the same: Heat boils water, creates steam to drive a turbine.
}}
}}
{{dp
{{dp
Line 47: Line 61:
|<nowiki>25.4 miles per gallon gasoline</nowiki>
|<nowiki>25.4 miles per gallon gasoline</nowiki>
|<nowiki>Gas mileage of an average American new car</nowiki>
|<nowiki>Gas mileage of an average American new car</nowiki>
|<nowiki>This datapoint is conformable with [electric_car.efficiency], because the calculator understands 'gallon gasoline' as an energy unit.</nowiki><br /><nowiki>
|<nowiki>This datapoint is conformable with [electric_car.fuel_economy_equivalent], because the calculator understands 'gallon gasoline' as an energy unit.</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
Citation:</nowiki><br /><nowiki>
Citation:</nowiki><br /><nowiki>
"The average fuel economy for new 2020 model year cars, light trucks and SUVs in the United States was 25.4 miles per US gallon (9.3 L/100 km)."</nowiki><br /><nowiki>
"The average fuel economy for new 2020 model year cars, light trucks and SUVs in the United States was 25.4 miles per US gallon (9.3 L/100 km)."</nowiki><br /><nowiki>
- Fuel economy in automobiles - Wikipedia</nowiki>
- Fuel economy in automobiles - Wikipedia</nowiki>
}}
{{calc
|electric_car.efficiency * li_ion.charge_discharge_efficiency * (100% - power_grid.losses) * coal_power_plant.efficiency
|car.fuel_economy
|fuel_economy_if_coal
}}
<!--SCRAP: In other words, there's a ''very slight'' increase in overall fuel efficiency, but it's not much.-->
''For natural gas power plants'':
Some have the same efficiency as coal power plants (33%). Results would be about the same as above. {{x|Although in theory, coal and natural gas have different GHG emissions per unit energy{{x|which we didn't factor in, and maybe we should for best precision}} - in practice, they're about the same, due to [[natural gas#fugitive emissions]]. Both are close enough to gasoline, for the purpose of the calculations on this page.}}
''Other'' natural gas power plants {{light|(the more advanced "combined-cycle" type)}} are more efficient: up to 60%:
{{dp
|<nowiki>natural_gas_combined_cycle_power_plant.efficiency</nowiki>
|<nowiki>60%</nowiki>
|<nowiki>How much of the natural gas's heat energy becomes electricity, in an advanced "combined cycle" power plant</nowiki>
|<nowiki>This is considered a "maximum" value - the best natural gas power plants achieve this.</nowiki><br /><nowiki>
Simpler/older natural gas plants (no combined cycle) have only an efficiency of 33%, same as [coal_power_plant.efficiency].</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
Read more: https://energyeducation.ca/encyclopedia/Natural_gas_power_plant</nowiki>
}}
{{calc
|electric_car.efficiency * li_ion.charge_discharge_efficiency * (100% - power_grid.losses) * natural_gas_combined_cycle_power_plant.efficiency
|car.fuel_economy
|fuel_economy_if_advanced_natural_gas
}}
<!--SCRAP: In this case (electric car + advanced natural gas power), we do in fact cut our emissions in half. But this doesn't apply to older, simpler natural gas power plants.-->
{{dp
|<nowiki>ev.battery</nowiki>
|<nowiki>65.2 kWh</nowiki>
|<nowiki>Energy capacity of the average electric vehicle battery</nowiki>
|<nowiki>Useable battery capacity of full electric vehicles</nowiki><br /><nowiki>
https://ev-database.org/cheatsheet/useable-battery-capacity-electric-car</nowiki><br /><nowiki>
</nowiki>
}}
{{dp
|<nowiki>li_ion.ghg_by_energy</nowiki>
|<nowiki>73 kg / kWh</nowiki>
|<nowiki>Greenhouse gas emissions (CO2eq) of producing a lithium-ion battery</nowiki>
|<nowiki>"by energy" here means "by the size of the battery, defined by how much energy can be stored".</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
What is the environmental impact of lithium batteries? - Changeit ...</nowiki><br /><nowiki>
changeit.app › blog › 2021-03-26-environmental-impact-of-lithium-batteries </nowiki>
}}
}}
{{dp
{{dp
Line 171: Line 135:
"The average fuel economy for new 2020 model year cars, light trucks and SUVs in the United States was 25.4 miles per US gallon (9.3 L/100 km)."</nowiki><br /><nowiki>
"The average fuel economy for new 2020 model year cars, light trucks and SUVs in the United States was 25.4 miles per US gallon (9.3 L/100 km)."</nowiki><br /><nowiki>
- Fuel economy in automobiles - Wikipedia</nowiki>
- Fuel economy in automobiles - Wikipedia</nowiki>
}}
{{dp
|<nowiki>natural_gas_combined_cycle_power_plant.efficiency</nowiki>
|<nowiki>60%</nowiki>
|<nowiki>How much of the natural gas's heat energy becomes electricity, in an advanced "combined cycle" power plant</nowiki>
|<nowiki>This is considered a "maximum" value - the best natural gas power plants achieve this.</nowiki><br /><nowiki>
Simpler/older natural gas plants (no combined cycle) have only an efficiency of 33%, same as [coal_power_plant.efficiency].</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
Read more: https://energyeducation.ca/encyclopedia/Natural_gas_power_plant</nowiki>
}}
}}


''For a gasoline car {{light|(typical amount{{x|using US-based statistic for lack of other data}} of driving)}}:''
{{calc
|average_us_vehicle.mileage_by_time / car.fuel_economy * gasoline.ghg_by_energy
|tonnes/year
|usage_emissions_if_gasoline
}}


'''So far,''' we still haven't counted the environmental impact of ''making'' an electric car, which is significantly more than for a gasoline-powered car:


''For an EV charged by coal power plants {{light|(same amount of driving as above)}}:''
{{calc
|average_us_vehicle.mileage_by_time / electric_car.fuel_economy_equivalent * coal.ghg_by_energy / coal_power_plant.efficiency / (100% - power_grid.losses) / li_ion.charge_discharge_efficiency
|tonnes/year
|usage_emissions_if_ev_coal
}}


For simplicity sake, we're just going to count the emissions of making the batteries, and assume that making the rest of the car would take roughly the same emissions as making a gasoline-powered vehicle: {{x|Technically, the assumption is that the emissions ''divided by lifespan'' are about the same. Gasoline vehicles are more complex than batteryless EVs, but also have a longer lifespan.}}:


''Estimate for [[lithium-ion]] electric cars:''
''For an EV charged by natural gas power plants {{light|(same amount of driving)}}:''
{{calc
{{calc
|ev.battery * li_ion.ghg_by_energy / ev.lifespan
|average_us_vehicle.mileage_by_time / electric_car.fuel_economy_equivalent * (natural_gas.ghg_by_energy + natural_gas.fugitive_ghg_by_energy) / natural_gas_power_plant.efficiency / (100% - power_grid.losses) / li_ion.charge_discharge_efficiency
|tonnes / year
|tonnes/year
|battery_ghg
|usage_emissions_if_ev_natural_gas
}}
}}


''Now compare for the gasoline a non-electric car would burn, on average:''
 
''For an EV charged by ''advanced'' {{light|(combined-cycle type)}} natural gas power plants {{light|(same amount of driving)}}:
{{calc
{{calc
|gasoline.ghg_by_energy * average_us_vehicle.mileage_by_time / car.fuel_economy
|average_us_vehicle.mileage_by_time / electric_car.fuel_economy_equivalent * (natural_gas.ghg_by_energy + natural_gas.fugitive_ghg_by_energy) / natural_gas_combined_cycle_power_plant.efficiency / (100% - power_grid.losses) / li_ion.charge_discharge_efficiency
|tonnes / year
|tonnes/year
|gasoline_ghg
|usage_emissions_if_ev_advanced_natural_gas
}}
}}


''Now, for coal power plants charging EVs, same amount of driving:''
{{calc
|coal.ghg_by_energy * average_us_vehicle.mileage_by_time / fuel_economy_if_coal
|tonnes / year
|coal_ghg
}}


''Now, for advanced natural gas power plants charging EVs, same amount of driving:''
'''Battery emissions''' <!-- not technically a heading. we don't want mediawiki to generate a table of contents. -->
{{calc
 
|(natural_gas.ghg_by_energy + natural_gas.fugitive_ghg_by_energy) * average_us_vehicle.mileage_by_time / fuel_economy_if_advanced_natural_gas
So far, we still haven't counted the environmental impact of ''making'' an electric car, which is significantly more than for a gasoline-powered car.
|tonnes / year
 
|advanced_natural_gas_ghg
For simplicity sake, let's count the emissions of making the batteries, and assume that making the rest of the car would take roughly the same emissions as making a gasoline-powered vehicle: {{x|Technically, the assumption is that the emissions ''divided by lifespan'' are about the same. Gasoline vehicles are more complex than batteryless EVs, but also have a longer lifespan.}}:
 
{{dp
|<nowiki>ev.battery</nowiki>
|<nowiki>65.2 kWh</nowiki>
|<nowiki>Energy capacity of the average electric vehicle battery</nowiki>
|<nowiki>Useable battery capacity of full electric vehicles</nowiki><br /><nowiki>
https://ev-database.org/cheatsheet/useable-battery-capacity-electric-car</nowiki><br /><nowiki>
</nowiki>
}}
}}
 
{{dp
''Add the battery emissions:''
|<nowiki>li_ion.ghg_by_energy</nowiki>
{{calc
|<nowiki>73 kg / kWh</nowiki>
|battery_ghg + coal_ghg
|<nowiki>Greenhouse gas emissions (CO2eq) of producing a lithium-ion battery</nowiki>
|tonnes / year
|<nowiki>"by energy" here means "by the size of the battery, defined by how much energy can be stored".</nowiki><br /><nowiki>
|total_ghg_if_coal
</nowiki><br /><nowiki>
What is the environmental impact of lithium batteries? - Changeit ...</nowiki><br /><nowiki>
changeit.app › blog › 2021-03-26-environmental-impact-of-lithium-batteries </nowiki>
}}
}}
 
''For battery production:''
{{calc
{{calc
|battery_ghg + advanced_natural_gas_ghg
|ev.battery * li_ion.ghg_by_energy / ev.lifespan
|tonnes / year
|tonnes/year
|total_ghg_if_advanced_natural_gas
|battery_emissions
}}
}}


Line 223: Line 211:


'''''Now, for the final comparison:'''''
'''''Now, for the final comparison:'''''
{{calc
{{calc
|total_ghg_if_coal
|usage_emissions_if_ev_coal + battery_emissions
|% gasoline_ghg
|% usage_emissions_if_gasoline
}}
}}


{{calc
{{calc
|total_ghg_if_advanced_natural_gas
|usage_emissions_if_ev_natural_gas + battery_emissions
|% gasoline_ghg
|% usage_emissions_if_gasoline
}}
 
{{calc
|usage_emissions_if_ev_advanced_natural_gas + battery_emissions
|% usage_emissions_if_gasoline
}}
}}


Thus, with coal power, emissions are worse than driving a gasoline-powered car. But for ''advanced'' natural gas power plants, emissions are about half. In either case, this doesn't count the other environmental impacts {{light|(non-CO<sub>2</sub>)}} of mining lithium & cobalt.
Thus, with coal power, emissions are worse than driving a gasoline-powered car. But for ''advanced'' natural gas power plants, emissions are about half. In either case, this doesn't count the other environmental impacts {{light|(non-CO<sub>2</sub>)}} of mining lithium & cobalt.
<!-- TODO: redo this with more precision: coal.ghg_by_energy and natural_gas.ghg_by_energy? but then what about fugitive emissions? maybe make a datapoint "natural_gas.fugitive_ghg_by_energy" that factors it in -->


Maybe there would be a good case for fossil-fuel-electricity-powered vehicles if [[carbon capture and storage]] could be fully & safely applied to the power plants.
Maybe there would be a good case for fossil-fuel-electricity-powered vehicles if [[carbon capture and storage]] could be fully & safely applied to the power plants.


<!-- SCRAP: When that's factored in, there's probably no benefit to having an electric car in the coal-power scenario, and only ''moderate'' benefit in the advanced-natural-gas-power scenario. -->
<!--
<!--
  TALK: add scenario where fuel-cell vehicles are powered by hydrogen gas made from fossil fuels?
  TALK: add scenario where fuel-cell vehicles are powered by hydrogen gas made from fossil fuels?
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