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If you charge an [[electric vehicles|electric car]] with electricity that was generated by [[fossil fuels]], is it '''as bad''' for the environment as driving a gas car?
If you charge an [[electric vehicles|electric car]] with electricity that was generated by [[fossil fuels]], is it '''as bad''' for the environment as driving a gas car?


Short answer: '''Yes.'''
==Short answer==
<big>'''Yes.'''</big>


Long answer:
The carbon emissions, compared to a gasoline car, are approximately:
* 135% for coal power plants
* 89% for ''older'' natural gas power plants {{light|(more common)}}
* 56% for ''newer'' natural gas power plants {{light|(less common)}}


==Long answer==
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. -->


''For coal power plants:''
{{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>
Line 32: Line 45:
|<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 40: Line 59:
|<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>
Line 46: Line 65:
- Fuel economy in automobiles - Wikipedia</nowiki>
- Fuel economy in automobiles - Wikipedia</nowiki>
}}
}}
{{dp
|<nowiki>coal.ghg_by_energy</nowiki>
|<nowiki>95.35 kg / million btu</nowiki>
|<nowiki>CO2 emissions of burning coal</nowiki>
|<nowiki>https://www.eia.gov/environment/emissions/co2_vol_mass.php</nowiki>
}}
{{dp
|<nowiki>gasoline.ghg_by_energy</nowiki>
|<nowiki>71.30 kg / million btu</nowiki>
|<nowiki>CO2 emissions of burning gasoline</nowiki>
|<nowiki>https://www.eia.gov/environment/emissions/co2_vol_mass.php</nowiki>
}}
{{dp
|<nowiki>usa.natural_gas.fugitive_ghg</nowiki>
|<nowiki>176.1 million tonnes / year</nowiki>
|<nowiki>Greenhouse gas CO2eq of fugitive methane leaks from all natural gas infrastructure in the USA</nowiki>
|<nowiki>Environmental Protection Agency (EPA)</nowiki><br /><nowiki>
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014</nowiki><br /><nowiki>
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014</nowiki><br /><nowiki>
2016 Complete Report (PDF)</nowiki><br /><nowiki>
Using data from 2014</nowiki>
}}
{{dp
|<nowiki>usa.natural_gas.energy</nowiki>
|<nowiki>27.9 quadrillion btu / year</nowiki>
|<nowiki>U.S. energy consumption from natural gas combustion only</nowiki>
|<nowiki>Environmental Protection Agency (EPA)</nowiki><br /><nowiki>
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014</nowiki><br /><nowiki>
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014</nowiki><br /><nowiki>
2016 Complete Report (PDF)</nowiki><br /><nowiki>
Datapoint was found on page 115, from pie chart and line graph, using data from 2014</nowiki>
}}
{{dp
|<nowiki>natural_gas.fugitive_ghg_by_energy</nowiki>
|<nowiki>usa.natural_gas.fugitive_ghg / usa.natural_gas.energy</nowiki>
|<nowiki>Fugitive emissions (CO2eq) of natural gas, per unit energy</nowiki>
|<nowiki>Average based on US datapoints.</nowiki>
}}
{{dp
|<nowiki>natural_gas.ghg_by_energy</nowiki>
|<nowiki>53.07 kg / million btu</nowiki>
|<nowiki>CO2 emissions of burning natural gas</nowiki>
|<nowiki>Does not include the fugitive methane emissions from unburned fuel. Those vary by how the gas is burned.</nowiki><br /><nowiki>
</nowiki><br /><nowiki>
https://www.eia.gov/environment/emissions/co2_vol_mass.php</nowiki>
}}
{{dp
|<nowiki>ev.lifespan</nowiki>
|<nowiki>8 years</nowiki>
|<nowiki>Expected lifespan of an electric vehicle</nowiki>
|<nowiki>Batteries usually are the component that wears out first.</nowiki>
}}
{{dp
|<nowiki>average_us_vehicle.mileage_by_time</nowiki>
|<nowiki>32 miles/day</nowiki>
|<nowiki>Distance driven by the average American vehicle</nowiki>
|<nowiki>Top Numbers Driving America's Gasoline Demand</nowiki><br /><nowiki>
https://www.api.org/news-policy-and-issues/blog/2022/05/26/top-numbers-driving-americas-gasoline-demand</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 usage)}}:
{{calc
|average_us_vehicle.mileage_by_time / car.fuel_economy * gasoline.ghg_by_energy
|tonnes/year
|usage_emissions_if_gasoline_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 an EV charged by '''natural gas''' power plants'' {{light|(same amount of driving)}}:
{{calc
|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
|usage_emissions_if_EV_natural_gas
}}
''For an EV charged by advanced {{light|(combined-cycle type)}} natural gas power plants'' {{light|(same amount of driving)}}:
{{calc
{{calc
|electric_car.efficiency * li_ion.charge_discharge_efficiency * (100% - power_grid.losses) * coal_power_plant.efficiency
|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
|car.fuel_economy
|tonnes/year
|usage_emissions_if_EV_advanced_natural_gas
}}
}}


In other words, there's a ''very slight'' increase in overall fuel efficiency, but it's not much.


'''Battery production emissions''' <!-- not technically a heading. we don't want mediawiki to generate a table of contents. -->


''For natural gas power plants'':
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.


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 (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.}}
For simplicity sake, let's assume that ''batteries'' account for the entire difference between electric cars and gasoline cars, in terms of GHG emissions of ''production'' divided by vehicle ''lifespan''. {{x|A gasoline vehicle is a bit more complex than a batteryless EV, but the former also has a longer lifespan.}}


''Other'' natural gas power plants (the more advanced "combined-cycle" type) are more efficient: up to 60%:
{{dp
{{dp
|<nowiki>natural_gas_combined_cycle_power_plant.efficiency</nowiki>
|<nowiki>ev.battery</nowiki>
|<nowiki>60%</nowiki>
|<nowiki>65.2 kWh</nowiki>
|<nowiki>How much of the natural gas's heat energy becomes electricity, in an advanced "combined cycle" power plant</nowiki>
|<nowiki>Energy capacity of the average electric vehicle battery</nowiki>
|<nowiki>This is considered a "maximum" value - the best natural gas power plants achieve this.</nowiki><br /><nowiki>
|<nowiki>Useable battery capacity of full electric vehicles</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>
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>
</nowiki><br /><nowiki>
Read more: https://energyeducation.ca/encyclopedia/Natural_gas_power_plant</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
|ev.battery * li_ion.ghg_by_energy / ev.lifespan
|tonnes/year
|battery_emissions
}}
 
 
 
'''''Now, for the final comparison:'''''
{{calc
|usage_emissions_if_EV_coal + battery_emissions
|% usage_emissions_if_gasoline_car
}}
}}
{{calc
{{calc
|electric_car.efficiency * li_ion.charge_discharge_efficiency * (100% - power_grid.losses) * natural_gas_combined_cycle_power_plant.efficiency
|usage_emissions_if_EV_natural_gas + battery_emissions
|car.fuel_economy
|% usage_emissions_if_gasoline_car
}}
}}


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.
{{calc
|usage_emissions_if_EV_advanced_natural_gas + battery_emissions
|% usage_emissions_if_gasoline_car
}}


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.


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.{{qn}}
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.
* Note: This varies by the ''type'' of batteries used.<!-- TODO: bring in data from other pages?: energy to manufacture batteries; minerals involved -->


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?

Latest revision as of 22:12, 15 October 2023

If you charge an electric car with electricity that was generated by fossil fuels, is it as bad for the environment as driving a gas car?

Short answer

Yes.

The carbon emissions, compared to a gasoline car, are approximately:

  • 135% for coal power plants
  • 89% for older natural gas power plants (more common)
  • 56% for newer natural gas power plants (less common)

Long answer

The following calculations compare the average gasoline-powered vehicle with the average lithium-ion battery-based electric vehicle. Greenhouse gas emissions are in tonnes CO2 equivalent (CO2eq):


Usage emissions

electric_car.fuel_economy_equivalent
100 miles per 34.6 kWh
The "gas mileage" equivalent for an average electric car.
Average Electric Car kWh Per Mile [Results From 231 EVs]
ecocostsavings.com › average-electric-car-kwh-per-mile
li_ion.charge_discharge_efficiency
85%
When you charge a lithium-ion battery, this much of the energy can be recovered. The rest is lost as heat.
Range: 80 to 90 %
from wikipedia; haven't found original source yet
power_grid.losses
5%
Electricity lost in transmission & distribution
Frequently Asked Questions (FAQs) - U.S. Energy Information ... - EIA
www.eia.gov › tools › faqs › faq
Nov 4, 2021 · "The U.S. Energy Information Administration (EIA) estimates that electricity transmission and distribution (T&D) losses equaled about 5% of ..."
coal_power_plant.efficiency
33%
How much of the coal's combustion heat energy becomes electricity
Transformative Power Systems | Department of Energy
https://www.energy.gov/fecm/transformative-power-systems
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.
car.fuel_economy
25.4 miles per gallon gasoline
Gas mileage of an average American new car
This datapoint is conformable with [electric_car.fuel_economy_equivalent], because the calculator understands 'gallon gasoline' as an energy unit.

Citation:
"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)."
- Fuel economy in automobiles - Wikipedia
coal.ghg_by_energy
95.35 kg / million btu
CO2 emissions of burning coal
https://www.eia.gov/environment/emissions/co2_vol_mass.php
gasoline.ghg_by_energy
71.30 kg / million btu
CO2 emissions of burning gasoline
https://www.eia.gov/environment/emissions/co2_vol_mass.php
usa.natural_gas.fugitive_ghg
176.1 million tonnes / year
Greenhouse gas CO2eq of fugitive methane leaks from all natural gas infrastructure in the USA
Environmental Protection Agency (EPA)
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014
2016 Complete Report (PDF)
Using data from 2014
usa.natural_gas.energy
27.9 quadrillion btu / year
U.S. energy consumption from natural gas combustion only
Environmental Protection Agency (EPA)
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014
2016 Complete Report (PDF)
Datapoint was found on page 115, from pie chart and line graph, using data from 2014
natural_gas.fugitive_ghg_by_energy
usa.natural_gas.fugitive_ghg / usa.natural_gas.energy
Fugitive emissions (CO2eq) of natural gas, per unit energy
Average based on US datapoints.
natural_gas.ghg_by_energy
53.07 kg / million btu
CO2 emissions of burning natural gas
Does not include the fugitive methane emissions from unburned fuel. Those vary by how the gas is burned.

https://www.eia.gov/environment/emissions/co2_vol_mass.php
ev.lifespan
8 years
Expected lifespan of an electric vehicle
Batteries usually are the component that wears out first.
average_us_vehicle.mileage_by_time
32 miles/day
Distance driven by the average American vehicle
Top Numbers Driving America's Gasoline Demand
https://www.api.org/news-policy-and-issues/blog/2022/05/26/top-numbers-driving-americas-gasoline-demand
natural_gas_combined_cycle_power_plant.efficiency
60%
How much of the natural gas's heat energy becomes electricity, in an advanced "combined cycle" power plant
This is considered a "maximum" value - the best natural gas power plants achieve this.
Simpler/older natural gas plants (no combined cycle) have only an efficiency of 33%, same as [coal_power_plant.efficiency].

Read more: https://energyeducation.ca/encyclopedia/Natural_gas_power_plant

For a gasoline car (typical usage): average_us_vehicle.mileage_by_time / car.fuel_economy * gasoline.ghg_by_energy tonnes/year usage_emissions_if_gasoline_car (calculation loading)


For an EV charged by coal power plants (same amount of driving as above): 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 (calculation loading)


For an EV charged by natural gas power plants (same amount of driving): 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 usage_emissions_if_EV_natural_gas (calculation loading)


For an EV charged by advanced (combined-cycle type) natural gas power plants (same amount of driving): 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 usage_emissions_if_EV_advanced_natural_gas (calculation loading)


Battery production emissions

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 simplicity sake, let's assume that batteries account for the entire difference between electric cars and gasoline cars, in terms of GHG emissions of production divided by vehicle lifespan. (...)( A gasoline vehicle is a bit more complex than a batteryless EV, but the former also has a longer lifespan. )

ev.battery
65.2 kWh
Energy capacity of the average electric vehicle battery
Useable battery capacity of full electric vehicles
https://ev-database.org/cheatsheet/useable-battery-capacity-electric-car
li_ion.ghg_by_energy
73 kg / kWh
Greenhouse gas emissions (CO2eq) of producing a lithium-ion battery
"by energy" here means "by the size of the battery, defined by how much energy can be stored".

What is the environmental impact of lithium batteries? - Changeit ...
changeit.app › blog › 2021-03-26-environmental-impact-of-lithium-batteries

For battery production: ev.battery * li_ion.ghg_by_energy / ev.lifespan tonnes/year battery_emissions (calculation loading)


Now, for the final comparison: usage_emissions_if_EV_coal + battery_emissions % usage_emissions_if_gasoline_car (calculation loading)

usage_emissions_if_EV_natural_gas + battery_emissions % usage_emissions_if_gasoline_car (calculation loading)

usage_emissions_if_EV_advanced_natural_gas + battery_emissions % usage_emissions_if_gasoline_car (calculation loading)

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 (non-CO2) of mining lithium & cobalt.

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.

See also

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