5 ms·

It's a factor in arguments where people say "we don't need to just clean up electricity, we need to replace all fossil energy." They're usually referring to pri

It's a factor in arguments where people say "we don't need to just clean up electricity, we need to replace all fossil energy." They're usually referring to primary energy in these arguments. If you look at barrels of oil consumed per day in the US, then just plug the barrel-of-oil numbers into a unit converter to see how many terawatt hours it comes to, it looks hopeless to put a dent in oil consumption with electric vehicles and renewable electricity. But as the Bloomberg article points out, we don't need a 1:1 replacement of joules from fossil fuels with joules from non-fossil energy. If everyone currently driving a Toyota Corolla started driving a wind-charged battery electric vehicle instead, the total energy consumed would shrink dramatically without any behavioral changes. Most of the oil energy demanded by those Corollas is simply wasted as heat.

fuoqi 6y ago
But electricity is not 100% efficient either. At the very least you have transmission loss (to compensate for renewables intermittency you have to transfer energy farther), round-trip energy storage efficiency, EV efficiency. Also during cold weather you would have to spend electricity to heat car interior, while for gasoline cars this heat is "free". And don't forget that maintenance of renewable plants requires more energy, due to the low density of the exploited energy sources. In the very best scenario for vehicles you would get somewhere around 1:2 ratio, not even close to an order of magnitude.
- omgwtfbyobbq 6y ago
  That depends on the refined gasoline. Someplace like California, where petroleum is really heavy and needs a lot of energy to extract/refine, uses roughly 13kWh of natural gas, electricity, etc, to deliver one gallon of gas (page 5). https://ww2.arb.ca.gov/sites/default/files/classic//fuels/lcfs/ca-greet/lut-doc.pdf https://ww2.arb.ca.gov/sites/default/files/classic//fuels/lc... Most of that 13kWh is natural gas, so you can't use it directly in an EV. It can be used to generate electricity in a high efficiency natural gas power plant though, which would provide ~6-7kWh to consumers. By avoiding extraction/refining/transportation of petroleum and the associated natural gas/electricity used in those steps, we can instead use that to generate electricity, which would power an average EV at ~250Wh/mile roughly 25 miles. In places where petroleum doesn't need as much natural gas for extraction, that figure is lower, but the idea still applies.
- philipkglass 6y ago
  The 2018 Corolla has a combined driving cycle fuel consumption of 7.6 liters/100 km [1]. 7.6 liters of gasoline contains [2] 7.6 * 34.2 = 260 megajoules of primary energy. The standard Tesla Model 3 has a combined driving cycle electricity consumption of 16 kilowatt hours per 100 km [3]. 1 kWh is 3.6 megajoules, so it consumes 57.6 megajoules over 100 km. The Model 3 consumes 22% as much energy to travel the same distance as the Corolla. It's true that there are upstream energy losses before the BEV battery is charged up. About 5% [4] of generated electricity is lost to transmission and distribution in the United States. But there are also upstream energy losses before fuel goes into the Corolla's tank. The refining process that turns crude oil into motor fuel loses about 7% of primary energy along the way [5]. "Together the 96 EU mainstream refineries consume nearly 50 Mtoe total energy per year, which is equivalent to about 7% of their crude oil intake. This means that 93% of the energy content of the crude oil processed by the refinery is ultimately available in the refined products." [1] https://www.guideautoweb.com/en/makes/toyota/corolla/2018/specifications/ce-man/ https://www.guideautoweb.com/en/makes/toyota/corolla/2018/sp... [2] https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density [3] https://en.wikipedia.org/wiki/Tesla_Model_3 https://en.wikipedia.org/wiki/Tesla_Model_3 [4] https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 [5] https://www.concawe.eu/wp-content/uploads/2017/01/rpt_12-03-2012-01520-01-e.pdf https://www.concawe.eu/wp-content/uploads/2017/01/rpt_12-03-...
Steven_Vellon 6y ago
Bear in mind this cuts both ways. Replacing a gas heater (which directly produces thermal energy from chemical reaction) with an electric heater now means this energy has to be produced, transmitted, and run through a heating element. If this heater is being run at night, it likely has to go through an energy storage system, too.
- roywiggins 6y ago
  In many locations you can replace a resistive heater with a heat pump and more than make up for the losses.
- SuoDuanDao 6y ago
  heat pumps generally deliver three joules of heat per joule of electricity used to run them.

fuoqi 6y ago

But electricity is not 100% efficient either. At the very least you have transmission loss (to compensate for renewables intermittency you have to transfer energy farther), round-trip energy storage efficiency, EV efficiency. Also during cold weather you would have to spend electricity to heat car interior, while for gasoline cars this heat is "free". And don't forget that maintenance of renewable plants requires more energy, due to the low density of the exploited energy sources. In the very best scenario for vehicles you would get somewhere around 1:2 ratio, not even close to an order of magnitude.

omgwtfbyobbq 6y ago
That depends on the refined gasoline. Someplace like California, where petroleum is really heavy and needs a lot of energy to extract/refine, uses roughly 13kWh of natural gas, electricity, etc, to deliver one gallon of gas (page 5). https://ww2.arb.ca.gov/sites/default/files/classic//fuels/lcfs/ca-greet/lut-doc.pdf https://ww2.arb.ca.gov/sites/default/files/classic//fuels/lc... Most of that 13kWh is natural gas, so you can't use it directly in an EV. It can be used to generate electricity in a high efficiency natural gas power plant though, which would provide ~6-7kWh to consumers. By avoiding extraction/refining/transportation of petroleum and the associated natural gas/electricity used in those steps, we can instead use that to generate electricity, which would power an average EV at ~250Wh/mile roughly 25 miles. In places where petroleum doesn't need as much natural gas for extraction, that figure is lower, but the idea still applies.
philipkglass 6y ago
The 2018 Corolla has a combined driving cycle fuel consumption of 7.6 liters/100 km [1]. 7.6 liters of gasoline contains [2] 7.6 * 34.2 = 260 megajoules of primary energy. The standard Tesla Model 3 has a combined driving cycle electricity consumption of 16 kilowatt hours per 100 km [3]. 1 kWh is 3.6 megajoules, so it consumes 57.6 megajoules over 100 km. The Model 3 consumes 22% as much energy to travel the same distance as the Corolla. It's true that there are upstream energy losses before the BEV battery is charged up. About 5% [4] of generated electricity is lost to transmission and distribution in the United States. But there are also upstream energy losses before fuel goes into the Corolla's tank. The refining process that turns crude oil into motor fuel loses about 7% of primary energy along the way [5]. "Together the 96 EU mainstream refineries consume nearly 50 Mtoe total energy per year, which is equivalent to about 7% of their crude oil intake. This means that 93% of the energy content of the crude oil processed by the refinery is ultimately available in the refined products." [1] https://www.guideautoweb.com/en/makes/toyota/corolla/2018/specifications/ce-man/ https://www.guideautoweb.com/en/makes/toyota/corolla/2018/sp... [2] https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density [3] https://en.wikipedia.org/wiki/Tesla_Model_3 https://en.wikipedia.org/wiki/Tesla_Model_3 [4] https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 [5] https://www.concawe.eu/wp-content/uploads/2017/01/rpt_12-03-2012-01520-01-e.pdf https://www.concawe.eu/wp-content/uploads/2017/01/rpt_12-03-...

Steven_Vellon 6y ago

Bear in mind this cuts both ways. Replacing a gas heater (which directly produces thermal energy from chemical reaction) with an electric heater now means this energy has to be produced, transmitted, and run through a heating element. If this heater is being run at night, it likely has to go through an energy storage system, too.

roywiggins 6y ago
In many locations you can replace a resistive heater with a heat pump and more than make up for the losses.
SuoDuanDao 6y ago
heat pumps generally deliver three joules of heat per joule of electricity used to run them.