8 ms·

Has there been any analysis on the amount of joule energy pumped out of all of the current gas stations on a daily basis? I'm worried the current electric grid

by snarfy 12y ago

Has there been any analysis on the amount of joule energy pumped out of all of the current gas stations on a daily basis? I'm worried the current electric grid is woefully insufficient for a world full of electric cars. I know their are plenty of electric lines out there running at greater than 100% of their rated capacity already.

azunds 12y ago
With current pv technology this probably will not be a problem
- jacquesm 12y ago
  What technology generates the current has nothing to do with whether or the GPs concerns are valid. It's all about transportation, not just generation. Grand parent mentioned the grid, not the plants.
  - erikpukinskis 12y ago
    You need a lot less grid if you're generating power on the roof of the building you park your car in.
    - jacquesm 12y ago
      Do the math. It will not work. Sunlight in full sun with the sun at 90 degrees relative to the panels, in winter (cool panels) will give you about 200 watts / square meter of surface of electricity at the exit of the inverter. You'll need a little bit less grid, definitely not a lot. Those buildings are typically multi-layer and don't have a roof over the top layer (though not always) so it's not a trivial modification either. You could design that in from day 1 of course and it will help a little bit but that's borderline making money rather than a significant reduction in infrastructure. Say your carpark is 100 meters long and 30 meters wide, that will house 50x4x4 = 800 cars to charge but you're collecting (on a good day) no more than 100x30x200 = 600 KW. It's not nothing, but if you take into account that a single normal car charger is already 3 KW to charge a full park of such cars would require 2.4 MW. And that's the slowest rate of charge for those cars, go faster and the requirements shoot up. Best case with only 4 decks of cars you're looking at a 25% reduction. Worst case not more than 10%. Good but not great. The grid is definitely going to see some structural modifications before we can push the equivalent of our current gasoline consumption through it.
cgearhart 12y ago
Napkin math supports your concerns. - The US used 134.51 billion gallons of gas in 2013.[1] - There are ~33 kWh/gal in gasoline [2] 134.51e9 gal x 33 kWh / gal = 4.44e12 kWh (4.44 trillion kWh / year) - The US used a total of 3.856 trillion kWh of electricity in 2011 [3] Ignoring improved efficiency and excluding other factors, converting all gasoline usage to electric would more than double US electricity consumption. Under reasonable assumptions, PV solar generates about 0.75 kWh/m^2 per day. [4] 4.44 trillion kWh/year / 0.75 kWh/m^2 per day x 365 days/year / 1e6 m^2 per km^2 = 16,219 km^2 Which means you could generate all of the required electricity with about 16,200 km^2 of solar panels - which is just about exactly the total land area of Hawaii [5], or 405 million average home PV systems. It's doable, but it will be non-trivial. [1] http://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10 http://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10 [2] http://en.m.wikipedia.org/wiki/Gasoline_gallon_equivalent http://en.m.wikipedia.org/wiki/Gasoline_gallon_equivalent [3] http://www.eia.gov/energyexplained/index.cfm?page=electricity_use http://www.eia.gov/energyexplained/index.cfm?page=electricit... [4] http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/ http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-eff... [5] http://en.m.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area http://en.m.wikipedia.org/wiki/List_of_U.S._states_and_terri...
- johnward 12y ago
  If I read this right this is assuming that all current gasoline usage is converted into electrical usage. It's not like that would happen over night though, or possibly ever. Also, can PV help at night when a majority of charging should occur?
  - cgearhart 12y ago
    You are correct - it assumes total conversion, but the numbers don't change if you project some ramp for the transition. A more reasonable assumption for charging is that it will take place wherever electric vehicles are parked, regardless of time of day; in that case, large parking lot installations for PV may be more sensible than individual home systems. In either case, it seems likely that increased adoption of electric vehicles will change what we consider "peak" electricity use hours, since it could consume half or more of total electricity in the US.
johnward 12y ago
My assumption is that most of the charging for electric vehicles (aside from stopping at a supercharger) will go on at night which is off peak for our grid now. At least for the short term future. I don't know that solar will help in that case. The adoption of electric vehicles seems to be slow enough that it should give us time to identify the problems and attempt to come up with solutions. That rate could significantly increase if the model 3 delivers on it's promises. It probably still take major investments in our electrical infrastructure to support a majority of vehicles becoming electric.
ohitsdom 12y ago
It'd be interesting to see, but it's going to be a LONG time before even 10% of the vehicles on the road are electric.
BrandonMarc 12y ago
Is this where a Solar City type of setup would come into play? Tesla's charging stations generating their own electricity, thank you very much, partnered with SC. Or would that be feasible? Of course, Tesla could also use vertical windmills [1], geothermal, etc at its stations. I'm a big fan of distributed generation; that makes the electric grid's shortcomings a moot point. ----- [1] http://www.quietrevolution.com/qr5/faqs-qr5-turbine.htm http://www.quietrevolution.com/qr5/faqs-qr5-turbine.htm
zurn 12y ago
The electricity grid is not a static thing, it is upgraded according to demand. Demand doesn't change overnight.

by snarfy 12y ago

azunds 12y ago

With current pv technology this probably will not be a problem

jacquesm 12y ago
What technology generates the current has nothing to do with whether or the GPs concerns are valid. It's all about transportation, not just generation. Grand parent mentioned the grid, not the plants.
- erikpukinskis 12y ago
  You need a lot less grid if you're generating power on the roof of the building you park your car in.
  - jacquesm 12y ago
    Do the math. It will not work. Sunlight in full sun with the sun at 90 degrees relative to the panels, in winter (cool panels) will give you about 200 watts / square meter of surface of electricity at the exit of the inverter. You'll need a little bit less grid, definitely not a lot. Those buildings are typically multi-layer and don't have a roof over the top layer (though not always) so it's not a trivial modification either. You could design that in from day 1 of course and it will help a little bit but that's borderline making money rather than a significant reduction in infrastructure. Say your carpark is 100 meters long and 30 meters wide, that will house 50x4x4 = 800 cars to charge but you're collecting (on a good day) no more than 100x30x200 = 600 KW. It's not nothing, but if you take into account that a single normal car charger is already 3 KW to charge a full park of such cars would require 2.4 MW. And that's the slowest rate of charge for those cars, go faster and the requirements shoot up. Best case with only 4 decks of cars you're looking at a 25% reduction. Worst case not more than 10%. Good but not great. The grid is definitely going to see some structural modifications before we can push the equivalent of our current gasoline consumption through it.

cgearhart 12y ago

Napkin math supports your concerns. - The US used 134.51 billion gallons of gas in 2013.[1] - There are ~33 kWh/gal in gasoline [2] 134.51e9 gal x 33 kWh / gal = 4.44e12 kWh (4.44 trillion kWh / year) - The US used a total of 3.856 trillion kWh of electricity in 2011 [3] Ignoring improved efficiency and excluding other factors, converting all gasoline usage to electric would more than double US electricity consumption. Under reasonable assumptions, PV solar generates about 0.75 kWh/m^2 per day. [4] 4.44 trillion kWh/year / 0.75 kWh/m^2 per day x 365 days/year / 1e6 m^2 per km^2 = 16,219 km^2 Which means you could generate all of the required electricity with about 16,200 km^2 of solar panels - which is just about exactly the total land area of Hawaii [5], or 405 million average home PV systems. It's doable, but it will be non-trivial. [1] http://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10 http://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10 [2] http://en.m.wikipedia.org/wiki/Gasoline_gallon_equivalent http://en.m.wikipedia.org/wiki/Gasoline_gallon_equivalent [3] http://www.eia.gov/energyexplained/index.cfm?page=electricity_use http://www.eia.gov/energyexplained/index.cfm?page=electricit... [4] http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/ http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-eff... [5] http://en.m.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area http://en.m.wikipedia.org/wiki/List_of_U.S._states_and_terri...

johnward 12y ago
If I read this right this is assuming that all current gasoline usage is converted into electrical usage. It's not like that would happen over night though, or possibly ever. Also, can PV help at night when a majority of charging should occur?
- cgearhart 12y ago
  You are correct - it assumes total conversion, but the numbers don't change if you project some ramp for the transition. A more reasonable assumption for charging is that it will take place wherever electric vehicles are parked, regardless of time of day; in that case, large parking lot installations for PV may be more sensible than individual home systems. In either case, it seems likely that increased adoption of electric vehicles will change what we consider "peak" electricity use hours, since it could consume half or more of total electricity in the US.

johnward 12y ago

My assumption is that most of the charging for electric vehicles (aside from stopping at a supercharger) will go on at night which is off peak for our grid now. At least for the short term future. I don't know that solar will help in that case. The adoption of electric vehicles seems to be slow enough that it should give us time to identify the problems and attempt to come up with solutions. That rate could significantly increase if the model 3 delivers on it's promises. It probably still take major investments in our electrical infrastructure to support a majority of vehicles becoming electric.

ohitsdom 12y ago

It'd be interesting to see, but it's going to be a LONG time before even 10% of the vehicles on the road are electric.

BrandonMarc 12y ago

Is this where a Solar City type of setup would come into play? Tesla's charging stations generating their own electricity, thank you very much, partnered with SC. Or would that be feasible? Of course, Tesla could also use vertical windmills [1], geothermal, etc at its stations. I'm a big fan of distributed generation; that makes the electric grid's shortcomings a moot point. ----- [1] http://www.quietrevolution.com/qr5/faqs-qr5-turbine.htm http://www.quietrevolution.com/qr5/faqs-qr5-turbine.htm

zurn 12y ago

The electricity grid is not a static thing, it is upgraded according to demand. Demand doesn't change overnight.