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.
- 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 [2] http://en.m.wikipedia.org/wiki/Gasoline_gallon_equivalent [3] http://www.eia.gov/energyexplained/index.cfm?page=electricit... [4] 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_terri...
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.
My Volt drives around 22 -> 28 miles on that power.
Eliminating gasoline refining would reduce the needed electricity by ~850 billion kWh / year, and the improved efficiency (ignoring charge/discharge cycle efficiency) would reduce the net energy to ~594 billion kWh / year - or 54 million average home PV installations. Quick googling shows that it will be about 10% higher for charging losses.
I think we agree ... that if there's less gas being refined, then there's less energy being used to do that ... if and only if gas refining is independent of refining into all the other products. If, on the other hand, refining into the other products efficiently ends up making gas anyway, then that's different.
Not a bad analysis, but there's a lot we're glossing over here.
For one thing, that 33kWh can get you about 100 miles in an average electric vehicle. That's compared to the average new US car which gets 25MPG, and existing cars out there average worse than that. So right away, there's a factor of four that we're leaving out here.
Further (as others have mentioned) it takes a huge amount of electricity to refine oil into gasoline. The electricity savings from not refining a gallon of gas are enough to drive an electric vehicle pretty far on its own.
Also, our grid and generating capacity are built to handle peak load, which (in most parts of the US) will occur on hot days when lots of people are using AC. On the flip side, the majority of electric car charging happens at night, so there's a lot of spare capacity already there.
If everyone switched to EVs, we'd probably need to build out more generating capacity, but probably not as much as your analysis suggests.
This isn't as much as you would think. The manufacturing electrical usage of the US (which includes this) is separated out on the EIA site, and you can simply subtract it :)
But these factors are absolutely enormous, particularly for the comparison you set up, as electric vehicles are about 3x as efficient. EVs on the mass market get about 3m/kWh, whereas most gas vehicles get about 1m/kWh, if you use your 33kWh/gal.
So instead of doubling US electricity consumption, 100% EV vehicle fleet just raises consumption by 33%, an amount that could nearly be made up for with simple efficiency gains in electricity use.
I subtracted out the electricity spent producing gas in the US, which isn't as much as one would think.
You can entirely ignore it if you want to compare the residential electric grid.
Note that if you stick to residential, it's 6x all current residential usage if everyone drives teslas and charges once a day.
[1] http://www.reddit.com/r/technology/comments/236uzj/toyota_co...
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Grand parent mentioned the grid, not the plants.
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.