Electric Cars, Trucks and Semis - Is It Time for Nuclear?
Hybrid electric cars are being pointed to as the next generation of transport in the US yet skepticism about their effectiveness remains. The main question I'm curious about is whether, in the long run, hydrocarbon fuels or electric power would be the cheaper source of fuel for vehicles.
BREAK OUT THE MATH!
To maintain a constant speed a vehicle must be accelerating with a force equal to the friction/drag pushing back. I'll need to calculate the normal force (Fn=Fg), and the rolling friction force (f=µk•Fn).
For simplicity's sake I'll ignore all wind resistance. This isn't good if you're trying to figure out the force on a light car, but the heavier your vehicles the more and more insignificant wind resistance will become.
First I looked up the number of miles traveled by passenger cars in the United States. These numbers are published by the Department of Transportation here and my work has been attached bellow. I used 2002 numbers because I could only find data regarding commercial freight vehicles for 2002 and I wanted the numbers to be cronologically consistant..
Average Car: 3000 lbs or 1361 kgs
Rolling Coefficent Per Tire: 0.03 (source Wikipedia, results would scale directly to a correction)
Kilometers Total Excluding Trucks: 4.1 Trillion Kilometers
Total Load on Electric Grid: 0.456 Tera Watt Hours
YEESH Sounds bad. But then again we could increase the capacity of our electric system to compensate. In 2002 the US generated 3.8 TWhs of electricity. To compensate for all-electric passenger cars we would only need to increase our electric capacity by 11.80% in 2002.
Lets assume we can do that. Did we eliminate our dependency on conventional fuels? Maybe not. Not all cars are 3000 lbs and not all vehicles are cars. Commercial trucks make up a good chunk of our transportation network and per capita they drive farther and use more gas than the average passenger vehicle.
The department of transportation also published numbers on freight vehicles mileage and weight here. Using the median (or in the case of the heaviest vehicles the minimum) weight and mileage I calculated the amount of energy spent by commercial vehicles in 2002. Since the numbers differed from weight class to weight class I'll just post the totals:
Total Load on Electric Grid: 0.466 TWHS
This would require a separate 12.07% increase in our capacity for a grand total 23.87% increase for both commercial and private vehicles . All the spreadsheets used are attached bellow for review.
There are obviously several assumptions in all this math. Firstly I'm assuming electric motors and batteries are 100% efficient. In a pure energy sense electric motors are far more efficient than their combustion counterparts, but even so there will be loss which is not accounted for in these calculations. Wind resistance, idle time, stop and go effects and other factors were also not considered. In this conceptual world a car is simply moving at a constant speed without stopping for all the miles it drives on perfectly smooth asphault.
I'm also ignoring cost to manufacture, maintain, and replace the electric drive systems or the full cost of ownership over a 10-15 year lifetime for a car. There are also logistical issues with charging a car or truck. For one there are grid balancing issues which are tough to overcome (imagine every car charging up at the end of rush-hour and the resulting spike in demand). Also, you will no longer will you be able to just 'fill up' and go along on your way whether you're a semi truck or a minivan; this is usually addressed with on-board generators or a second drive but that can add a lot of weight to a commuter car. Finally, surplusses of fuel will be a thing of the past as it would be next to impossible to store up electricity reserves. However that was never the concern of this article, it was merely a question of whether or not the capacity of the electric grid could handle a transition to all electric vehicles.
So nearly 1 TWH of extra electricity!?! Sounds like a lot right? Well, not really, as long as you're willing to go nuclear. Modern nuclear plants have capacities in the 1 GW range and more realistically run in the 500 MW range. So lets just build 1 nuclear plant and see if we can handle every car and commercial vehicle in America:
500 MW * 365 days * 24 hours/day = 4.38 TWHs.
Woops, did we just double our electric capacity? In short, YES and that's just with one nuclear plant; many bills opting for new nuclear plants suggest building 20 or more. This would not only solve our land-transportation energy issues, but also our home energy costs (electric cooling and heating would be trivially cheap for even the poorest communities). On top of that this would buy us time to properly build up 100% renewable systems like solar, wind and fission power and in the meantime leaving us C02 emission free.
The unfortunate side of this debate is that these two arguments are rarely shared popitically. Nuclear power is shunned by democrats (even by the Obamster) but held high by republicans and republicans rarely argue that we should go all electric with our transportation industry.
Personally, I think the transition time and cost will still be great enough that conventional fuels will still rule our economy. Also alternative hydrocarbon fuels are being developed from algae and a fungus that excretes diesel fuel that would not only produce viable amounts of fuel but also done in such a way that it doesn't tax our food supply. Electric cars are viable in terms of capacity on the grid, but I personally can't wait for people to start dumping their McClaren's and Shelby Mustangs on the market to better afford their Tesla replacements.