What's the best way to charge millions of electric vehicles at once?

[Jim__]

From phys.org:

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(Phys.org)—About 350,000 plug-in electric vehicles (EVs) have been sold in the US from 2008—when they first entered the market—to mid-2015. Although EVs still represent a small fraction of the country's 250 million total vehicles, the continual increase in sales suggests that EVs will become even more popular over the next few decades. This raises the question of how millions of EVs may be charged at once on a grid that was not originally intended to supply such large amounts of power.

The main problem, as researchers Rui Carvalho and coauthors from the UK and Slovakia explain in a recent paper published in the New Journal of Physics, is congestion—not road traffic congestion, but charging traffic congestion. In their paper, they show that when the number of EVs being plugged into the network reaches a critical point, the system undergoes a phase transition from a "freeflow" state (where all vehicles can be fully charged within the expected time period, say 4 hours) to a congested state. In the congested state, some vehicles have to wait for increasingly long times to fully charge, resulting in queues of vehicles rapidly building up that will then face even longer charging times.

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In their paper, the researchers compared two charging strategies ("max-flow" and "proportional fairness&quot with the aim to guide network designers in deciding which algorithms to implement in the real world. Both algorithms investigated here rely on recent advances that combine tools from optimization and critical phenomena. As vehicles randomly plug in to the network, the network must continually solve the congestion control problem and allocate each vehicle an instantaneous power using the algorithm. The researchers compared the outcomes of both algorithms using simulations that are only possible due to techniques developed since 2012.

As the researchers explained, a good algorithm will have two features: it charges more vehicles at once, and it does so fairly, meaning all vehicles' charging times are roughly equal. As an example of unfairness, the "max-flow" algorithm charges vehicles closer to the main power source faster than those further away, which the researchers expect will not be socially acceptable. Fairness can be quantified by the Gini coefficient, which is traditionally used to measure income inequality. For comparison, the researchers note that Sweden has a Gini of 0.26, the US has a Gini of 0.41, and the Seychelles has the highest Gini of 0.66. The researchers explain that these values might provide a useful benchmark for identifying socially acceptable values for EV charging algorithms.

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[Erich Bloodaxe BSN]

1. Cats and balloons. Lots and lots of cats and balloons. nt

[Politicalboi]

2. Cars made of Graphene

With solar panels which is the roof, or the whole car could be a solar collector. Streets made of solar panels from graphene will power our cars in the future.

[packman]

3. I understand that potatos are good sources of electricity

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maybe a 50 lb. sack in the trunk?

[jtuck004]

7. Don't drive that through Texas. It would scare them to death...or maybe you. n/t

[DetlefK]

8. Actually, the potato is just there to prevent a short-circuit.

The real energy-source is that the electrodes consist of different metals. When the metals touch each other, electrons flow to bring the Fermi-levels into equilibrium. This would normally mean a short and high current at the plane where the metals touch, but the potato serves as a resistor and prolongs the current over a longer time.

EDIT: You can replace the potato with your body...

[krispos42]

4. At night, when domestic, commercial, and industrial demand is low.

Homes with solar panels on the roofs could also store power in a household battery, then pump that power into the car at night.

[AlbertCat]

5. What's the best way to charge millions of electric vehicles at once?

A credit card?

[hunter]

6. I've got the answer to that one.

Don't have millions of cars.

On the other hand, solar parking lot canopies are popping up all over the place in my community.

Charging a car at work seems like a great idea, and you get to park in the shade too.



http://cleantechnica.com/2010/08/03/solar-power-transforms-parking-lots-into-green-job-generators

But seriously, the best thing we could do is leave the automobile age behind us by creating communities in which private automobiles are entirely unnecessary.

[whatthehey]

9. I've got a walking range of 200 yds. How does your ideal community manage me?

I doubt even in Manhattan, which I can't afford, there's anywhere where I can live, work, shop and enjoy amenities within a 200 yd radius, and I can't do stairs.

That's the trouble with these granola wet-dream community fantasies. They're fine as long as everybody is young, fit, able bodied and has a job you can turn up to sweaty, mudsplashed or wet through from your bicycling/walking commute, and which does not expect you to take home and bring back files/laptops and whatnot.

[hunter]

10. I said no automobiles, not no vehicles.

The automobile age was once a fantasy, one that did not happen to end well.

Think of all the people who have been killed and maimed by automobiles, all the land that's been paved over, the air pollution, the greenhouse gasses... it's not a pretty picture. I am a very strong supporter of "handicap accessible" architecture and parking spaces, for a number of personal reasons.

So, somebody has got to imagine a better future, right?

I posted two alternatives in my post, no? Walkable communities (which might include any number of smaller electric vehicles and assistive technologies), and more conventionally, electric cars parked under solar awnings.

I'm not advocating a return to the horse and buggy days.

[Shankapotomus]

11. Until renewable power generation eclipses traditional,

the same way we power millions of cars now - fossil fuels. Instead of those fossil fuels going directly into cars, they would simply go to central power plants to produce more electricity for the grid.

Cars could also carry portable, thin film solar arrays that could be deployed on sunny days to ease the pressure on the grid and trickle charge cars with enough power to get them home.

As more renewable and efficient power generation comes online to handle our electric needs, we could then start eliminating fossil fuel use.

As far as power allocation at the charging point, I like the proposal presented in the article.

An additional way to reduce charging congestion is for vehicles that do not have a long commute home, to punch in only the amount of charge needed to get them home. Once the charging port has supplied that vehicle with maybe a little over what would be needed to get them home, the supply of electricity could be cut off from that car, allowing other cars to move up more quickly in the charging queue.