Electric vehicles – mileage and required infrastructure

ResearchBlogging.org These days are all about electric cars. Yesterday I wrote about the “smart chargers” that help electric cars determine the optimal time to charge to reduce grid load and prices. Today, I bring you two interesting scientific papers and one equally interesting piece of techno-journalism.

In an Energy Policy article with the cumbersome title “Integrating private transport into renewable energy policy: The strategy of creating intelligent recharging grids for electric vehicles”, the authors describe a model for solving two problems with one single integrated systems solution. The first deals with stability problems that arise with the introduction of more renewable energy: wind, solar and other renewables are not consistent in their electricity output [1]. The second problem is reducing CO2 emissions from the transport sector. By switching to electric vehicles (EVs), both these problems can be solved if what the authors dub the Electric Recharge Grid Operator (ERGO [2]) can be implemented. The idea is that EVs can be used as large portable batteries that supply electricity to the grid when not in use, thus evening out the spikes and valleys in renewable electricity production.

I’ll leave it to Andersen, Mathews and Rask themselves to explain it. From the abstract:

The ERGO business model effectively solves both problems, by transforming EVs into distributed storage devices for electricity, thus enabling a fresh approach to evening out of fluctuating and unpredictable energy sources, while drastically reducing green house gas emissions. This integrated solution carries many other associated benefits, amongst which are the possibility of introducing vehicle-to-grid (V2G) distributed power generation; introducing IT intelligence to the grid, and creating virtual power plants from distributed sources; and providing new applications for carbon credits in the decarbonisation of the economy.

Amazingly, several countries have already signed on to implement this the coming years. It’ll be interesting to see how it plays out.

Of course, the proposition is not without its problems. The most important one is that the whole things relies on the introduction of a “nationwide infrastructure of charging stations where EVs’ batteries may be charged (or replaced) easily and quickly.” This is easier said than done. The authors hope a new private initiative could provide pre-existing solutions so that the thing may get off the ground, but I have some serious doubts regarding that. Making big changes to infrastructure is not easily done without large involvement from the public sector. Similarly, they propose decoupling battery ownership from car ownership, so that batteries are leased rather than owned by drivers. This will facilitate frequent changing and charging batteries at designated charging stations similar to today’s gas stations. This actually requires a change in the design of modern EVs, as they are not set up for easy, on-the-spot battery changing.

All in all, it all sounds very good, but also insanely ambitious.

Speaking of vehicles and ambitions, a different Energy Policy article has tried to measure the fuel efficiency of US cars since 1923 (!) to today. The article, titled “Fuel efficiency of vehicles on US roads:1923–2006” is brief (3 pages), but interesting. It seems that fuel efficiency actually went down until about 1970, probably due to cars getting larger and heavier, and then quickly increased a lot until the improvement slowed down considerably around 1990. Does this mean that the auto industry has reached its potential when it comes to miles per gallon, or is there something else going on here? Of course, these findings must be taken with a grain of salt. A lot of the early numbers are based on estimates of all involved parameters: number of cars on the road, kinds of vehicles, number of miles driven, amount of fuel used. But from the 70s on, the numbers seem better.

Anyway, this brings me full circle to the topic of electric vehicles. An interesting article in Wired details how new plug-in hybrids are more fuel efficient than regular cars, getting more miles for the gallon. This might sound obvious, since they partly run on electricity (and that electricity must come from somewhere), but the question is more how much is gained. Seems like the gain in efficiency is less than the industry has touted. The industry claims that this is because people don’t drive the cars correctly, but that sounds like a weak excuse. Firstly, because with “correct” driving, normal fuel cars could go much farther too, and secondly, because measuring fuel efficiency should be based on real life situations and not desert test tracks. That being said, the new plug-ins still improve on both older hybrids and even older all-fuel cars.

[1] One interesting discussion of this regarding wind can be found here.
[2] Cleverly also the Latin word for “energy”.


Andersen, P., Mathews, J., & Rask, M. (2009). Integrating private transport into renewable energy policy: The strategy of creating intelligent recharging grids for electric vehicles Energy Policy, 37 (7), 2481-2486 DOI: 10.1016/j.enpol.2009.03.032

Sivak, M., & Tsimhoni, O. (2009). Fuel efficiency of vehicles on US roads: 1923–2006 Energy Policy DOI: 10.1016/j.enpol.2009.04.001


7 Responses

  1. It really seems like a Rube Goldberg type solution, with mixed results. Sure, the power transfer equipment would already be in place. But there are all these millions of extra batteries that everyone has to lug around everywhere. Why not just put some extra large batteries in the ground by the charging stations?

    I’m a bit behind on battery technology. I was of the impression that recharging a battery was somewhat time intensive still, though improvements have been made. Yet it seems we’re still using the modern gas station as our model. For longer charges, I would thing secure stations at home and office would be preferable. How long can one go on a 5 minute charge nowadays?

  2. If I’m not mistaken, a full charge is still a matter of a couple of hours at the least. With a full-battery range of about 120 km and assuming power use is evenly distributed, a five-minute charge should give you 5 km of driving. Not a lot. Charging times are a real headache for the EV business, especially if one plans to go by existing infrastructure.

    Maybe the financial crisis can be used for some intensive investment in infrastructure, like the Great Depression was used for building the US Interstate system?

  3. […] View original post here: Electric vehicles – mileage and required infrastructure « STS guru … […]

  4. Interesting information, hope to visit again…

  5. I noticed that this is not the first time at all that you mention this topic. Why have you decided to touch it again?
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  7. Hey, I really appreciated your comments above.

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