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Plugless Power: Will Inductive Charging Change the Game for EVs?

Yesterday at the Silicon Valley Driving Charged & Connected EV symposium at SAP in Palo Alto I had the opportunity to witness plugless charging, in which an electric vehicle drives up over a charging pad and automatically starts charging — without plugging in.

Not being an electrical engineer by training, I fumbled over what to call this thing – “wireless charging”? “touchless charging”? “plugless charging”? – finally settling on “thing with wireless piece” in my intro to this demo in which Geoff Ryder, Sustainability Principal at SAP, clarified what’s actually happening in conversation with Adam Langton, Energy Regulatory Analyst at the California Public Utilities Commission:

Despite my fumbling over what to call this (the manufacturer, Evatran, favors Plugless Power, and in the streets people know this as “inductive charging”), I could imagine how this could change the game entirely for the electric vehicle and more should these things become ubiquitous.

Not so with this decidedly curmudgeonly take from Paul Scott from Plug In America:

I think it’s kind of silly, to tell the truth. Not that it doesn’t have applications, but if they think people will like EVs more because you can drive over a spot in your driveway and charge, saving you the arduous task of having to (gasp!) plug in your car, then they don’t understand the nature of the American people I grew up with. Most of my friends are perfectly willing to spend the three seconds it takes to physically plug in the car.

The American people Paul would have grown up with, however, did not have to gas up their cars multiple times a day.  Without long-range EVs available to most of us, the typical EV driver currently needs to constantly worry about where to find the next charge.  This is hardly a “sexy luxury” – this is a true need of today’s consumer EVs.

If you can imagine a future in which inductive charging is not just in every parking space but actually embedded in our roads, then you can imagine how this changes the game not just for EVs but for vehicular transport in general.  According to the Rocky Mountain Institute:

Wireless charging is a big topic among car-share services because EV operators in a car-share often forget to plug in the car, leaving a drained battery for the next user. Embedding inductive charging within roads could actually supplement EV range and reduce range anxiety. For instance, the Nissan LEAF is rated at 73 miles on a charge. A trip from Los Angeles to Las Vegas can’t happen in a LEAF, but if inductive charging was available every 50 miles while you drive in a boost zone, today’s EVs could make the trip.

In this future, one way or another, you can make the trip and never have to get out to charge — or put fossil fuels into your car — ever again.

And in that future, if you don’t even have to connect to anything to charge, maybe the sky’s not even the limit.

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  • I disagree with Paul Scott… inconvenience is one of the detractors or barriers to adopting electric vehicles today, so eliminating those barriers becomes another reason eliminated from the list of “why not” an EV. 

    I think of all the times (like right now) I’m sitting at my desk with a perfectly good plug just an arms-length away, but yet my mobile phone is not plugged into it and re-charging, despite the fact that the phone has a notoriously bad battery life and needs constant re-charging… 

    If simply parking at work, at home, while shopping or dining, all automatically charge your vehicle, that’s a benefit.

    I think the “touchless automatic re-charging thingy*” is a breakthrough.

    * TART, trademark pending, which I would gladly give-up rights to for a Tesla Model S (in red please).

    • I’m mixed on the idea of “inconvenience” — on the one hand, we shouldn’t have to be electric (“TART” 🙂 ) engineers to drive electric cars and in the future they should just be called “cars,” without us having to worry what they’re charged with — and on the other, as long as the act of fueling and driving has global ramifications and emissions, driving our car is not a civil right, but a community privilege – and “convenience” should not come with the package. 

      Having said that, if we invest more in renewables and make the charging world a fossil-fuel-free place, we all tread more lightly.  All of us, Paul Scott included, should have an interest here.

  • As an owner of a Chevrolet Volt myself, I tend to agree with Paul’s opinion. It is much cheaper for companies (such as SAP) and individuals to install plugs into their garages than an inductive charging device. Not to mention that there is virtually no inconvenience from plugging in the car.

    The cost to make roads/highways inductive chargers, and the waste that that would create actually boggles the mind. You would need to have a 240V (or multiple) with at LEAST 12 amps of current running however long you want your section to be. Just from the inefficiencies of copper, you get over a 30% waste of electricity from its transport. Copper, by the way, isn’t cheap, but it is the cheapest way to transport electricity. Building these things with super conducting materials would make the cost astronomical.

    I don’t know how big the inefficiencies related to the inductive charging themselves are, but I assume that they are larger than having a direct line to the EV’s battery. After all, air probably doesn’t make for a good conductor!

    • Christian, great comment – perhaps you plug in just as often, but do you really experience the same kind of range anxiety when you’re driving a Volt? For the electricity waste with inductive charging, Geoff indicated it’s 90% efficient now – not perfect but not bad – and potentially gains are head.  As for the infrastructure cost itself, sure is mind-boggling.  However, infrastructure is crumbling all around us — we can seize an opportunity to be future-thinking as a matter of normal maintenance… Just some thoughts.

    • Inductive charging is indeed less efficient than simple plug charging.

      It works by generating a magnetic field through a coil. A symmetric coil in your car captures this magnetism which makes electrons flow through the cable of the coil – which is electricity.

      knowing that such coils are made up of quite a lot of copper wiring, can you imagine the amount of cables you would have to embed in the asphalt?

      The simplest solution today, is a hybrid car, which has a range of 50 miles electric and another 300 miles on gas. if you plug it in consistently, I’m pretty sure you can reduce your fuel consumption by 70% (or maybe even more). Especially for short commutes, or store visits.

      imagine that the hybrid also runs on biodiesel.

      oooohh, interesting. we could cut down our dependency on fossil fuel even further.

      But that’s theory, because we still have to exploit large mines to get the necessary minerals for batteries, magnets and wiring for the engines. We still deforest large parts to replace them with biodiesel farms. (unless we maybe use alges…)

      We seriously have to find a good solution and balance to come up with environmental-friendly transport, without damaging nature (too much) on the other end of the process.

      • Makes sense that inductive charging can’t match plug-in / touch charging in efficiency – but perhaps there are futuristic ways to work around that that I don’t pretend to understand.

        True this:

        > But that’s theory, because we still have to exploit large mines to get the necessary minerals for batteries, magnets and wiring for the engines. We still deforest large parts to replace them with biodiesel farms. (unless we maybe use alges…)

        It’s the whole supply chain we have to worry about.  And this is just me personally and no corporate endorsement, but I was impressed by Tesla’s recent announcement that they would blanket the US with superchargers — powered by solar energy.  Yet you’re right – in my understanding lithium is a critically endangered resource, and that’s not to mention the other car parts. 

        I also like the promise of biodiesel and algaes. Also: dirt-powered fuel cells, anyone?

        Thanks for the comment.

        – m “walking today”

        • Dirt powered fuel cells — Back to the future?

          A lot of progress is being made in the area of batteries, and replacement for silicium has been found as well (grafeen)

          So it is possible to be sustainable on both ends of the supply chain. There’s still a long way to go, but there is hope.

          The ideas that Tesla is promoting aren’t new and not even radical. The big difference is that Tesla is actually doing it, instead of just talking about it! I think they’re doing a great job at pioneering a sustainable future.

  • One of the uses would be city bus fleets.  You could put these at locations where the bus stops for awhile (train stations, transit hubs, where bus drivers take a break, etc. ) so maybe the bus would get a little bit of a charge in a couple places over a day, thus giving them more range. 

    Other fleets would have the same advantage.

    Personally I love the idea, but it does seem like a waste to loose that much energy. 

    There is a great unanswered question, can you charge your phone on it?

    • Ha – just set the phone on top of the Plugless thing?  I wonder also about radio interference – but then again, I already proved I wasn’t an electrical engineer.  In San Francisco, some people got hurt just today with the overhead lines used by electric buses – so it’s conceivable that in-road charging could also be safer in the long run.

    • The application of wireless charging of public transport buses is indeed the first start for wireless charging. Buses uses a lot of power and drive predictable rounds with fixed busstops for charging. In the Netherlands and Europe we already have wireless chargers that can charge up to 120 kW with an efficiency of 95%. This efficiency is equal to the best plug in fast charger available.

      The cars will come later as the price of the chargers go down from the 3000 USD to a plugin price.

      More info at or

      • Thanks for that pointer Peter — where are the wireless chargers mounted? Are they in-road at regular intervals or something? 

        The overhead wires for the electric buses in San Francisco seem so accident prone and are an eyesore as well as a danger — they must have been a lot of infrastructure to invest in as well.  But I don’t know if SF plans any wifi chargers for public transport — and this is a good reminder for me to go research that.  Thanks.

        • The wireless chargers ar implemented in italy (turin and genova) and the second generation in den bosch and will be implemented in utrecht ( the netherlands) and milton keynes (uk)

          All these are at the same cost level as regular diesel buses

    • Thanks for that tip Christian – so do you think we’ll start to see more of them? And do you charge multiple times a day with the Volt or will this plugless charging continue to seem like overkill?

      And, I’m glad the article acknowledges that “Plugless Level 2 Electric Vehicle Charging System” is a tongue-twister 🙂