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If Tesla takes EV charging off-grid, we need to rethink energy

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A Tesla charging station. Source: Pixabay

Source: Pixabay

I have heard the casual refrain “electric vehicles will save the grid from the death spiral” too many times to count. The assumption is that people will charge their vehicles at home. That it would simply be too hard to supply the energy cheaply, in any other way, than via our century-old energy market.

Given Tesla is saying almost all of its charging stations will go off-grid, is it time to revisit this assumption? Absolutely.

I always enjoyed the phrase “to assume makes an ass of u and me”, a great way to remember the spelling, and so true as well.

The assumption that people will charge their vehicles at home with off-peak power is a cracker. Today, we don’t refuel our cars at home (or work), even though most people drive their cars to the same place everyday, park it for eight hours and then drive it home.

Charging your car at home not only requires a new pattern of consumer behaviour, it ignores the obvious opportunity – charging your car while it sits idle at work during the day, 5 days a week.

A 50km return trip to work will cost you about $1.50 in electricity. At that price, your company will probably pick up the tab, and it is certainly cheaper than the train ticket!

Need to shop on the way home? No problem. Looking at EV charging trends, many commercial shopping centres are realising the value of a free EV charge (in the hope of attracting visitors) is worth more than the cost of provision. Those same shopping centre’s are also putting MW’s of solar on the roof.

All of a sudden, instead of charging your EV at home, it looks like you will be returning home with more than 60kWh under the bonnet. 60kWh is enough to power a reasonably efficient home for six days. Still willing to bet people will charge their cars at home?

Set aside the practicalities of Tesla taking its charging stations off-grid for the moment (Musk is probably playing the crowd). There is a much easier off-grid play, once you join the dots.

What do you get when you join SolarCity with the world’s most recognised EV brand (Tesla), the world’s most recognised battery product (Tesla Powerwall) – and then throw some solar tiles in for fun? You get an irresistible combination of technologies which makes it oh so tempting to take the humble household off-the-grid.

A large solar system (5kW+), mid-size battery (13.5kWh for argument’s sake) and a car with 80kWh of storage is a compelling combination for a household energy solution.

The fixed solar and storage asset at home easily supplies your household power needs during a typical day. For six months of the year (summer, plus shoulder months), you probably have excess solar power during the day, perfect for topping up the car if it is parked at home.

For the other six months, your vehicle-to-home power supply kicks in, to get you through evening, morning and overnight peaks. You may have even charged your car (without needing the grid) at a Tesla charging station. If not, you charged for free at work, or the shops – talk about cheap off-peak power!

Apple didn’t create a smart phone by adapting a fixed line hand receiver – they re-invented the experience from scratch. It is time we did the same for energy.  

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  • ROSSC

    Mind blowing how quickly we are jumping.. And yet on my other webpage im viewing, there is Tony Abbott and the tin foil hat brigade telling us that coal is forever and renewables are a fad.

  • Chris Schneider

    Ok, You’re off your rocker! I have an electric car. (a Model S) There is ZERO chance even if it was between work and home I would be stopping there and waiting 30 minutes for a 50% charge. As I see it, one of the benefits of Electric cars is I DON’T need a fuel station and spend time where I’m not going. Add to that the limitation of 400kWh per car per year free (I’m excluded from that) and I will take my power from Home or work, thank you very much.

    The big shift here and the story is the admissions that using our existing Power networks and the required paper work is simply too hard and adds too much to the complexity of the project (and cost). It seems easier to just erect a Solar shelter for the cars and use it to charge Batteries which are used to charge the cars. It also means that it can be done a LOT faster as there is no real limit to the power supply. The system might still be connected to the grid though for regulating the battery charge or for outputting additional power.

    It would be great if the power grid worked in with the renewable energy market but it seems they are going to cut off their nose to spite their face! Reality is a Grid connected Tesla Supercharge station (with Batteries) could do a lot to help with power fluctuations in the grid and a whole raft of other issues but it seems the old guard just won’t listen.

    • deanstennett

      Chris
      You are spot on….and here is the solution you described working in real life on a private industrial estate since late 2016.
      https://www.linkedin.com/feed/update/urn:li:activity:6249648066169839617
      Picture shows an i8 on rapid charge.
      Current configuration offers rapid / fast charge 50kW & 22kW for all EV models.
      Station also offer grid support via bio-directional battery energy storage i.e. offers grid balancing demand response capability, is also connected to renewable energy generation source (in this case small PV canopy, can be other or scaled) and is physically deployable / re-deployable in hours / days (subject to consents). Now looking to “scale up” capacity and deployment and would welcome enquiries to [email protected]

    • Ian

      Horses for courses, Chris. No probes with the charge all day at work under a solar shelter -perfect, why not indeed. 5 kw array for 8hrs should give you 30KWH of charge – plenty for the commute, the house at night and the commute back to work the next day. The 400KWH a year freebie recharge should fill in the gaps when your solar arrays are affected by cloud and rain.

      This idea of going solar for all your energy needs and still being able to live the suburban life, has a lot of appeal. Sure beats living in a high rise estate, near a high speed train dashing to the factory, in a shoulder to shoulder carriage with countless other workers.

    • Tosh Szatow

      Do you ever drive to work? Or the shops? Or have other regular destinations? Do you charge your car anywhere but home?

      • Chris Schneider

        Given I said I charge at home and work the last question is extremely strange. I charge everywhere it doesn’t inconvenience me. Some times I’m in town so I find a carpark with a destination charger. I haven’t got a shop around me that has a charger so don’t do that. On long trip I use superchargers but have complained to Tesla about their locations it really isn’t the way of the future unless the cars are Autonomous then who cares.

        • Tosh Szatow

          Apologies I missed the charge at work bit. Seems your car would be a good candidate for supplying energy to your home overnight?

          • Chris Schneider

            It would be a perfect setup! in fact it would be great at work too! removing all need for battery storage during the day at the office and all need for it at home outside the hours between when my GF gets home and I do. I don’t know why this isn’t already something Tesla have supplied to their customer. I think we would all take advantage

          • Tosh Szatow

            Ok cool, I probably misinterpreted your initial response to the article. Happy electric travels

    • Richard

      Elon said the supercharging stations would be off grid. That is a very clear statement.
      And it will send shudders through the energy markets

      • Chris Schneider

        why? because an industry that didn’t exist will not join the grid? it’s quite irrelevant to them. it would be better for tesla if they were connected though

        • Richard

          Why! Because if you can take a car recharging station off grid then you can take just about anything off grid. And I think Tesla would know a little more about what is good for them than you, no disrespect.

  • Michael Dufty

    Charging at home is one of the big benefits of owning an electric car for me. Seems an entirely reasonable assumption that most will be charged at home. I also fail to see the attraction of using a vehicle battery to power the house, since I probably want that charge to power the vehicle the next day before the solar power is there to recharge it.

    • Chris Schneider

      if it does it will be all done automatically. it qill underatand your commute and know how much energy can be extracted from the battery. it would be great for me. the office solar would power my house at night

    • Tosh Szatow

      We are all different Michael but I wouldn’t let your personal preferences limit your view on how this market may develop. There are still plenty of people struggling to give up their landline phone

      • MaxG

        Tell me all about it… I am building a house with lots of smarts… no light switches — can you imagine the debates I had around this one.
        Yet in my world, an ambient light sensor knows what is happening outside, while room sensors know what they end up getting and the light is augmented by LED lighting at the right level… motion and presence detected…

      • Michael Dufty

        As an EV owner I think I have a useful perspective though. I expect charging away from home may become more common when EV ownership gets to 50% plus, but it is very dominant at the moment. That said, I don’t drive my car to work, and I do actually charge my ebike battery at work to allow a smaller battery
        .

        • Mike Dill

          My work has a charger that I can use during the day. No reason not to charge there. (I do not work at home.)

  • MaxG

    There is a difference between ‘what could be’ and ‘what is’.
    Of course it depends on where you live and work, what infrastructure is there, etc. But, if the car is driven to work (and usually peak hour in the morning for most) than its battery needs to be somewhat full to make the round-trip; coming back after dark, means there is no sun to charge from, and no battery big enough to charge the car.

    What I see is that the car needs to be charged during the day, but where?
    I reckon the self-driving car would be the solution; as it drives itself to a charging stations, be it in some car park at the city fringe, or actually driving home to get charged — for those who drive less than ~50km.
    After than the cost for tires, the rest remains the same.

    Even if I am dreaming… this problem of where to reasonably charge your EV without burdening someone else is quite a tough problems — I have not been able to solve (for myself) yet.

    • Ian

      Buggered if I will let my model S roam around the city on its own scrounging for electricity, mate. You’ve got to look at the design specs. Supercharger power transfer 120KW, battery pack 90 KWH, consumption about 200WH/km. And then look at the average commute -40km/day in Australia, what’s your nightly energy consumption? 10 to 15KWH maybe. The energy habit is far less than the battery pack size, and the supercharger far quicker than the average person’s patience threshold. According to the specs, the recharge time for the day’s transport and home needs is probably less time than it takes to walk into the servo, grab a coffee , take a pee and look at the mags!

      • Richard

        Yes, the best way for many people to go off grid will be to buy an electric car which can supply power to your home. Combine that with home batteries and solar roof and a smart system that keeps you out of trouble and adapts to individual circumstances then bobs your uncle, bye bye grid.
        Tesla has been all over this for ages.
        The down side is that the grid will collapse in a lot of places.
        Either requiring lots of generators or a government owned and maintained grid requiring increased taxes to pay for.

    • Tosh Szatow

      EVs are coming out with 400-500km+ range. I don’t think the round trip will be a problem for most people

      • MaxG

        Yes, I guess, it really depends on what the round trip is… when I lived in suburbia it was 15 km in and 15 out of the CBD; come back Friday charge all weekend an you’re good to go.
        Now I live in the sticks: 100 km to and a 100m from the CBD, this looks different.
        I am not saying there won’t be a solution; I strongly believe there will be… just can’t see it yet 🙂

        • Tosh Szatow

          fair enough Max, though even at that range, you are coming home with 3+ days of electricity in your car, assuming it starts at full charge. The majority of trips in cars are under 20km or thereabouts, and certainly the majority of commutes are less than 25km. So thinking about the mass market, that is a lot of storage to just drive around with, going underutilised (if you dont draw down car batteries at home)

  • john

    As soon as i get the Model 3 it will be charged at home during the day or from batteries at night this is perhaps not doable for everyone who is solar challenged.
    In the small roof area in a unit then perhaps those handy near by outlets also solar powered will be able to charge the vehicle for a cost perhaps.

    • solarguy

      “Charging EV from batteries at night” Hope you have a lot of spare battery capacity.

  • Brunel

    Has Elon not heard of transmission lines?

    Build gigantic solar power stations in sunny areas and then have a UHVDC transmission line to transmit that cheap solar power to the snowy areas and the supercharging stations in snowy areas will be solar powered.

    • Tosh Szatow

      perhaps he has, and considers using them, and the distribution lines, expensive?

      • Brunel

        That would be contradicting a statement made by Elon or SolarCity recently saying that the electricity grid should continue to exist and not be superseded by rooftop solar and Powerwalls. ie, houses should not go off-grid at this point.

        • Tosh Szatow

          Perhaps they were being “strategic” when issuing this statement? Do you have a link?

          • Brunel

            “The future for utilities is actually not a bad future; it’s pretty good,” says Elon Musk, the tech entrepreneur. “As we transition to electric transport, we’re going to see a significant increase in the demand for electricity.”

            https://www.greentechmedia.com/articles/read/elon-musk-tells-utilities-hes-not-really-a-fan-of-disruption

          • Tosh Szatow

            Looks like he is having a bet each way 🙂

          • Brunel

            I concluded a while ago that Elon is dishonest. Look at his battery swapping demonstration.

            Saying that it is faster than putting petrol in the tank and how the
            demo involves “the fastest petrol pump in the state”!

            I thought the battery stopping is done by robots but Mr Brjon Nyland went to the only battery swapping station and said humans swap the battery by hand and you have to make an appointment to swap it!

          • Marley

            You took the word of Bjorn Nyland? Good for you fella.

          • Brunel

            As opposed to the word of Elon.

            So one does not need an appointment to get the battery swapped?

          • Marley

            Elon puts his money where his mouth is, Bjorn Nyland puts his mouth where the money is.

  • Ian

    Can’t afford a tesla but am thinking of a battery pack from a crashed Nissan to charge at tesla’ssupercharger station and taking the electricity back home for those long cloudy days.

    • Tosh Szatow

      Spot on Ian. Given Tesla now own all major pieces of the household energy puzzle, they will be able to solve technology integration issues far more efficiently than others

  • Chris Baker

    Tosh I think it is a mistake to compare an electric car to a petrol car to understand what your refueling habits might be. Comparing it to a mobile phone will give a better idea of how your charging might work in practise. Who charges their phone anywhere but home or work? For me its so rare that I would ever consider charging it anywhere else. It does happen when I’m travelling and only then would I go to the trouble of looking to charge it from a public charging station.
    I think you’ll find that a phone is a better analogue for an electric car. Our habits with present day fossil cars are a very poor indicator of electric car charging behaviour.

    • Tosh Szatow

      Hi Chris, I don’t think how we use phones or a fossil fuel car is a good comparison to how we may use EV’s. We have an opportunity to rethink energy and create new solutions unencumbered by history. I strongly believe Tesla will be taking homes off grid

      • Charles

        The “off grid” thought is overhyped. We will still need the grid for the small fraction of “extreme” weather conditions where solar and batteries won’t work. My PV system generates about 10 kWh on an average June day and about 50 kWh on an average summer day. My batteries array would either be massively undersized or massively oversized to deal with this. Solar+a single 14kWh battery will cover 95% of load for most homes, but you need several batteries to cover that extra 5%. It’s cheaper to stay on the grid.

        • Mike Dill

          I agree with the 95% but getting a generator set for the remaining 5% is very close or lower that my grid connection. I am not there yet, but the numbers seem to show it getting closer to parity as the utilities keep jacking up the connection costs.

          • Tosh Szatow

            agree Mike, those connection charges will only go higher as grid utilisation rates drop

          • Charles

            You can’t sell your excess solar with a diesel generator.

          • Mike Dill

            Electricity from a small FF generator is way more expensive than what I get off my panels, and selling it it stupid. What I was saying is that IF i disconnect, I will need some backup for the other 5% of the time. A FF generator can fill that gap, but it is expensive ($0.50/kWh or more) on a small scale.

          • Charles

            So you would size your solar/battery system for your typical summer generation then? Which means over winter, that’s a lot of diesel at 0.50c/kWh.

          • Mike Dill

            I expect to size for my PV array for normal winter months, assuming that there are days when the sun does not shine and I need a backup. ‘Extra’ summer electricity can run my pool pump longer and dump into my NG water tank. Worst case, I leave my lights on all night or do something else to ‘dump’ the excess production in the summer.

            Extra PV is cheaper than generator power. What would you suggest doing with the extra power?

          • Charles

            “What would you suggest doing with the extra power?”

            Well, that’s why I’ve been recommending staying grid connected. If you are anything like me, enough solar to get through winter will mean you will be generating 5x the amount your house needs in summer. With that much excess, even the lowest feed-in tariff is going to make you more than your connection fees.

        • Tosh Szatow

          I am suggesting the 80kWh battery in your car would be the back up. Starting with a full charge, you could do a 300km round trip and still come home with 20kWh+ without charging during the day.

  • Richard

    Yes, the best way for many people to go off grid will be to buy an electric
    car which can supply power to your home. Combine that with home
    batteries and solar roof and a smart system that keeps you out of
    trouble and adapts to individual circumstances, then bobs your uncle, bye
    bye grid.
    Tesla has been all over this for ages.
    The down side is, the grid will collapse in a lot of places.
    Either requiring lots of generators or a government owned and maintained grid requiring increased taxes to pay for.