When will electric vehicles provide grid storage? | RenewEconomy

When will electric vehicles provide grid storage?

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When and how will we be able to use EVs to store energy from our solar PV system and provide mobility and power our homes?

A co-located Electric Vehicle (EV) charging and solar generation facility at the CERES Environment Park in East Brunswick – an example project of the type that is a stepping-stone for EVs as grid storage (Source: CERES).
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Close your eyes and picture yourself in a sleek new electric car – powered by clean electricity, emitting no pollution, silent and cheap to run.  Parked in your garage, it stores energy from your solar PV system to provide mobility and power your home.

But is it going to happen?… And if so, how and when?

The vision of parked vehicles being used for grid storage has captivated people since EVs began (re)emerging as a viable transport option – wind and solar variability could be solved through intelligent application of an underutilized asset!  Now with solar uptake booming in the U.S. and over 180,000 plug-in vehicles on the roads providing 4 GWh of potential storage capacity, the time has surely arrived to pull the pieces together?

The good news is that the technology is here or not far away.  Advanced vehicle/grid control systems can protect the battery and manage energy flows in line with network needs.  Interoperability across the various technology interfaces is advancing through the evolution and application of recognised standards.  These developments will provide enhanced visibility and control for network and vehicle operators, allowing them to cooperate easily, conveniently and for shared benefits.

The story from here will reflect the realities of car use, the insights from Big Data, and the power of visual association.

Experience has shown that vehicle owners are largely, but not entirely, predictable – most use their car during the day and charge overnight. While charging tends to happen when it is cheapest, drivers manage charging in line with the primary use of the vehicle as transport.  For energy service providers this translates to uncertainty – not a great foundation for business success.  When viewed alongside the relatively small storage capacity of individual vehicles relative to stationary batteries, the focus for the foreseeable future will be on the alternative.

The areas of opportunity are instead those with more certain benefits that outweigh the cost and effort involved in setting up the vehicle-to-grid system.

An obvious example lay in use of the cars for emergency back-up power, when access to electricity may be life-saving.  Equipment available now allows EVs to be used as a direct power supply independent from a hardwired electricity network.  Use of the vehicles as storage within independently capable and controllable microgrids has been identified as a means of providing increasingly valuable system resilience.

For non-emergency applications, the pathway will be through evolution of existing grid-connected installations – analogous to that unfolding for microgrids above.  Electric vehicles often operate out of locations that also feature distributed energy resources, such as solar PV.   This coincidence is intended, as the visual association of the two technologies provides significant “brand value” while in the early-market adoption phase.

Through analysis of the energy and vehicle activity data at these locations, much can be discerned about the opportunity for surplus energy to be directed to the cars when parked.  Individualized system design and control strategies can then be developed so as to deliver more certain benefits for only incremental investment.  These projects will serve as a stepping stone for the mainstream, commoditized solutions of the future, where cheap, clean and locally-produced energy is used for transport or stored in vehicles for later re-use.

Bringing these individual, site-based solutions together in the wider network context will unfold as local electricity market regulation allows and incentivizes it.  Regional operators may manage a number of distributed energy resources from across their network collectively as Virtual Power PlantsProjects of this type are already underway, endorsing the view of the future utility customer as a ‘prosumer’.  Through this model, a car may provide grid support from various locations within a network as it relocates over the course of a day – a scenario that represents the ultimate realization of the vehicle-to-grid concept.

For individuals who want to get the ball rolling, the first step would be to compare a record of vehicle movements with the generation profile of your home solar system.  Understanding the overlap will highlight the potential to generate your own transport energy.  Managing your EV charging to consume surplus energy generation may provide a financial benefit that would offset the absence of a feed-in tariff.

In the near-term the cost and effort involved will likely appeal only to the minority for whom the sometimes intangible benefits really matter.  These ‘early-adopters’, who will be strongly motivated by the visual synergy of co-located vehicle charging and solar generation, are a feature of any new technology adoption.

As the pathway seems clear and the technology is here, the future is now.

A co-located Electric Vehicle (EV) charging and solar generation facility at the CERES Environment Park in East Brunswick – an example project of the type that is a stepping-stone for EVs as grid storage (Source: CERES).
A co-located Electric Vehicle (EV) charging and solar generation facility at the CERES Environment Park in East Brunswick – an example project of the type that is a stepping-stone for EVs as grid storage (Source: CERES).

Kristian Handberg is a Principal Consultant with Melbourne-based cleantech start-up Percepscion.  From 2010 to 2013 he designed and delivered the Victorian Electric Vehicle Trial.  This article is based upon a February 2014 White Paper from the same author titled “Electric Vehicles as Grid Support”.


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  1. coomadoug 7 years ago

    It doesn’t matter when or where the car connects to the grid. The travel plan is in the home, car and grid smarts. The car energy and economics is optimized.

  2. Bob_Wallace 7 years ago

    For a long time to come EVs will likely use the most expensive batteries available. Because the batteries that store the most energy per kilo will be the most expensive.

    Using up those batteries for grid storage probably will make no sense. Utilities and end-users will be able to purchase much cheaper storage. Not as ‘compact’/lightweight batteries.

    As for emergency backup, the Nissan Leaf is already set up to do that. Comes with a built in inverter.

    • RobS 7 years ago

      Lithium Ion batteries used in EVs currently cost around $300-400/KWh and have about 2,000-3,000 life cycles. This means the amortised cost of each Kwh of battery is 10-20cents. Which means that as long as the spread between purchase and sale price of any power stored by an owner in a V2G scenario is greater than 10-20 cents then using battery capacity for V2G services will make economic sense. In many areas with TOU metering 6-8c for off peak power and 25-30c+ for peak usage are quite commonly encountered numbers meaning without any further power price rises or battery price falls V2G is potentially economically justified right now.

      • Bob_Wallace 7 years ago

        10 to 20 cents may make sense for some customers in some markets.

        My point is, there is cheaper storage. We are at a point at which EV storage and bulk/utility storage are starting to bifurcate. Bulk storage does not need to be as compact/light weight as EV storage and will likely be cheaper.

        • RobS 7 years ago

          I agree industrial size storage and utility scale storage can use cheaper but bulkier storage like a liquid flow battery. However if residential storage coupled with distributed generation is going to take off then I think the storage modules will need to be the size of a small refrigerator in a non intimidating maintenance free format and that basically means lithium ion.

          • Bob_Wallace 7 years ago

            I just don’t think people are going off grid in great numbers due to the effort and cost of covering the “second, third, fourth, ….” cloudy days.
            I can see some people moving to “first day” storage, putting away enough of their own solar to carry them until the next day.

            People who do go off the grid are more likely to do so for attitudinal, not financial reasons. There will be a few (like me) who find it much cheaper to go off grid, but we’re likely no more than a small fraction of 1%.

          • Ronald Brakels 7 years ago

            Bob, people will only go off grid in towns and cities in Australia if we bolt the dog, or Alan key the hound, or whatever the American expression is and basically drive people off the grid with supply charges. In any sensible universe Australians in built up areas will stay on the grid and people would be charged for electricity in a way that did not give them an incentive to leave. However, I have to admit that at the moment we are clamping the chihuahua.

          • Bob_Wallace 7 years ago

            Gluing the setter?

          • Ronald Brakels 7 years ago

            I think that might be it. Richard Nixon glued the setter. Yes, that sounds right.

          • Bob_Wallace 7 years ago

            Nixon did have an Irish setter.

            He also had a poodle. No one has ever discussed what he may have done to Vicky the poodle in the privacy of the Oval Office….

          • RobS 7 years ago

            I am not talking about off grid systems requiring ~5 days of storage capacity, they only make sense where there are kilometres of power lines at a cost of ~$10,000 per kilometre required to connect a property to the grid or for the serious ideological off grinders. I am talking about grid interactive hybrid storage systems with ~1 days consumption worth of storage capacity or possibly even less allowing owners to store surplus daytime generation to use in the evening and night time. The grid would then remain as a backup during periods of low solar production however the storage would then still have a role allowing the grid to only supply those properties with power at non peak periods at far lower cost, a form of supply response. The alternative is to feed surplus power in to the grid and buy it back at retail costs later, this has been the norm for many years however with the strong push from utilities to slash feed in tariffs to reduce the value of surplus distributed generation the time when it is cheaper to store your power for self consumption than buy it at retail rates is fast approaching. There are very few even going partially off grid presently, however just like solar installations that many were convinced would remain a niche specialty product of the economically challenged and ideologically committed became a flood once the economic tipping point was reached a few years ago once that tipping point is passed for storage the same surge in interest will occur.

          • Bob_Wallace 7 years ago

            I wouldn’t calling the installation of a few hours of storage ‘going off the grid’. That term has always meant ‘no grid connection’.

            I do think grids will end up with two or three types of customers. Some will continue to use the grid as they have and pay the monthly bill. Some will install solar. Some will install solar and some storage. Then there will be a very small niche of truly off the grid people. Too small to be important.

            Utilities have a narrow window in which they can prevent having too many people install storage but to do so they will have to treat solar owners “nicely”. And that might mean losing some money on the power exchange for a while.

            Utilities are going to have to figure out how to be a lower cost ‘storage’ option than buying ones own storage system.

            Utilities are going to have to figure out how to get their surplus thermal plants off their books without cramming the cost down customers’ throats. That will drive people to install more solar, storage, or cut the wire.

            Utilities are going to have to hang on through some bad times while they rid themselves of legacy plants and build their business back up with EV charging.

            That utilities are not championing EVs makes no sense to me. There’s a brand new replacement market just waiting for them. They should be funding leasing programs and installing rapid charge stations.

          • RobS 7 years ago

            I wouldn’t call it off grid either, thats why I brought it up in direct response to your comments about ON grid storage of intermittent generation

    • Ronald Brakels 7 years ago

      $13 a kilowatt-hour is what electricity can cost during critical peaks here. That’s more than enough to pay for wear and tear and even the most expensive electric car battery. Of course, it won’t take a lot of storage to make those times when electricity is that expensive quite rare.

      • Warwick 7 years ago

        Hmmm, not likely. If homeowners were able to face wholesale market prices, they’d be lucky to get one or two half-hours of $13/kWh in a year(assuming the car was also at home). Taking the Nissan leaf as an example of a 3.3kW charger if it’s also able to discharge at the same rate, we’re talking $22 for each half-hour for a couple of half-hours a year, if the car is home during the day when the peaks usually occur.

        • RobS 7 years ago

          But you ignore the 5-10 half hour blocks at $12, 20-30 at $10, 30-50 at $8, 50-100 at $2-6. Add them all up and ou can potentially earn ~$700 a year simply for having your car plugged in.

          • Warwick 7 years ago

            I ignore these blocks you describe because they are simply not there. Taking NSW as an example…there have been zero occurrences of prices above $2/kWh this year and none at all for the whole of 2012. In 2013, the only prices above $2 were $7.70 and $2,45…giving your Nissan the earning potential of $16.40…nowhere near $700! It sounds like a good idea, like going off-grid but the economics are still a long way off.

          • Ronald Brakels 7 years ago

            Warwick, if it’s a simple matter of going online and typing in that you’ll sell electricity to the grid when it reaches X dollars a kilowatt-hour but alway leave Y amount of charge in the battery, then it’s not particularly complex and many people are likely to do it even if it doesn’t net them an impressive amount of money over the year. And as batteries decrease in cost then one can type in lower values of X and still come out ahead.

          • Warwick 7 years ago

            It’s not a simple matter, as you need to be a market participant and settle weekly with AEMO which requires prudential guarantees and registration hence is why there are retailers to do that. Retailers might be perceived as evil here on this forum but love them or loathe them they actually provide a credit function for small customers with the market. I suggest you look at the market prices for battery storage and then look at the arbitrage opportunities (i.e the $13,000/MWh) that are just so infrequent…it won’t stack up.

          • Ronald Brakels 7 years ago

            Warwick, the if makes the first sentence in my previous comment a conditional statement.

  3. Malcolm Scott 7 years ago

    I’m with you and trying to do the first step that you suggest, however….
    I moved into my 2 year old property in Dec 13 and requested a flexible tariff as I’m committed to consumption/price risk sharing and mitigation where it’s most appropriate.
    To my head banging surprise in this very young house in Victoria, it did not have a smart meter fitted. 3 months later United Energy installed the smart meter after I escalated. I still do not have access to the UE portal so I can retrospectively assess my net consumption profile. It is now almost two months without response to my email to UE requesting advice on load demand standards (if any given the standard is not final) that I might comply with for an EV charging station. The same email asked for procedures to integrate an in-home display using ZigBee standard with the smart meter so I can make real time decisions on when to consume my solar pv to charge the EV, rather than use the overnight renewable energy that I get from Momentum Energy.
    I would like to have a good relationship and a partnership with my energy company’s as they transition to new business models with value adding services, but hell they make it hard.
    My eyes don’t have to be closed to see a sophisticated sexy (I think, cause it’s red) pollution free car my garage. I also have a kit on the way for my EV to provide 2 kW emergency power capability or portable BBQ as I might want or need.
    Your message is real, now. No need to dream. United Energy, please work with me

    • Miles Harding 7 years ago

      Champion effort!
      What we all need, irrespective of our location in the country, are switched on suppliers that understand how to meet 21st century customers needs.

      Wouldn’t it be good to be able to access the meter’s instant data, but it may be a lot easier to bypass UE and install your own watt-hour instrument. There are some that may work decently, but my experience hasn’t been good with commercial products. The Watts clever isn’t. – it doesn’t measure power factor (current phase angle) which makes as good as useless in a house full of stuff with lousy PF.

  4. Gramus 6 years ago

    Transaction costs for all but large fleets will exceed the benefits from V2G.
    The operational constraints associated with EV use makes formal V2G a more marginal proposition than people think.

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