Enphase's Energy System Hits Australia: Tesla Rival For Home Electricity Storage

Over in South Australia, the power networks are working with Enphase Energy to trial another new distributed energy storage system. Compared to Tesla's Powerwall (and some other existing battery storage), the system promises to be more flexible and has a smart management system -- but at what cost?

The stand out difference is that the Enphase system has opted for a much smaller capacity battery - just 1.2 kWh (vs 7 kWh for the Powerwall). That sounds too small to be much use, but the Enphase batteries can be ganged up together to work as a larger battery.

This actually has an advantage over the Powerwall, where adding in an extra battery is a significant investment that is hard to adjust to a home's individual power draw. Instead of being able to up the capacity bit by bit, you need to add an entire 7 kWh module.

The downside to the modular system is that it will likely always be more expensive to buy 5 or 6 batteries vs 1, to get the same capacity. This could be offset by lower install costs, as each unit is smaller and lighter and can be put into place by one person. It also allows homes to easily upgrade their storage capacity down the track.

Right now Enphase estimates that the system could cost $1150 per kWh, but that does not include installation and is only for volume partners. In comparison, the Powerwall costs around $600 per kWh - based on a $3000 US purchase price, and current exchange rates.

The $1150 per kWh figure is problematic, as (depending where you live) power costs around $0.25 a kWh (though whether this will increase or decrease in the future is hard to know). Assuming a free charging source (solar) and no install costs, it would take almost 13 year of operation just to give the same cost per kWh as buying the power from a utility.

Enphase suggest that two battery cycles are a day is possible, which essentially reaches the break even point in half the time - but how well that works in the real world remains to be seen. Factoring in all the costs and efficiency losses then the system is unlikely to pay for itself in 20 years, yet alone it's 10 year rated battery life.

Of course battery storage technology is about more than just the pure financials for an end customer, so we will be very interested to see the results of the tests. One application could be the power utilities offering the units at a subsided cost, as it could lessen their own operating costs by helping to handle peak loads.

What Enphase is doing is not exactly ground breaking - existing lead acid systems have a similar modular setup. But by combining Lithium Iron Phosphate batteries and some smart tech, Enphase could have a solid system that makes upgrades 'plug and play'.

Enphase also promises a 96% round trip efficiency, compared to the Powerwall's 92%. While the overall system efficiency, as well as battery capacity degradation is just as important, extra efficiency savings can help offset a higher cost.

Of course the true cost and subsequent savings won't be known until there is an actual installed price for the system. We did some preliminary calculations for Powerwall, and pending an exact sale price here in Australia, the numbers don't yet stack up for it either - at least from a purely financial perspective.

The Enphase system also has the Envoy S Wi-Fi connected smart power management system, which will let users monitor and control their power use from an app for best efficiency.

Just like other storage systems, the key points are better load management, especially with solar, as well as offsetting power bills with cheaper stored energy.

South Australia in particular has a lot of solar (25% of homes), but most of that electricity is generated outside of the peak draw time. The result is that the power stations can be throttled back during the day as solar takes over, but it needs to running full bore for the evening surge in power use.

With battery storage, some of that solar power can be saved and used to handle part of the evening peak. This puts less load on the power stations and electricity delivery infrastructure.

Right now the electrical distribution system has to be powerful and robust to ensure it can handle the peak load every day. With a distributed battery system, the peak load can be covered, meaning the power system only needs to cover the average load.

Helping start the shift to distributed energy storage systems is the Powerwall, which will be first available here in Australia.


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    After reading the article I'm going to pre-order one of these. Sure I'm not going to save lots of cash but that's often the case for the early adopter in most technologies. I would like to see this technology succeed, I'm excited by it's geeky potential and over the long term it's not expensive. I'm sure I claw back 90% of the investment. Perhaps if I wait a year it will be more affordable but the quicker we all adopt this technology and the quicker we can move Beyond Zero Emissions the better.

    Sorry at more than double the kWh price of Tesla's powerwall they can forget it. How typical of Australia to offer a sky high price to something that's supposed to help us with sky high electricity bills.

      To be fair, the Powerwall has not released a price yet in Australia and neither setup actually has a fully installed cost.

      Nor do we know yet how these batteries will be most offered exactly.

      But considering Tesla and the Gigafactory churning out batteries, I imagine they will be hard to beat!

    I'm pretty sure I've read somewhere that Super Capacitors are making a comeback. Rapid advancements are being made to produce Graphene in mass scale for cheap. Soon chemical batteries will be old technology.

    The EU invested a billion euros to Graphene research along with large contributions from Korea and Singapore.

    Sometime last year they figured out how to print Graphene patterns onto substrate using lithographic methods (light).

    Graphene Super Capacitors will produce higher energy density, higher output current, faster recharge time, safety and reliability compared to chemical batteries. These will actually make cordless robots possible!

    How soon may be the only question. I believe the Apple Car is targeting the Graphene era, at least in terms of the power source.

    Last edited 07/10/15 12:53 pm

      Sounds good, my only concern is:
      Is any progress being made on economic graphene-production methods?

        I think the first to find it will be the last to speak at this stage. But who knows it may be impossible.

        Last edited 07/10/15 7:51 pm

    Power might be $0.25/kWh now but wait until the mongrels start using those smart meters to screw us over during peak periods where they start charging double or triple the rate. Home storage will suddenly become a whole lot more attractive.

      Admit it, you pulled that 'double and triple' figure out of your arse.

        With cheaper solar and things like battery storage as alternatives, I think power prices will actually go down over time to remain competitive.

          yeah you will be paying 1c per kilowatt hour and $1000 for network fees

            There are conflicting mechanisms.
            1: Lower prices: Improving tech.
            2: Higher prices: Material shortages.
            3: Higher Prices: Richer societies demand greater safety and over-design.
            4: Lower Prices: More demand because richer societies expect more comfort.
            5: Lower Prices: More competition.
            6: Higher prices: Attempts to mitigate global warming.

            I don't know the future, but I don't see anything that could cause a rapid factor of two change in price, because the system adapts. Heck, even viable fusion would take decades to have an impact!

          Hey Lindsay
          Are you sure that $3000 for the Tesla is correct?
          I've seen different

            The price is from Tesla - but keep in mind that is US dollars, and the actual price here is not known yet.


            What pricing have you seen?

              I stand corrected! - I had a $7000 number in my head for the Tesla

        Of course I did but it was intended to foster discussion and debate. I never suggested they were based on any sort of fact but you can't deny that the only reason power companies want smart meters is so they can vary the rate depending on time of day which of course means paying more at the very time you want to put dinner on the table.

    Interesting article. I'm looking at solar and a battery system for my home. The thing is in South Australia we pay 32c/kwh minimum. When you factor in South Australia's higher price a battery system makes a lot of sense. The higher price for power in the state is probably the reason why the state has been targeted by battery companies.

    Wouldn't it be better to offer this as a lease program? Sign up for a program where every other year you have the batteries replaced with better technology as it comes online.

    I am a Metro Solar customer and received a quote for 2 Batteries installed $4000 last night, was a bit pricey for mine. But this is all they had available to sell to me (2 batteries) as this is was a pre sale offer. Maybe better priced as you add more batteries???

    Does anyone know if these battery systems can be added to existing offgrid arrays?, I operate a 15kw Saltwater battery offgrid system that meets our requirements for upto 3 days without having to use generator, I can add more storage if required using same batteries installed but I am curious about whether other manufacturers battery storage system can be added?...does anyone know?

    I think a lot of people have been waiting for this to be launched. It's never a good idea for there to be a monopoly on goods in the market, especially when such goods should be as cheap and easily available as possible to people to make the biggest impact. The competition from the new brand should definitely improve the cost and accessibility for Australians now!

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