How far away is grid parity for residential battery storage?

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It is now generally recognised that rooftop solar has reached “socket parity” – meaning it is comparable or cheaper than grid prices – in many countries over the last few years. The big question for consumers and utilities is when will socket parity arrive for solar and battery storage?

Some suggest it is years away. Others, such as UBS and the Rocky Mountain Institute, say it could arrive in Australia and the US within four to six years. It may come even earlier.

The graph below comes from Germany Trade and Invest and outlines the metric that will govern the arrival of grid parity for battery storage. Electricity prices are rising, solar PV prices are falling, which means that if battery storage can fall to around €0.20 per kilowatt hour, then parity will be achieved.

Australian research house Morgans, in an assessment of Brisbane-based battery storage developer Redflow, suggests that its zinc-bromine flow battery may already be commercially economic in Germany, which leads the world in terms of household adoption and government support for renewables.

battery parity

Morgans notes that in Germany, the cost of household grid power is around €0.30 per kw hour ($A0.42/kWh) and the government is now subsidising residential energy storage systems that are connected to solar systems.

“Given Germany’s substantial adoption of solar PV their costs for solar power range from €0.10- €0.15 per kw hour (half the grid price) so when energy storage costs reach €0.15 -€0.20 this will mean renewable energy costs will be at parity with grid prices,” Morgans says.

The German government is currently subsidising up to €3,000 for energy storage systems. Morgans says that the €0.15 – €0.20 per kw hour range (discussed above in figure 5) for energy storage costs, combined with the German government’s €3,000 subsidy for energy storage systems means the RFX ZBM will be competitive if they can triple the cycle life.

“In our view this should be achievable,” it says.




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  • juxx0r

    This is the numbers i get using landed, tax paid Balqon ES30 prices scaled where necessary:

    • Motorshack

      I see on your bottom line that LCOE and system size are inversely related, and this does not surprise me. I only use a couple of kWhs per day, and a couple of months ago I priced out a system of suitable size to see what it would cost and how long it would take to pay back.

      The cost was only a couple of thousand dollars, but power from the grid here is only $0.17(US), so the payback was something in the range of fifteen or twenty years, even if I paid cash and avoided all interest costs.

      I also did not try to cut costs to too aggressively, because it seemed like a false economy, and, in particular, I need a clean sine wave for my computer, as well as at least 800 to 1,000 watts to run a microwave twenty or thirty minutes a day. So, no cheapo inverters need apply.

      In addition, the power grid here is already fairly low-carbon because of a big nuke, a fair amount of hydro, and very little coal.

      So, unless I thought the grid were going to fail altogether, on a long-term basis, I really do not have any great reason to leave it. Neither the costs nor the environmental considerations are at all compelling.

      Of course, at Australian prices it would be a different game altogether, and I would be all over it.

      • juxx0r

        There’s no escalation of electricity prices in that either, if you put it in, then we’re almost at a tipping point. For me, i might just do it anyway.

        My cost of power is $0.27 /kWh plus daily connection fee of $0.50. Unfortunately according to the table i use too little power.

        • Motorshack

          Yikes, $0.50 a day for the connection fee!

          My basic cost, exclusive of heating and cooling (which I account for separately, since they could be done other ways) is only $0.35 a day, and even if I add in the heating and cooling the total bill averages less than a dollar a day on an annual basis.

          So, your connection fee alone would add more than 50% to my power bill, even in the most favorable case. In the worst case it amounts to a hike of over 140%.

          I would be off the grid in days, just on general principles.

          Frankly, I can’t believe the abuse you folks take from your power companies. Around here it would likely be pitchforks and torches as far as the eye can see.

          The official state motto is Live Free Or Die, but the unofficial (and much more realistic) one is Live Cheap Or Die, and they really mean it. Biggest tightwads in the country, by far. Famous for it, too.

          • juxx0r

            We have to pay the Australia tax for everything too.

            Recently i sourced a widget in Europe for $171, all good, where do i sign up? They redirect me to their Australian agent and i’m suddenly paying $358 for the same thing. So i pay more than the item is worth just to obtain it when airfreight would have been $35.

            So we take abuse because unless we source things ourselves we’re paying twice as much and even when you do source something yourself you can still get rogered.

  • Math Geurts

    Read: “Grid Parity of PV-Installations: A Full Comparison Considering All Taxes and Levies on the Power Consumption of Private Households in Germany”