Six factors that make battery storage add up for households | RenewEconomy

Six factors that make battery storage add up for households

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New Queensland study based on a series of home battery storage trials gives some insight into what can make batteries interesting for households, what might motivate them, and how the network might use these assets into the future.

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Big family, big energy use, a big PV array, a big difference between the grid price and the feed-in tariff, and an ability to shift some appliances to the day-time: these are just some of the things that make battery storage an economically attractive proposition to households.

A study conducted by Queensland utility Energex, from a series of battery storage trials over the past year, gives some insight into what can make battery storage interesting for household, what might motivate them, and how the network might use these assets into the future.

The first thing to be noticed is that according to the small Energex survey, the environment does not figure high in the motivation of households to add battery storage to their solar arrays.

For them, it is all about reducing the size of their bill, even if – as we see below – it may not offer a quick pay-back right now. Making the most of their PV systems and saving the planet seems to be secondary considerations.

fig9 - BESS

As for making the economics of battery storage add up, it helps if there are many people in the household, if energy use is high, particularly after 6pm, if the difference between the grid price of imported energy and the tariff for exports is high, if there is a big PV array, and if there is an ability to shift consumption.

That pretty much makes sense, and the Energex trials suggested that the more solar that was self-consumed (i.e. stored in a box for use in the evening, rather than exported back to the grid), the better.

Its trials showed that all households reduced their bills, although the payback was still above 10 years, more than the guarantee period for the battery themselves.

This is likely to change as battery costs come down, by up to 75 per cent by 2030 as predicted by numerous studies, so that even by 2020 the payback period should be under 10 years.

fig10 BESS

The battery storage industry is still in its infancy in Australia, even though this is the country where the technology is expected to “grow up” first, simply as a result of the country’s ridiculously high grid prices, its excellent solar resource, and the world-leading penetration of rooftop solar.

According to the Energex numbers, battery storage installations are growing, but still only totalled 800 as at July, 2017 (see graph below).

fig3 - BESS

It is not entirely clear that Energex is actually aware of all the installations, given that there is no formal requirement to notify the network owner or the market operator – unlike solar PV systems which must be registered to claim a rebate.

And in Queensland, there is less incentive than elsewhere to install battery storage, given that nearly half of all solar households benefit from a  high and long-dated premium feed in tariff which gives no motivation at all to install batteries.

What does interest Energex is how the batteries can benefit the grid, and be exploited in a way that can provide “grid series”, reduce investment in new poles and wires.

Its conclusions were that they can be used to meet peak demand, but they need to be marshalled better. Left to their own devices, so to speak, batteries often used only 26-63 per cent of their useable capacity to support household loads during 4pm to 8pm.

It also noted that if all the batteries were charged in the morning – as most are now – then this does little to address “peak export”, or the so-called “duck curve”  where significant amounts of solar is exported to the grid at the same time.


fig16 BESS

This is an important point. Because if the amount of exports could be limited, it could mean that networks would feel comfortable in being able to double the amount of rooftop solar on the local grid.

Likewise, there is no point having batteries charged in late afternoon when the grid load is high. This will be a key issue when electric vehicles become more prominent.

The Energex trial concluded that by having these batteries interconnected, and by using demand response measures, than batteries do have inherent network benefits, in that they reduce peak demand and “peak export.”

The question for the network operator is how these benefits can be converted into a customer incentive and what minimum level of control do distributors (DNSPs) need to have over solar PV and/or battery storage, in order to enable the connection of higher levels of solar PV and BESS.

It suggests the question then becomes: Can batteries serve the interests of individual households as well as the broader network? Is it all for one, or one for all?

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  1. Craig Allen 3 years ago

    If a price signal were provided via a variable feed-in tarif then the grid operator would not need to have control of household battery systems.

    • Chris Drongers 3 years ago

      Pretty sure bet that already there are cabals of hooded utility acolytes trying to get comfortable with suited accountants and corporate strategists listening to the t-shirted and torn trousers ‘guys from the IT (and engineering) departments’ as the companies try to figure how to get the maximum value capture for themselves while leaving the absolute minimum to incentivise the householder to allow them access to the home battery. Unfortunately there is no evidence that Turnbull or his government would be on the side of the householder in this change.

      • Joe 3 years ago

        Chris your last sentence is spot on just look at the personal perspective of PM Turnbull who has home solar and battery but it was all his son’s idea….not Turnbul himself. The ‘Non’ Environment Minister, Joshie, has been quizzed about installing home solar all we got was…zero interest in the idea. These two tell us all we need to know about the thinking of The COALition..

  2. Joe 3 years ago

    Perhaps the motivation for people installing home solar and batteries is not as important as the fact that so many households are actually doing the business. Some 1.7 million Aussie rooftops have the solar and more are joining in all the time. This to me is the critical point to it all. I got started with home solar in 2008, when it was expensive compared to today, and it has always been about the environment for me. Sure the cost is a factor but I sleep better at night knowing I am pulling my weight in trying to keep planet Earth a sustainable place to live….there is no Planet B for us.

  3. MaxG 3 years ago

    “t also noted that if all the batteries were charged in the morning” … do I hear fear-mongering. It makes the most sense to charge the battery when the sun comes up — with solar PV, until it is full, and then export what is left.
    We had weeks of weather where the sun drops off around lunch time, sometimes producing less than what is being consumed.
    I cannot see how my stance could change, which is NO to an energy company tapping into my battery for their benefit.

  4. Ian 3 years ago

    Good news 44c/KWH tariffers: you can install more panels and batteries if these are connected to a separate and distinct system, check this out:

    Whatever you do , don’t try use other generators or batteries for your own consumption whilst generating electricity for the 44c/KWH tariff – unless these are connected to a different system.

    There we go again, vilifying Queensland’s pioneers of solar installation. The legacy installations represent less than 1/2 all household installations in Queensland and the attrition rate is quite high. The tariff was taken over by the Queensland government to honour its agreements made with people years ago and costs the network operators nothing.

    If you want these people to install batteries then you have to stop being so restrictive on the rules governing the tariffs. Fortunately the Queensland government has clarified these issues and the rules can be seen in the DEWS document. In fact, these legacy tariff households represent a very useful opportunity to kick-start the battery storage industry in a meaningful way.

    Many would be used to managing their demand to maximise their tariff earnings and would be shifting their electricity use to the night. Batteries on a separate connection would not change the quantity of electricity exported by these people but would allow them to reduce their peak evening usage and shift some of their discretionary loads back to the day time. The government’s liabilities for its previous agreements won’t go away but they can be used in an indirect way to help increase behind the meter storage from its current miserly 800.

  5. itdoesntaddup 3 years ago

    Because if the amount of exports could be limited, it could mean that
    networks would feel comfortable in being able to double the amount of
    rooftop solar on the local grid.

    So consumers get to pay for surplus capacity that’s not needed at midday. At least it’s logical when they are the cause of it. The issue is, is it cheaper to curtail, or to store?

  6. Jedi 3 years ago

    I don’t think I understand one of your points “and if there is an ability to shift consumption.” (which is reiterated in your diagram). Wouldn’t a battery be of more use if you _can’t_ shift consumption to during generating (daylight) hours or off-peak?

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