Combining home solar, batteries and EVs will be better deal than solar alone by 2024 | RenewEconomy

Combining home solar, batteries and EVs will be better deal than solar alone by 2024

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IEEFA report finds with “modest” suite of EV incentives, payback for rooftop PV, a home battery and electric vehicle falls to just five years today, and zero by 2030.

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A new report from the Institute for Energy Economics and Financial Analysis has found that by as early as 2024, it will be cheaper Australian households to invest in solar, storage and an electric vehicle in combination, than in a solar system alone.

The report, “Steering by the Southern Sun”, investigates the apparently enormous potential for Australia to capitalise on its exceptional solar resource and rooftop PV uptake to drive what has been slow growth in electric vehicles.

It notes that while millions of Australian households have invested in some 10GW of rooftop solar, and tens of thousands are starting to take up battery storage, the shift to EVs in Australia has lagged well behind other parts of the world.

This is a great shame for Australia’s progress on emissions reduction targets, of course, but according to the IEEFA team behind the report, published on Thursday, it is a massive missed opportunity to capitalise of the “synergistic nature” of these emerging low-carbon technologies.

Or, as the other half of the report’s title puts it, Australians “are missing a trick” on electric vehicles fuelled by cheap, self-generated solar power.

Factoring in decreases in battery prices and various state government incentives for home storage, IEEFA estimates the payback period for solar plus battery plus electric vehicle, today, at 8.6 years, down to 4.1 years in 2025, and under 2 years in 2030. And that’s without EV incentives.

With a “modest” suite of EV incentives, which the report notes are being used with great success in various countries, but particularly in Norway, the payback for solar+battery+EV falls to just five years today, and then zero by 2030.

This would be achieved, IEEFA says, simply through the savings generated by on-site power generation and from avoiding the cost of buying and fuelling a conventional car. But of course the rate of saving would depend on the availability of policy incentives.

The kind of incentives modelled in IEEFA’s “accelerated” EV scenario include tax exemptions from GST (10%), import tariffs (5%) and motor vehicle tax, which in NSW amounts to $A236 a year; provision of capital grants towards EV purchase; and other “softer” incentives, such as free public parking.

“Applying these combined incentives, the payback period on solar plus battery plus EV falls dramatically,” the report says, to the point that “by 2024, it is cheaper for a household to invest in solar, storage and an EV in combination, than in a solar system alone.”

As for the solar and battery systems used in the modelling, IEEFA ran figures on two different sizes of each: rooftop PV at 4kW and 8kW and; home battery storage at 8kWh and 14kWh. You can see how these combinations varied in figure 5, below.

“Australia is leading the world in rooftop solar market share, and people are looking around for the next carbon-free innovation,” said one of the report’s author, IEEFA analyst Gerard Wynn.

“The beauty of electric vehicles is they can be charged by a household’s rooftop solar plus battery, with savings generated by on-site power generation and from avoiding the cost of constantly fuelling a conventional car.

“When the government introduces the right mix of incentives, people in Australia will benefit from cheap, solar-powered charging for their vehicles sooner,” says Wynn.

“Electric vehicles are cleaner, quieter, and less carbon-emitting than conventional cars,” he added.

“With rooftop solar being installed at faster rates per capita than anywhere in the world, Australia has a big opportunity to jump on the bandwagon and reduce everyday bills for Australians even further, while kicking climate goals.”

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  1. Ren Stimpy 8 months ago

    EVs are an absolute thrill to drive and by far much cheaper to run than a petrol car. It’s only a matter time until the shit-torque and fuel-costly ICE’s are relegated to the minor leagues!

  2. Peter Farley 8 months ago

    If you skip the home battery and use V2G the payback is probably no more than 5 years today even if you occasionally have to buy power at a fast charger, not only is fuel and maintenance lower but depreciation seems to be as well

    • PLDD 8 months ago

      I thought it odd they didn’t seem to consider the V2G or H opportunity. Taking out a $10 to $15k home battery makes the payback a lot better.

      Do you think they knew it was possible..?

      • trackdaze 8 months ago

        With V2G or H it certainly makes a smaller cheaper home battery more viable.

        Thats If you size the battery for the typical day rather than to cover all bases. Just use the vehicle as a cover for the occasional high home usage day then I imagine a home might be ok with a 5kwhr battery where as a standalone would be 10kwhr

        • PLDD 8 months ago

          I would have thought a vehicle battery would cover the majority of homes usage as the PV electricity reduces which is were the bulk of the benefits of the business case lie. Most EV’s are at least 40KWh which dwarfs most home batteries.

          If anything the business case for the limited contribution of the home battery gets more tricky. It’s competing against off peak grid supply that covers any shortages – this could be midday charging of EV’s at work or in car parks.

          I almost feel the home battery is an interim technology that will be squeezed out by PV/EV and grid RE and VPP capabilities. The trick for the home owner is working out if it’s a slow transition or rapid.

      • Andy Saunders 8 months ago

        For many households it won’t be possible. If the family is a somewhat coventional one, the EV might be used to commute to daytime work, and not be available to soak up the excess daytime solar.

  3. Jon 8 months ago

    With a 2.5 person (2 adults & a toddler), single car (which is an EV) 10kW Solar (5kW export limit) and no battery our most recent power bill was $37 & at a guess 3/4 of an 8kg bottle of gas for the 3 months
    Did over 7,000km, never charged away from home.
    At rough numbers we manage charge about 85% straight from solar, we set a timer and charge the other 15% after the evening peak at 1.5kW draw, we buy 100% green power to make sure this is emissions offset. It’d be great to 100% straight from the sun but the practicality is that we both work (me 5 days, partner 3 days) and we have active lives, it’s a car, it’s mainly not at home during the day.

    We’re in the process of installing a 10 !kW (8.4kW usable) battery, not to save money but to reduce our draw on the grid during the evening peak.

    If you have the opportunity to go EV and solar, I highly recommend it.

  4. Phil NSW 8 months ago

    Is it worthwhile considering the reason why Australia has the highest per capita uptake of rooftop solar. I am not sure if business as usual federal politics can be consider good policy but I am sure it is the reason the “per capita folk” have adopted solar. Australians en-masse took up the solar technology to avoid the bill shock created by government’s lack of renewable electricity policy. I am sick of hearing Angus Taylor spruiking how good Australia is in this area when it was his inaction that created the situation.
    His in action is the reason Australia is not taking up EV’s though. Lack of infrastructure, deliberate mis-information from government and no incentives. The fossil fuel lobby does not want BEV’s as it will destroy their monopoly more quickly. As this article shows it also will change the economics of electricity delivery with the battery storage capacity of the BEV’s being quite significant compared to house batteries.
    The tide is turning but will it be too late to safe the planet?

  5. MrMauricio 8 months ago

    Australia-land of the endless handbrake

  6. Alex Simmons 8 months ago

    Those payback periods for current battery solutions are a complete fantasy. And domestic batteries increase emissions, primarily due to round trip efficiency losses.

    • solarguy 8 months ago

      “Increases emissions due to round trip efficiency losses” from zero emission generation source, who do you think your kidding!

  7. Andy Saunders 8 months ago

    They may be called the Institute for Energy Economics and Financial Analysis, but part of their analysis seems off.

    There’s no way that the payback period of an investment can fall to zero as they suggest – unless there is no investment. I don’t see how that’s possible (unless their accounting is quite “creative”)…

    There’s some other dodgy assumptions in that report – assumes zero cost of equity capital (I need some of that!). Hard to tell, but I think they’ve also assumed zero degradation of the battery with cycling.

    Would have been good to have a link to the report in the article (

  8. Sean Thomson 8 months ago

    If only l could go into any of the dozen local new car dealers and ask to see an EV. The sales person would look at me like I have 2 heads. The reason why we don’t buy EVs, is because they’re virtually unavailable.

  9. Graham Moore 8 months ago

    Where is the analysis and regulatory framework for vehicle to grid option. I don’t see any point in buying a battery that is not on wheels. Since I work from home, using the EV to power my home at night except on the odd occasion when I need the extra range seems like the only sensible option. I just can’t find two way charger.

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