Opposition leader Peter Dutton’s assumptions about home battery performance could do with some tweaking.
In a doorstop interview on Wednesday in Brisbane and in reference to Minister for Climate Change and Energy Chris Bowen, Mr. Dutton said:
“He wants you to throw out your gas oven, he wants it to be replaced with an electric oven. The electric oven, unless you’re using the oven through the day and you’ve got solar panels, if you’re using the oven of a night-time it’s going to be running off fossil fuels because the battery lasts about 45 minutes. It doesn’t get you through the hours of darkness.”
How big is the oven and how small is the battery Peter Dutton based this assessment on? And was this also a half-hearted attempt to create kerfuffle with an Australian version of the USA gas stove ban hoax?
Electric Oven Vs. Home Battery
We don’t have a solar battery yet and we don’t use our electric oven very much, opting to use a microwave and air-fryer mostly for that sort of work as there are significant electricity savings to be had by doing so. But I checked the power rating for our electric oven, and according to the label:
So, 2.56kW. This means over an hour of use the oven will consume a maximum 2.56kWh. But that’s only if the element is constantly on, and that’s not how electric ovens work in practice. Once the oven reaches the desired temperature, the element switches off for a bit until the temperature drops enough that it needs to kick in again.
But for the sake of this argument, let’s call it 2.56kWh for that hour of use, including warm-up time.
Now let’s look at a popular home battery – the Tesla Powerwall. It has a usable capacity of 13.5kWh. This means a fully charged Powerwall could run our oven for around *5 hours*. It’s not a great use of a home battery if there are other options, but it points to the “about 45 minutes” claim as whiffy at best.
On the SQ solar battery comparison table there are a bunch of home batteries available in Australia with 10kWh+ capacities. Where there are products with quite low capacities, these are usually modular systems intended to host multiple units in situations where an energy consumption profile requires more capacity.
Glass Houses And All That
Something else Peter Dutton said in response to the same question eliciting the home battery performance claim that needs to be called out again:
“The government was elected with a policy to reduce your power prices by $275,” said Mr. Dutton. “The Prime Minister promised it on 97 occasions and he’s never mentioned that figure or that promise once in the eight or nine months since he’s been elected. So, I just make that very important point.”
PM Albanese may be regretting that commitment even if Labor still has a couple of years to make good on it given the way retail electricity prices have been tracking. Considering world events at the time and with a bit of probing, Labor could have exposed what was actually going to occur (in the reasonably short term anyway) no matter who was in power and perhaps gracefully re-jiggered this; as tricky as it may have been.
This is another “very important point” – there was a trap waiting.
The Liberals’ own electioneering right up to just days before the 2022 federal election stated “we are now turning the corner on power prices” – meaning things were looking good. They were anything but and given the circumstances, I suspect the Morrison Government had at least a pretty solid heads- up about it.
Peter Dutton’s predecessor was well known for pushing alternative interpretations concerning energy and related topics. For example, back in 2019 Scott Morrison said Labor’s embracing of electric vehicles would “end the weekend”. This statement didn’t make SQ’s Ronald’s subsequent “Top 10 EV Myths” article because, as Ronald put it:
“it was too stupid to make the cut.”
If Peter Dutton is trying to differentiate himself from Scott Morrison, he may be going the wrong way about it as it’s starting to sound like more of the same.
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SQ leans Left, so is the problem Dutton’s assumptions, or politics?
Re: the statement, & thanks for the transcript link (orig. sources are best), it was in response to a question about Labor’s approach to power prices, gas prices being at worst case scenario heights, and Hume saying it’s yet another broken promise.
Dutton said the promise to reduce power bills by $275 was made on 97 occasions prior to the election, & never since Labor took power. Labor had a budget & claimed to have a plan in October, but all we’re seeing is rising energy costs & ever increasing costs of living. All indisputable so far.
Coalition policy at the time was, & is, that more power needs to be generated as increased supply = lower prices i.e. basic economics. Dutton stated Bowen wants gas ovens abolished & replaced with electric, which leads into the SQ quibble – that using an electric oven rather than gas at night means using fossil fuel power, & batteries only last 45 minutes.
Is that claim incorrect, or mere exaggeration? Per SQ figures (2.5kWh x 3/4hrs) for a battery to run flat you’d be relying on a ~1.8 kWh model. Does such exist?!?!? isn’t the smallest model sold a 4kWh?
3 possibilities spring to mind. SQ’s view is Dutton is lying or ignorant about batteries &/or electric ovens. But maybe he knows, at least generally, the average battery size & average overnight energy use, but is exaggerating for effect. Or perhaps there’s unspoken assumptions that underpin the figures e.g. AC (~4 kWh) + lights & TV (~0.5 kWh) + electric oven (2.5 kWh). Even a 13.5 kWh Tesla Powerwall would only support 1 hour of oven use, & ~2 hours with everything else before reliable (fossil fuel) grid power kicks in.
Ending with criticism of the Morrison Government, & Dutton for sounding akin, is veering into political power not electrical power which is what SQ is respected for. Differences in political views are tolerated, but if SQ opts to push partisan politics their credibility will crumble.
By my calcs, it costs about $913.00 for 10kWh per night for a year of power currently https://www.ergon.com.au/retail/residential/tariffs-and-prices/compare-residential-tariffs#:~:text=A%20time%20of%20use%20tariff,between%209am%20to%204pm%20daily.
If it costs $17990.00 installed for a Tesla Powerwall 2, it will take 20 years to pay for itself. Good luck with it lasting that long. Govt’s batteries will be no different, the taxpayer will end up paying.
And that’s before people start plugging in Electric Vehicles which can take up to 76kWh to fully charge. Try that overnight with batteries…
And yes, I live off grid, and it’s not cheap.
Recently installed a Solar Edge Battery and added to my existing solar panels. The panels had already paid for themselves after 3 years (had calculated 4 years). With the new battery we can effectively live ‘off grid’ and now only export for a feed in tariff. Don’t buy power now. By my conservative calculations the battery should pay for itself in 10 years. However with electricity prices increasing that pay back time fame will likely decrease.
And yes we own an EV with a 80kwh battery. Charge it using excess solar using the Charge HQ app. No issues for past 12 months. No one charges EVs with house batteries … except maybe Peter Dutton .
Would you mind sharing your “conservative calculations”, because mine don’t go anywhere near what you are describing.
Lucky that I got my Tesla Powerwall 2 for $11754 fully installed with full house backup. No subsidies or rebates.
It’s 5 years+ old now, so, the battery is well through its halfway warranty period.
Battery is capacity is 97.55% (down to 13.169kWh from 13.5kWh in 2017). So, it has lost almost 2.5% of its original battery storage capacity over 5 years. Not bad. Warranted to be 70% capacity at the 10 year mark….. Hard to predict how much it will lose over the next 5 years.
But I’ve already recovered the payback period (blended payback of solar and battery systems combined). Battery by itself does not recover itself, it needs solar to complement it.
I’ve averaged about 75% self-powered per year. I’ll never get to 100% self-powered due to heating in winter (over 90% of annual grid import is for winter use). Unless I switch to gas for heating/cooking/hot water which I don’t want to as the expense to switch is not worth it as that expense can pay for my grid connection and imports anyway. I treat the grid as my backup. No need for a genny and having to deal with messy diesel.
It seems that your costs are a bit dated and/or over the top.
I live in Darwin so everything here is rated to terrain category 4, cyclone proof, and I recently had 6kw of panels, inverter and 12 kWh battery installed for $12,000. Normal domestic use with oven, microwave and steamer in the kitchen 2 reverse cycle air cons – this is the wet season – and there was 1.5% of battery left this morning.
System is programmed to use battery first and reduce imported power but I do want to know how to program it to fill battery and keep it filled so that in the event of a sustained power outage, that cyclone stuff again, lights and fridge will keep running.
Quite right, Craig. And despite the clever quotes/assumptions there’s another one that’s been completely overlooked: “There are lies, damned lies, and statistics” . Numbers can be made to say anything. I put my first solar system up in 1983 ($13.80 per Watt for the panels alone!) and have used it (solar-power)almost the whole time since (ie 40 YEARS) in all sorts of situations and conditions. Needless to say one learns to balance things out, rearrange methodologies/priorities, etc. (eg, I’ve always preferred deep-cycle AGM L/A batteries for assorted reasons*; one being that one can get them cheap and they’re virtually bomb-proof. Mine ( 200ah in a bank of up to a dozen @ no more than $1.80 per ah: and plenty of 2nd-hand ones available for free when you find your way around.) usually last 4/5years. AND even then they’re able to be rejuvenated to some degree.) I wouldn’t even consider an electric oven. Even with a massive battery-bank you’d kill your batteries in about a fortnight. (A slow-combustion stove not only cooks/bakes, but also produces our hot-water and heats the living area at the same time.) I DO like the microwave, which runs at 1600W, so having half a brain I set up a remote-start switch for the car and run a cable from the garage to the kitchen via a 2400W inverter, for five minutes at a time. The point is you can innovate your way through anything: AND at the right price. That includes carrying 2x200ah units in the back of the van hooked into the ignition system just in case. Wouldn’t want to et caught with my prejudices down. All the best.
ps *Another being that I don’t REALLY want to burn my house down with charging lithium!
Hi,
My wife likes to use the oven (electric ~2400W) in the day time, that way she can relax at night after dinner. Roasts are usually started mid afternoon. In winter, or really cloudy days, it runs just fine off our batteries (solar panels are connected). We can even run the kettle at the same time (~2000W). Dutton is FOS.
dRdoS7
I’ve had panels for 14 years and a battery for 8 months.
By monitoring the battery Gen/Load/Feed-in/Grid consumption data, I’ve been able to get a pretty good idea of individual power consumption for appliances down to a hot water kettle.
Here is what I know:
1. The biggest user is hot water. Put a timer on it so that PV generation heats it. In winter, it will need some battery power but try and get some power from the PV. (A heat pump will be installed when the induction heater dies.)
2. Second big user is the stove. Use a microwave, air fryer or old fashioned pressure cooker in preference. They use less than a quarter of the power required to heat a big box and then cook food..
3. Turn the a/c on earlier so it uses PV power to start cooling the house. Then it will progressively use less and less when the sun comes off the roof. Set the a/c at 24C.
4. My 10 kWh battery has supplied 98.7% of my total power needs – measured over 8 months which included the wettest July/August on record for the Sydney area.
5. After two consecutive rainy fully overcast days when my PV is only producing 30-35% (yes, PV does produce when the sun don’t shine. That is another furphy.); we’ll use a small amount of grid power to top up.
On balance, I’m very pleased with my set up. It is working as I designed and I look forward to at least 10 years of essentially zero grid consumption. The risible feed-in “return” should pay for the soon to be increased Access Charge. That should see a payback period of almost 9 years. The key is avoided cost by self-use.
Dutton demonstrates, yet again, the dangers of listening to uninformed fools. Btw when I was considering my first PV set-up, in 2009; I remember listening to Alan Jones stridently warning about “doing my dough on this rubbish”. Thankfully, I ignored his “sage” advice and solar has been one of my better investment decisions.