Solar Victoria’s marketing department wanted to spruik their solar battery rebate. Did they choose to mislead or inform the public?
On the 16th of January 2020 Solar Victoria published what they called a “case study” under the Latest News section on their web site. It’s about a person who is happy with their new solar battery system. On the face of it, that seems a lot better than someone who is unhappy with their battery system, but I suspect the person who bought it may have been misled and won’t be so happy with their purchase after they learn the truth.
I put quotation marks around the words “case study” because:
- It did not present information that would enable readers to either check the strongly implied conclusion, or draw their own conclusions, as I expect a case study to.
- Rather than a case study, it appears to be an advertisement for household batteries paid for by the Victorian Government with public money.
What I find most troublesome about their “case study” is that it may break Australian Consumer Law1. I believe Solar Victoria should investigate to determine if a breach of Consumer Law has occurred and, if so, consult with Victorian Consumer Affairs to help remedy the situation. What they should not have done is turn it into an advertisement for an overseas battery manufacturer at the Victorian taxpayer’s expense.
It’s A Tesla Powerwall 2
The battery system is a Tesla Powerwall 2. We can tell because it’s in the photograph at the start of the ad. Here’s how the “case study” starts:
Yep, that’s definitely a Tesla Powerwall 2 there. I know because it says…
T followed by [Japanese symbol for the number 3] followed by S, followed by L, followed by [Symbol for either a table or the Qi Dynasty or possibly a table owned by the Qi Dynasty.]
…on the front and no one is installing counterfeit batteries in Victoria. Especially not as part of Solar Victoria’s battery rebate, which will knock up to $4,838 off a solar battery’s price. This is, if you get in before the 1,000 available rebates run out and live in the right area. A list of the 40 eligible postcodes can be found here.
I want to be clear there is nothing in the ad that suggests there is anything wrong with the Tesla Powerwall 2 itself. I expect it’s working just fine. But even if the battery is working perfectly it’s not capable of doing what the ad suggests unless there are very special circumstances that are not explained.
The “Case Study”
I’ve put the body of the advertisement or case study or whatever it is below. I have circled a few things I find troublesome according to the following colour code:
- Green for environmental concerns,
- Blue for a couple of things that don’t seem to add up when considered together, and…
- Red for a financial concern I consider to be circumstantial evidence Australian Consumer Law has been broken.
Green Concerns
Unfortunately, at this time, batteries don’t reduce emissions. They increase them. This is because each time a battery is charged and discharged there are unavoidable losses. A Powerwall 2 can only provide around 88% of the energy that is put into it.2 This means clean solar energy exported directly to the grid reduces fossil fuel generation by more than storing it in a battery for later use.
Because batteries very rarely store clean energy that would otherwise go to waste, at the moment they are a net environmental negative.3 I go into the details in this article if you’re interested. The main exception is if a home is export limited and produces solar energy that otherwise would go to waste if it wasn’t stored in a battery.
Green Statements & Consumer Law
Australia’s Consumer Guarantees state, among other things, that products must:
- Be fit for the purpose the business told you it would be fit for and for any purpose that you made known to the business before purchasing.
So if the company that sold Janelle the solar battery told her it would benefit the environment then they may have broken Australian Consumer Law — unless they pointed out it would only help under specific conditions. The same goes if Janelle told them she wanted a battery for environmental reasons and they didn’t tell her it wasn’t suitable for that purpose.
Fortunately, I generally don’t see solar battery sellers making environmental claims about their products. For example, I can’t see any on the Tesla site about the Powerwall 2. Because of this I’m hopeful no one was misled in this regard.
Blue Concerns — Average Energy Use
I circled a couple of phrases in blue because they make me concerned about the battery owner’s household energy use:
If I was talking to a friend about their Powerwall 2 and they told me they use loads of energy — often in the middle of the night — I would assume this means they frequently use all the stored energy in their battery overnight. This is a good thing from the point of view of getting the solar battery to pay for itself.
But if the next thing they told me was that in a major blackout they should have power for two days, I’d have to stop them and make sure they knew what they were talking about. If they are often draining their battery overnight then they’re not going to have power for two days. They’re only going to have it for one night. And I’d make sure my friend understands they are often not going to have a full battery charge when a blackout strikes. If they are using it to minimize their electricity bills as much as possible, when the grid goes down it may have less charge than a balloon that’s been rubbed against a bald kitten.
It’s possible my friend has this all figured out and has set their Powerwall 2 to always reserve some energy for emergencies and has a plan to ration it out over two days with the assumption skies will be overcast and rooftop solar output low. (A reasonable precaution as blackouts are more likely to occur during stormy and wet weather.) But they would have to explain that to me so I’d know they understand how their Powerwall 2 works. Without an explanation I wouldn’t know what they were thinking.
Solar Victoria’s advertisement or “case study” or whatever it is, should make it clear exactly what the homeowner is thinking. This is because at the moment it leaves me thinking she may have been misled about how her battery works.
Red Concerns — It Won’t Pay For Itself In 3 Years
My most serious worry is where Solar Victoria quotes Janelle as saying:
I’m concerned because that’s just not going to happen. A fully installed Powerwall 2 is likely to cost at least $16,000. The Solar Victoria rebate will only knock $4,838 off that, so she’s likely to have paid over $11,000 for it.
Using our Electricity Retailer Comparison Tool, I see there are electricity plans available in Victoria that charge around 21.2 cents per kilowatt-hour and have a solar feed-in tariff of 12 cents. This means the 13.5 kilowatt-hours of electricity a fully charged Powerwall 2 can supply will only reduce a home’s electricity bill by $2.97.
But the savings won’t be that much because, with an efficiency of 88%, to charge it with $2.97 worth of electricity will require 15.34 kilowatt-hours of solar electricity. With a solar feed-in tariff of 12 cents this means the household will forgo $1.84 in feed-in tariff. So instead of reducing the electricity bill by $2.97, the energy in a fully charged Powerwall 2 will only reduce it by $1.13.
If the Powerwall 2 is fully charged with solar electricity every day and fully discharged every night and doesn’t suffer any capacity deterioration, then it will save $412 a year. After 3 years it will have saved $1,236. As $1,236 is less than the $11,000 or more that was paid for it, it definitely won’t pay for itself in 3 years.
Even with the Victorian battery rebate and a low total cost of $11,000, it would take 26 years and 8 months for it to pay for itself. That’s nearly 9 times longer than 3 years the advertisement suggests and far longer than its maximum warranty of 10 years.
In reality, the Powerwall 2 will not be fully charged and discharged every day and its capacity will slowly deteriorate, so the actual savings will be less and the payback period longer. Probably much longer.
Having a time-of-use tariff does not change things much. Firstly, because the financial benefit is not large even if stored electricity is only used during peak periods, as they aren’t available on weekends. And secondly, if the only reason you are on a time-of-use tariff is because you have a solar battery, then the proper comparison to work out how much you are saving is the standard tariff you would be on if you didn’t have a battery.
Maybe there are some special circumstances I am not aware of, such as membership in an amazing Virtual Power Plant I don’t know about with high payments that makes batteries an awesome investment, but that is definitely something Solar Victoria should have mentioned.
Was Australian Consumer Law Broken?
I’m sitting here wondering, “Where did Janelle get the idea her Powerwall 2 would pay for itself within 3 years from?” Maybe she made the estimate herself and made a mistake, since most people aren’t familiar with calculating solar battery payback, or maybe she was misled.
Australian Consumer Guarantees state that products must:
- Match descriptions made by the salesperson, on packaging and labels, and in promotions or advertising, and…
- Meet any extra promises made about performance, condition and quality, such as lifetime guarantees and money back offers.
If she was told by salespeople the battery would pay for itself in three years then Australian consumer law has been breached, as that’s not going to happen. As a result, Janelle is entitled to a remedy, which in this case is likely to be a refund.
What Solar Victoria should have done when they became aware of this “case” is investigate whether or not Australian Consumer Law had been broken, not turned it into an advertisement for batteries. Since they did turn it into an advertisement, they should now work to undo the potential harm they have caused to Victorians and others by making sure people understand that, unless there are very strange circumstances, a battery is not going to pay for itself within 3 years.
If they don’t take action to correct the harm they have caused, to both the public and the solar battery industry, people may start to suspect they don’t have the best interests of Victorians at heart.
We all know that batteries are going to play a large and important part in our clean energy future. But that doesn’t make it OK to mislead the public about battery performance and payback in order to shift some slow-moving solar battery rebates.
Footnotes
- Caveat: I’m not a lawyer – but this is my strong opinion! ↩
- Tesla says the Powerwall 2’s round trip efficiency is 88%. Not all Powerwall 2s do this well, with the exact efficiency probably depending on where they’re located and how they’re used. But looking online and from what people have told me, 88% doesn’t appear uncommon, so I will use this figure. ↩
- If you want to argue that by installing batteries you are creating a grid where more solar and wind capacity are likely to be built, you would be right. But it is an expensive way to go about encouraging clean energy when the money could be instead be spent directly on rooftop solar or improved efficiency such as insulation or replacing an internal combustion engine car with a hybrid or EV. ↩
About Ronald Brakels
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“If you believe it, then it’s not a lie” – G. Castanza
I’m very much pro-Tesla*, but entirely agree with your perception, Ron. It’s impossible the Powerwall 2 could pay for itself in three years.
While Janelle may have been misled, it’s irresponsible of Solar Victoria to perpetuate this myth.
For the next three days, I’m working on a submission addressing my concerns about Synergy’s ongoing policies and practices in withholding FiT rebates from our female tenants. It’s interesting that _only_ female tenants have suffered this abuse. All male applicants have been paid the full 47.135c / kWh, without fuss or delay.
* A TSLA shareholder in fact!~
Well she could have enough power for two days IF she had a decent sized solar system and if the sun was shining – in fact she could have enough power for a week or more depending on the weather and if she moderates energy use during a blackout period.
For the most part your article is spot on but I do think you need to amend the following:
“And secondly, if the only reason you are on a time-of-use tariff is because you have a solar battery,”
Actually if you have solar panels put on the utility will generally put you on TOU and a smart meter. So unless you get a battery without solar that’s inaccurate, at least in my experience.
Yes, it depends where you are, but that certainly can happen.
I agree with you but why don’t you forward this to consumer affairs instead of just blogging about it?
Consumer affairs generally only listens to complaints from consumers otherwise there would be a lot of potential for businesses to abuse the system by making complaints about their competitors.
How confident are you in the $16,000 installation figures?
My recent solar install cost me just shy of $3500 and that included 72 cell Mono Panels in Landscape on a difficult roof and a hot water timer. $3k is common.
Last I looked, your site (a great source of Technical information) recommends spending upwards of $6,000. Nobody has been able to explain what extra I would have gotten if I had spent an extra $3k.
A quick search shows Materials Costs ~$12k and a Standard install @ $1k. This gets us $3k closer to the goal.
Over here in Perth, we are on 28c in/7c out with a system capped @ 5 kW total if you want to get paid for what you put back in the grid.
My Inverter is in limit for roughly 4 hours per day, squandering potential generation, so that my electrical company can keep running their gas turbines during the day..
My 3kW A/C runs all night in peak summer. A great application for battery tech. Charging a Hybrid vehicle when you get home is another good one.
Don’t get me wrong, the Economics aren’t there yet, but with electricity prices on the rise and the future value of money on the decline, the gap is closing.
Here at work we have a 10 kW surplus that we give to our energy provider for free. Whilst it is good for the environment, the Economics of running a Server and Security system 24/7 make batteries more attractive.
Oh, Yeah,
Western Power say that you can’t run your house off batteries or solar during an outage if you are connected to the grid. A linesman needs to be able to safely isolate a section.
That said, I recon there may be a market niche for a device that isolates the grid in times of blackout, so that a PV/Battery system can continue to operate, whilst maintaining safety for electrical workers.
Cant tell if your trolling or not, maybe its a Perth sense of humor.
How confident are you in the $16,000 installation figures?
– That’s the price of a TESLA 2 Powerwall + install (can be be 1k to 2k as there is special connection and configuring on those, you’ll also be waiting longer than a month.
My recent solar install cost me just shy of $3500 and that included 72 cell Mono Panels in Landscape on a difficult roof and a hot water timer. $3k is common.
Again your just describing panels and an inverter, with your $figure and the current rebate I can assume that’s a 4.5 to 5.5kw system.
Last I looked, your site (a great source of Technical information) recommends spending upwards of $6,000. Nobody has been able to explain what extra I would have gotten if I had spent an extra $3k.
– your confusing costs on PV arrays and batteries, however a decent solar array costs at min $6k that 6.6kw (e.g; Tier 1 panels Jinko and a Fronius Inverter).
A quick search shows Materials Costs ~$12k and a Standard install @ $1k. This gets us $3k closer to the goal.
-Is’ that a Mining joke? Elon would like to speak with the source! who provided you with the exact materials and the costs involved to build a TESLA 2 battery.
Over here in Perth, we are on 28c in/7c out with a system capped @ 5 kW total if you want to get paid for what you put back in the grid.
My Inverter is in limit for roughly 4 hours per day, squandering potential generation, so that my electrical company can keep running their gas turbines during the day..
-….What? I have re read this multiple times, is this relation to: $ value you make on return investment aka being paid by your Electricity resale? Your daily production/ use with the solar array vs whats going into the grid? not sure what electrical company and their turbines have to do with this.
My 3kW A/C runs all night in peak summer. A great application for battery tech. Charging a Hybrid vehicle when you get home is another good one.
– Yes Defiantly a Perth Person recommending using a Solar battery storage to run an AC, genius.
Don’t get me wrong, the Economics aren’t there yet, but with electricity prices on the rise and the future value of money on the decline, the gap is closing.
-Value of money doesn’t decline, share values, resources values and currency’s values rise and fall depending on the share market.
Here at work we have a 10 kW surplus that we give to our energy provider for free. Whilst it is good for the environment, the Economics of running a Server and Security system 24/7 make batteries more attractive.
-10KW surplus, needs more context, is that from 13KW system you have and the left over 10KW in surplus, or is that a 100kw system with 10kw in surplus?
Running anything like a Server and Surveillance system on batteries is hilarious!
Oh, Yeah,
Western Power say that you can’t run your house off batteries or solar during an outage if you are connected to the grid. A linesman needs to be able to safely isolate a section.
– well they lied, that’s incorrect information. You can run off your own solar anytime iunless there is no sunlight. for the batteries you described the SA battery rebate scheme which requires your batteries be available encase of black or brown outs.
That said, I recon there may be a market niche for a device that isolates the grid in times of blackout, so that a PV/Battery system can continue to operate, whilst maintaining safety for electrical workers.
– Like circuit breakers, kill switches and battery/ PV isolates.
….and apparently YOU’RE confusing conceptions with reality. ( “– your confusing costs on PV arrays and batteries, however a decent solar array costs at min $6k that 6.6kw (e.g; Tier 1 panels Jinko and a Fronius Inverter”) For example, even ebay has Jinko panels for under 50 cents per watt, (and have been cheaper) sans rebate. Your other assertions are equally unrealistic, based upon the automatic assumption that a “TESLA 2 Powerwall + install” is the necessary standard. It’s not.
Apparently Powerwall 2 can combine with panels and run your home while islanded.
This is correct. Here in Canberra, I specifically asked both Solarhub and EvoEnergy to confirm this important detail. In the event of a blackout, the Powerwall2 will supply power to the home’s circuits to which it is wired. I reckon this means one needs to be a bit strategic in making sure the best choice of home circuits is selected as the PW2 can only deliver 5kW.
Personally I wouldn’t use TESLA products in a off-grid circumstance, aka no power from the grid. They can d it, but their not efficient and lacking the grind connection have been known to act up. In a pinch for an hour or 2 a TESLA should suffice just about anyone. As long as your not trying to run a 3kw AC like “Tim” else you would be out of power before the mains come back on.
Tim, you should add 10% GST to the 28c+/kwh tariff in Perth. That makes it over 31c/kwh versus 7c FIT.
To be fair, Solar Victoria says: https://www.solar.vic.gov.au/solar-battery-rebate
“Installing a battery can help a typical household save up to $640 a year”
Note “up to”
Anyone telling a prospective customer any battery will pay for itself in 3 years is lying unless there are some truly amazingly unique circumstances. An end user who thinks they are getting a 3 year payback possibly needs a new calculator.
Promoting any $figure values on savings is dangerous and reckless regardless of the application. If you cant grantee promised $figure and that you will make up the difference if that $figure isn’t met then its a lie and your scamming which is a federal offence.
3 years! ROFL!.. maybe they are using that “optimisation software” that one company is spruiking! Anyway the devil is always in the detail and if you buy a battery only option (i.e you already have solar) then there are very very very few instances where a battery install on its own will pay itself back within the Warranty period.
Hey Ron
Can you clarify the arrangements for solar/battery use during a blackout? I am of the understanding that I cannot use the power during a blackout (and have had that experience) due to concerns about electricity company workers isolating the lines for safety ….
So, unless I am isolated from the grid (ie, no FIT or backup power from the grid), then I cannot operate my home devices during a blackout regardless of sunshine or batteries. I am in NSW, so the SA agreements do not help me (but how does that work there?).
Hi Steve
Rooftop solar and/or batteries have to be isolated from the grid during a blackout to protect line workers. But the right battery system will isolate your home from the grid automatically, allowing the battery to be used. Some battery systems, such as the Powerwall 2, let your home use power from rooftop solar during the blackout while others don’t.
As long as you have a system that isolates you from the grid there is no problem using batteries in a blackout.
Thanks, Ron
Does that work for NSW as well? I have heard – but do not have the reputable source to quote – that this is not allowed in NSW?
steve
In all states homes have to be isolated from the grid before they can use batteries in a blackout, but provided that happens there is no problem using a battery during a blackout in NSW. Just note that not all battery systems are capable of isolating the home from the grid, if not will will shutdown in a blackout.
How wonderful that the Vic Government can force us retailers to adopt the CEC approved retailer code of practice in order to take part in the Solar Homes rebate scheme, yet they contravene the very rules of the code by falsely advertising battery performance and payback. No chance that Tesla Powerwall can be paid back in 3 years.
Also batteries will have a positive environmental impact when connected micro-grid technology reaches the level where coal fired power stations can be throttled way back or even taken off line.
I think there should be a way to harness the static electricity from that cat. Imagine if everyone in the world who owned a cat could rub it with a balloon and then store that somehow we would have a solution to the world’s energy. Then we could move to huge cat farms – millions upon millions of rows of cats with automated robots rubbing balloons on their backs.
Mind you, there’d probably be some very disgruntled cats but a small fortune to be made producing kitty litter.
Top people are working on this:
Tesla powercat. Coming in 2021. 2 year payback period.
Nope. That whole section about “Green Concerns” is baloney. Your line of thinking implies that the reason people install batteries is to prop up the grid and because of the round-trip inefficiency of batteries, this process is therefore net negative for carbon.
But seriously, who does that? The system I am about to install will provide my household load first and foremost. The battery will be designed to ONLY charge by solar and never by mains (why would you?) The mains will be used as last resort, only when the battery depth of discharge forces the issue. Therefore, the ONLY carbon-based energy I will use will be last resort. The 88% efficiency would only matter if I was somehow emitting CO2 to in order to charge the battery (that is, charging from the grid.)
Equally, I will never export from my battery to the grid. Again, why would I? I need to keep that energy in reserve for a rainy day.
OK, so if I get several cloudy days and import from the grid? Well, I’m certainly not responsible for more emissions that I would have been before I got the battery, am I?
No what the author is referring to is the extra CO2 generated from charging the battery from solar. Its the lost reduction of emissions from the grid in total because you are not exporting. The author is essentially correct. Its not good for the environment, you lose money, the government loses money and charges more taxes or reduces expenditure on more important services. Its a lose lose lose lose situation.
Its a bit counter intuitive but if you did not have a battery you would export to the grid. Every bit you export reduces the demand for coal and gas generation on the entire grid. Since the battery does not generate but consumes (12% if you have a good system) without a battery you would be exporting up to 100%.
Its a bit harder to quantify than the author indicates however IMO because its hard to quantify if your exports reduce the generation by 100% of that amount or some lower amount or if line losses equal more than 12%.
But in general considering the emissions involved with battery manufacture and the environmental costs associated with the mineral mining its virtually impossible for a battery in this country to be even carbon neutral unless you live in a house that cannot be connected to the grid.
If you live in a house that could be connected to the grid and do not connect that is even worse for carbon emissions because all your excess generation goes to waste and you need more batteries.
I wonder if the problem is one of semantics. The author uses the language of economists to refer to a foregone environmental benefit as a cost. For example, if a government policy resulted in a forecast increase in GDP of $1m and not implementing the policy would increase GDP by $1.1m, they would say it cost $0.1m. Personally, I don’t equate foregone revenue with a cost. To me a cost means there is less money in my bank account at the end of the day compared to the beginning of the day as opposed to a smaller increase.
If you install PV and a battery, there is no way I can see that ‘costing’ the environment although I can understand the argument that the environmental benefit from not installing the battery might be higher still.
If you weren’t charging your battery with your PV system, the assumption is all of the energy would go into the grid. More importantly, the author assumes that energy added to the grid is balanced by a reduction in fossil-fuel generation of electricity.
I think, though, that the discussion is over-simplified in that it neglects time-of-use versus time-of-generation. I know from detailed study of 10 years of personal time-of-consumption data that between 30 and 75% of my demand occurs during off-peak (30%) and shoulder (40-45%) periods. My panels produce 16-20% of their daily output during the peak demand period of (0700-0900, 1700-2000) and the remainder during the first shoulder period (the middle of the day).
What this means to me is that until I find a way to time-shift my generation to match my demand, my peak and shoulder demand are adding a load to the grid that is definitely being met by burning gas and coal. If I install a Powerwall 2, for example, it will comfortably meet my domestic electricity load (10.8 kWh/day) during the day and thereby eliminate my demand for grid power entirely.
The question is: are there more emissions associated with meeting my peak and shoulder demand using fossil fuel combustion compared to the roughly 2 kWh of PV-generated electricity consumed to charge/discharge the Powerwall (15% of 14 kWh for a full charge) so that I can eliminate my grid demand entirely. I imagine the answer depends on additional factors such as grid congestion (how much large scale renewable power is crowded out of the grid by residential solar, for example).
Regarding embedded energy and associated emissions in the manufacture of Li-ion batteries, recent work by Swedish (Nov 2019) and Argonne National Lab (ANL) estimate 61-106 kg CO2-e per kWh of battery capacity. This is a substantial decrease in this value since 2017 and is based on better data from larger-scale manufacturing facilities studied by ANL. For a Powerwall 2 with 14 kWh nameplate capacity, this gives an upper bound of 1484 kg CO2-e per powerwall 2 which is equivalent to 1484 kWh of coal-fired electricity (the 61 value comes from the use of cleaner energy sources in the manufacturing process). The 1484 kWh of embedded energy is equivalent to 110 full charge/discharge cycles of 13.5 kWh. As I understand life cycle analysis, this implies that after 4 months, the system has recovered the energy of manufacture and the next 9 years and 8 months are gravy (in CO2 terms). But I get muddled with LCA so please feel free to correct my misunderstandings.
I am not persuaded by the author’s position that efficiency is superior to eliminating demand for grid power. If all my energy is 100% renewable, efficiency is irrelevant to the climate, although it may remain relevant to your personal finances!
You are totally correct. Your household CO2 emissions will go down if you only consider the usage in your home and ignore all others.
But if you don’t have a battery the Total Emissions of your house, battery production plus reduction of emissions in the grid due to the export will be greater.
Therefore your house will be less but overall emission to the atmosphere will be greater if you get a battery because you are reducing your emissions reductions in the grid (plus the manufacture CO2) more than if you just installed panels. This does assume as the author assumes that your exports reduce co2 emissions in the grid. I have no idea if that is true or the excess is just wasted but as there is no time of the day when the grid is in total supplied only by “green energy” and the shortfall is always made up by fossil fuels this means any reduction in grid production should mean a reduction in fossil fuel production.
When or if the total supply of green energy is greater than demand in the grid then excess supply from solar needs to be stored or wasted. Then the entire situation changes and a battery will make more environmental sense.
In the mean time you cost yourself money and don’t improve the overall emissions from the society in total.
Let’s look at this another way. If everybody decided to not install batteries, then their peak period demand will be met by burning fossil fuels. If everybody installed PV + battery at a size that fully supplied their local consumption, then no GHGs would be emitted apart from the embedded emissions in the manufacturing of the battery, so in my example above this a small amount of emissions for 3 months followed by 9.75 years of zero emissions.
I am only considering personal residential use here.
Someone has to go first. Early adopters help the industry bring down the unit cost so that others can eventually afford to adopt technology. If everyone waited for someone else to go first, nothing will happen.
We still haven’t resolved the question about the actual difference in emissions with and without batteries. If residential export to the grid exacerbates marginal loss factors of large scale renewable generators (I have no idea if this is the case, bnut I know MLFs have become an important concern for large scale generators) then installing a battery will not displace renewable energy with FF energy, instead it will simply replace a renewable contribution from a small scale generator with one from a large scale generator.
I imagine there are also important considerations related to smoothing out grid demand, i.e. reducing the amplitude of the ‘duck’s back’. Less variability in the grid demand from shoulder to peak to off-peak periods would presumably impact on the efficiency of operation of the FF plants that are called on to provide generation that cannot be supplied by renewables. My understanding is that large thermal plants work better the less they have to be cycled between on and off and spinning reserve. I would be very interested to learn how emissions from the FF generators change depending on the time-variability of grid demand.
Yesbut. Whilst everybody includes the “If everybody installed PV + battery at a size that fully supplied their local consumption, then no GHGs would be emitted apart from the embedded emissions in the manufacturing of the battery” clause they seem to overlook the “embedded” cost(s) of building, installing and maintaining of the power-stations and other grid components. Such factors (including the various costs of running power retailers) are quite separate from the cost(s) of actually producing the GHG-producing electricity distributed by the grid.
I have no numbers to provide, but strongly suspect that such costs would far outweigh the ’embedded costs’ of providing stand-alone battery-banks all round.
“Because batteries very rarely store clean energy that would otherwise go to waste, at the moment they are a net environmental negative. … The main exception is if a home is export limited and produces solar energy that otherwise would go to waste if it wasn’t stored in a battery.”
I suspect this exception may well be the rule. My system in inner Melbourne shuts down several times a day due to voltage overload. This means that power I could potentially export to the grid is being lost. Maybe it is power that is not needed at that time of day, but if I had a battery I could store it for my own use.
Not disputing your other arguments about costs, embodied energy etc however
This is a pretty ridiculous claim: “Unfortunately, at this time, batteries don’t reduce emissions. They increase them. This is because each time a battery is charged and discharged there are unavoidable losses.”
It would be more accurate to say that Solar does not reduce emissions. There is so much renewable capacity (esp. SA & QLD) in the daytime that for most of the 25 year life of your solar system, you will just be displacing large scale solar wind that gets curtailed as a result.
A battery will displace far more fossil fuel electricity during is life because it discharges when RE% is low in the grid, while solar generates when RE is/will be close to 100% in the grid anyway.
Get your facts straight.
Hi Rob
In the future batteries will be able to reduce emissions by storing clean renewable energy that would otherwise go to waste, but even in South Australia with the highest wind and solar penetration in Australia, clean renewable electricity rarely goes to waste because production is curtailed, as electricity can be exported to Victoria. As curtailments of renewable generation increase then the environmental benefit of battery storage will increase.