10 ms·

Wait, capped at 24 kWh a day? Our household consumed 8 kWh per day over the past week (gas cooking, no airco). So with a home battery that sinks 10 kWh during t

Wait, capped at 24 kWh a day? Our household consumed 8 kWh per day over the past week (gas cooking, no airco). So with a home battery that sinks 10 kWh during those 3 hours you have minimal energy costs?

thedays 2mo ago
Yes - the regulated offer is capped at 24 kWh per day but some retailers such as Globird and CovaU are offering plans which include up to 50 kWh per day of ‘free’ electricity. With a large enough battery and inverter you could just end up paying daily supply charges of $1.65-2.20 per day.
- rsanek 2mo ago
  Critically, that cost excludes the amortized amount the batteries will be over that period. And if you're cycling them every day like this, they're not going to last more than 15~20 years.
  - adrianN 2mo ago
    Cycling 50kWh of batteries daily seems like a very unusual level of consumption.
    - Schwolop 2mo ago
      I'm in Australia, with Globird, and have their 3hrs free plus they pay $1 on days I don't use any grid power between the 6-8pm peak, and another $1.50 if I send them back 10kWh of the energy I was given for free during the day, during that peak. In winter, with bugger-all solar (maybe 5kWh generation if I'm lucky) I pull 10kW/hr into a 40kWh battery for those 3hrs each and every day, while also running the heating as high as possible to gain some thermal battery effect too. That 30kWh of battery charge is used up by late evening or middle of the night by fully-electric heating (RCAC split systems and a large ducted RCAC system), so the battery goes down to 5% where I stop using it except in the case of grid failure, and back up to ~75% each day. The idea that no one uses more than 24kWh of electricity each day is absurd - not only will I pull 30kWh to charge a battery, I'll also pull another ~30 or so just to keep warm. My house could easily use 100kWh per day if we heated it to a pleasant level instead of a warm-enough level. The main problem, as Australians are no doubt aware, is that our houses are large and poorly insulated. I've done everything sensible already (ceiling + floor insulation, draft sealing, honeycomb blinds, etc) except paying $100,000 to double-glaze all windows, and it still feels like a tent. Despite all this ranting, electricity is now effectively free in summer for me, and ~$5-8 per day in winter. Pre-battery it was in the ballpark of $10-25 per day. The battery should have a payback period of 4 years, but was heavily subsidized by the government. Due to how I'm charging and discharging it so regularly, I'm expected it might only have a 10yr lifetime.
  - wolrah 2mo ago
    > And if you're cycling them every day like this, they're not going to last more than 15~20 years. You can't make a blanket statement like that because it depends on a lot of variables about their specific battery system and power needs. If you have just enough battery to get through a normal day so you're running them top to bottom every day then sure, those are likely to have a relatively short life. If you've set up your system with extra capacity to support extended total grid outages and/or bad weather now your normal days might only be cycling from 80% down to 60% and back. Of course battery chemistry is also relevant, and a home battery system doesn't need to care about energy density or peak charge/discharge rates in the same way an EV might. On top of all that, now that we're over 15 years in to mass-produced EVs we've learned that our battery life expectations were generally pessimistic. As long as the batteries are kept within a reasonable temperature range and not otherwise abused they tend to be in pretty good condition even this far in to their expected service life. Home energy storage systems are a lot easier on batteries than automotive use so as a general rule they should last even longer even with similar cycle counts.
som 2mo ago
Forget 3hrs free. We lived in the tropics in Australia with a ~6kW system and often had negative quarterly invoices (i.e. got paid by our retailer) ... esp. in winter months. Aircon, pool, appliances all electric. At the very least the pool pump ran free all year round. Edit: should add, that's straight solar no battery
- throwaway2037 2mo ago
  > often had negative quarterly invoices (i.e. got paid by our retailer) ... esp. in winter months "[I]n winter months"? My stupid northern hemisphere brain did a double take; I needed to remind myself that Christmas (December) is summer!
  - cmoski 2mo ago
    It's got nothing to do with the hemisphere. Most likely the aircon is running less in winter so they don't use as much power. There is not much of a winter in the tropics.
    - som 2mo ago
      Sorry should have been clearer, in winter there's no aircon (but also no heating, it's 20-25 deg c) and the pool pump runs approx 50%
    - dostick 2mo ago
      It is winter right now.
      - cmoski 2mo ago
        Yes, but it's nothing like winter further from the equator. It's a lovely time of year in that part of the world.
  - cutterl6 2mo ago
    Winter is the cold one down here too mate
canpan 2mo ago
Just for reference our fully electric household (including cooking, water and aircon). Highest usage this month on a very hot day was 25kWh. (Disclaimer: I am not in Australia. Already cover most of it with roof solar. No battery yet)
rulesilol 2mo ago
I pay about 38c per kilowatt plus $1.70 per day for the connection fee. So by that maths, you'd save 8×0.38=$3.04 per day. A 10kWh battery is in the ballpark of $4000. So it'll take about 4 years to break even. Then you'd just have to pay the connection fee, which seem to be increasing every year.
- pixl97 2mo ago
  >which seem to be increasing every year. In general inflation is increasing everywhere so not completely unexpected. Also solar/battery powered networks are shaped differently than ones only powered by prime movers. The edges become thicker as power becomes generated at the edge.
- Panzer04 2mo ago
  The connection fee would also rise with less energy consumption/free electricity to amortize the fixed costs of the power grid.
  - markvdb 2mo ago
    Not necessarily. At least in Flanders (northern ~half of Belgium), this was shifted onto consumers by making them pay for peak quarter consumption. Using more than 2.5kW for 15 minutes in a row on average means you pay a lot more for your fixed grid cost.
    - upsuper 2mo ago
      Australian grids are already talking about removing all per-kWh tariff and shift all the cost to fixed supply fee. The government rejected it probably because it doesn't make them look good, and it makes poor people pay more. But it's probably just time before that comes.
- gib444 2mo ago
  > $1.70 per day for the connection fee A sneaky tax that keeps rising. In the UK it pays for failed energy companies, people defaulting on their energy bills, energy bill subsidies... and supposedly for grid upgrades lol It's risen far above inflation (responding to a sibling comment)
reyoz 2mo ago
This is what I am doing. 42 kWh battery, 6 kW solar and fully electrified house, 2x EVs. I am able to charge cars at work and so in the depths of winter I am able to run the house by charging during the 3 hour window. There have been just a couple of cold (~2-4 degC) days when the battery was depleted 1-2 hours before the window starts. As the weather warms and we get more solar exposure we will easily be in excess. We get a very small export rate with a bonus for no energy consumption during peak evening hours which can offset the fixed daily charge. There are a lot of gotchas that you need to be aware of. 42 kWh is nominal capacity not the actual usable capacity. House load, max grid import and export capacity, max inverter capacity, AC or DC coupled panels, battery charging profile, battery temp are all factors in how much you can charge in the window. For example I have max 15 kW grid draw, with a 10 kW inverter that can charge the battery. I can put in max ~30 kWh into the battery, so I also run other loads in the house to use the other 5 kW capacity. If I go over 5 kW house load the battery charge is clipped to maintain grid import limit.
- throwaway2037 2mo ago
  > I am able to charge cars at work Nice perk! Does you know who pays for the electricty? Is this "virtue signalling" by the company or landlord... or a subsidy from the local/state/national gov't? To be clear, I am not making any value judgement about providing free charging for EVs. It seems like good gov't policy to promote the adoption of EVs.
  - freshpots 2mo ago
    It costs $5-$10 for the electricity to charge a car using level 2 charging. It is a trivial "perk" for an employee that costs an order of magnitude more per hour of work.
    - yandie 2mo ago
      [dead]
    - pjc50 2mo ago
      Never mind that, the cost of an urban parking space is considerable. Here's a £50k London parking space: https://www.rightmove.co.uk/properties/136662200#/?channel=RES_BUY https://www.rightmove.co.uk/properties/136662200#/?channel=R... While that's an extreme, I would expect the cost of any urban parking space with a low speed charger to be dominated by the land, then the charger one-off install price, and thereafter electricity use is a pretty trivial cost. Sydney will also charge you 3,000 $AUS annually for central parking spaces: https://www.revenue.nsw.gov.au/taxes-duties-levies-royalties/parking-space-levy/understanding-parking-space-levy/levy-rates-and-calculations https://www.revenue.nsw.gov.au/taxes-duties-levies-royalties...
AnotherGoodName 2mo ago
Quite simply put this is what they ask you to do. To the point that the Australian government will heavily subsidise (30%) home battery installation. Remember Australia has over 10x the rollout of solar than china (per capita of course). It’s not hard to achieve this for any competent government. Bluntly China’s government is corrupt and inefficient (usa is even further behind china since their current government is also corrupt and inefficient). This rollout of cheap solar in Australia is causing power prices during a global energy crisis and a datacenter build out to plummet. And fwiw i don’t think Australia’s government is perfect. But it should set the bar to other nations of ‘what could be’. You could have falling power prices right now if you enabled a government to encourage what is currently by far the cheapest form of electricity (solar).
- murderfs 2mo ago
  You're right, China should stop selling solar panels to Australia and deploy them internally.
  - anakaine 2mo ago
    They have been mass deploying solar and battery. They also realise that they can make profit from export markets because internal supply capacity exceeds internal demand.
- asdefghyk 2mo ago
  RE "......what is currently by far the cheapest form of electricity (solar)....." this is misleading and wrong. At best it is a half true statement. My total power bill has not decreased. Solar electrity may be cheap to produce. However if only generates for 4-5 houra day, generates non at night or bad weather. May generate non for several days in bad (cloudy weather ) So the supply of reneables (solar ) is un reliable. To make renewables (solar ) reliable , we need big (grid size) batterys. For the grid we need new transmission lines. Predicted to be 10,ooo KM for Austrlia. Cost of new transmission network, last estimate i saw was $40 Billion AU The government mandated smart meters will allow peoples power supply to be turned off when the likely power shortages occur.
- 2mo ago
Tuna-Fish 2mo ago
The Australian grid presently curtails ~7-18% of production every single day between 11:00 and 14:00. I believe that incentivizing people to acquire batteries is precisely the purpose of the policy. It's good for the grid for there to be a lot of storage at the edges. As I understand it, the 24kWh cap is subject to annual review, with it being reduced/the policy being soft phased out once curtailment is no longer necessary.
- markvdb 2mo ago
  The core of the EU system is much more elegant. It sets a day-ahead production price per 15 minutes at auction. In EU countries with reasonable distribution cost, dynamic rates are a quite popular way to shift consumption to when cheap electricity is abundant.
  - upsuper 2mo ago
    Australia has that as well, the wholesale market changes price every 5 minutes, but it is a big ask for average consumers to follow that price and shift power usage in real time.
    - RossBencina 2mo ago
      > it is a big ask for average consumers to follow that price and shift power usage in real time. I could imagine appliances that take that into account. e.g. an airconditioner that works harder during the cheaper periods. I wonder whether any retailers pass through the 5 minute pricing variation? Should be easy enough to monitor the price and adjust my AC via the infra red remote protocol.
      - Swannie 2mo ago
        Down to 15 minutes, yes, retailers exist, if you have a smart meter (which are 4G connected for near-real time data back to the grid and retailer).
      - upsuper 2mo ago
beAbU 2mo ago
An ev charging at 7kw will consume 21 of the 24kWh. Now, if you don't drive massive distances every day then this might not be the best deal, but I can see how this might be worth it for someone commuting 200km a day for example. Taxi drivers, and the like will also probably benefit.
AndrewDavis 2mo ago
While I can't speak for other states (though I'd be surprised if they were different), power bills in Victoria are split into supply and usage. Eg each day costs 90c, then 30c per kw/h. So you could eliminate the usage costs, but not the supply charge. The whole reason for this is Australia's power grid is a market, where suppliers put in bids for how much they can produce, and at what price. And AEMO then selects the cheapest way to meet demand (paying the marginal price), but also expects residential rooftop solar a given. As a result we often have an excess of power driving wholesale pricing into the negatives. The free power is a way to increase usage at times when we're most likely to have negative pricing, and encourage use of high energy appliances like dishwashers etc to be run during that period to reduce demand the rest of the time.
manarth 2mo ago
Given that energy prices are negative during this period (because of surplus solar which needs to be drained into a load to keep the grid balanced) – this is effectively consumers providing "free" balancing-services to the grid. With sufficient take-up and consumers funding the cost of battery storage, this could replace an amount of commercial balancing services and reduce the overall cost of grid-management.

thedays 2mo ago

Yes - the regulated offer is capped at 24 kWh per day but some retailers such as Globird and CovaU are offering plans which include up to 50 kWh per day of ‘free’ electricity. With a large enough battery and inverter you could just end up paying daily supply charges of $1.65-2.20 per day.

rsanek 2mo ago
Critically, that cost excludes the amortized amount the batteries will be over that period. And if you're cycling them every day like this, they're not going to last more than 15~20 years.
- adrianN 2mo ago
  Cycling 50kWh of batteries daily seems like a very unusual level of consumption.
  - Schwolop 2mo ago
    I'm in Australia, with Globird, and have their 3hrs free plus they pay $1 on days I don't use any grid power between the 6-8pm peak, and another $1.50 if I send them back 10kWh of the energy I was given for free during the day, during that peak. In winter, with bugger-all solar (maybe 5kWh generation if I'm lucky) I pull 10kW/hr into a 40kWh battery for those 3hrs each and every day, while also running the heating as high as possible to gain some thermal battery effect too. That 30kWh of battery charge is used up by late evening or middle of the night by fully-electric heating (RCAC split systems and a large ducted RCAC system), so the battery goes down to 5% where I stop using it except in the case of grid failure, and back up to ~75% each day. The idea that no one uses more than 24kWh of electricity each day is absurd - not only will I pull 30kWh to charge a battery, I'll also pull another ~30 or so just to keep warm. My house could easily use 100kWh per day if we heated it to a pleasant level instead of a warm-enough level. The main problem, as Australians are no doubt aware, is that our houses are large and poorly insulated. I've done everything sensible already (ceiling + floor insulation, draft sealing, honeycomb blinds, etc) except paying $100,000 to double-glaze all windows, and it still feels like a tent. Despite all this ranting, electricity is now effectively free in summer for me, and ~$5-8 per day in winter. Pre-battery it was in the ballpark of $10-25 per day. The battery should have a payback period of 4 years, but was heavily subsidized by the government. Due to how I'm charging and discharging it so regularly, I'm expected it might only have a 10yr lifetime.
- wolrah 2mo ago
  > And if you're cycling them every day like this, they're not going to last more than 15~20 years. You can't make a blanket statement like that because it depends on a lot of variables about their specific battery system and power needs. If you have just enough battery to get through a normal day so you're running them top to bottom every day then sure, those are likely to have a relatively short life. If you've set up your system with extra capacity to support extended total grid outages and/or bad weather now your normal days might only be cycling from 80% down to 60% and back. Of course battery chemistry is also relevant, and a home battery system doesn't need to care about energy density or peak charge/discharge rates in the same way an EV might. On top of all that, now that we're over 15 years in to mass-produced EVs we've learned that our battery life expectations were generally pessimistic. As long as the batteries are kept within a reasonable temperature range and not otherwise abused they tend to be in pretty good condition even this far in to their expected service life. Home energy storage systems are a lot easier on batteries than automotive use so as a general rule they should last even longer even with similar cycle counts.

som 2mo ago

Forget 3hrs free. We lived in the tropics in Australia with a ~6kW system and often had negative quarterly invoices (i.e. got paid by our retailer) ... esp. in winter months. Aircon, pool, appliances all electric. At the very least the pool pump ran free all year round. Edit: should add, that's straight solar no battery

throwaway2037 2mo ago
> often had negative quarterly invoices (i.e. got paid by our retailer) ... esp. in winter months "[I]n winter months"? My stupid northern hemisphere brain did a double take; I needed to remind myself that Christmas (December) is summer!
- cmoski 2mo ago
  It's got nothing to do with the hemisphere. Most likely the aircon is running less in winter so they don't use as much power. There is not much of a winter in the tropics.
  - som 2mo ago
    Sorry should have been clearer, in winter there's no aircon (but also no heating, it's 20-25 deg c) and the pool pump runs approx 50%
  - dostick 2mo ago
    It is winter right now.
    - cmoski 2mo ago
      Yes, but it's nothing like winter further from the equator. It's a lovely time of year in that part of the world.
- cutterl6 2mo ago
  Winter is the cold one down here too mate

canpan 2mo ago

Just for reference our fully electric household (including cooking, water and aircon). Highest usage this month on a very hot day was 25kWh. (Disclaimer: I am not in Australia. Already cover most of it with roof solar. No battery yet)

rulesilol 2mo ago

I pay about 38c per kilowatt plus $1.70 per day for the connection fee. So by that maths, you'd save 8×0.38=$3.04 per day. A 10kWh battery is in the ballpark of $4000. So it'll take about 4 years to break even. Then you'd just have to pay the connection fee, which seem to be increasing every year.

pixl97 2mo ago
>which seem to be increasing every year. In general inflation is increasing everywhere so not completely unexpected. Also solar/battery powered networks are shaped differently than ones only powered by prime movers. The edges become thicker as power becomes generated at the edge.
Panzer04 2mo ago
The connection fee would also rise with less energy consumption/free electricity to amortize the fixed costs of the power grid.
- markvdb 2mo ago
  Not necessarily. At least in Flanders (northern ~half of Belgium), this was shifted onto consumers by making them pay for peak quarter consumption. Using more than 2.5kW for 15 minutes in a row on average means you pay a lot more for your fixed grid cost.
  - upsuper 2mo ago
    Australian grids are already talking about removing all per-kWh tariff and shift all the cost to fixed supply fee. The government rejected it probably because it doesn't make them look good, and it makes poor people pay more. But it's probably just time before that comes.
gib444 2mo ago
> $1.70 per day for the connection fee A sneaky tax that keeps rising. In the UK it pays for failed energy companies, people defaulting on their energy bills, energy bill subsidies... and supposedly for grid upgrades lol It's risen far above inflation (responding to a sibling comment)

reyoz 2mo ago

This is what I am doing. 42 kWh battery, 6 kW solar and fully electrified house, 2x EVs. I am able to charge cars at work and so in the depths of winter I am able to run the house by charging during the 3 hour window. There have been just a couple of cold (~2-4 degC) days when the battery was depleted 1-2 hours before the window starts. As the weather warms and we get more solar exposure we will easily be in excess. We get a very small export rate with a bonus for no energy consumption during peak evening hours which can offset the fixed daily charge. There are a lot of gotchas that you need to be aware of. 42 kWh is nominal capacity not the actual usable capacity. House load, max grid import and export capacity, max inverter capacity, AC or DC coupled panels, battery charging profile, battery temp are all factors in how much you can charge in the window. For example I have max 15 kW grid draw, with a 10 kW inverter that can charge the battery. I can put in max ~30 kWh into the battery, so I also run other loads in the house to use the other 5 kW capacity. If I go over 5 kW house load the battery charge is clipped to maintain grid import limit.

throwaway2037 2mo ago
> I am able to charge cars at work Nice perk! Does you know who pays for the electricty? Is this "virtue signalling" by the company or landlord... or a subsidy from the local/state/national gov't? To be clear, I am not making any value judgement about providing free charging for EVs. It seems like good gov't policy to promote the adoption of EVs.
- freshpots 2mo ago
  It costs $5-$10 for the electricity to charge a car using level 2 charging. It is a trivial "perk" for an employee that costs an order of magnitude more per hour of work.
  - yandie 2mo ago
    [dead]
  - pjc50 2mo ago
    Never mind that, the cost of an urban parking space is considerable. Here's a £50k London parking space: https://www.rightmove.co.uk/properties/136662200#/?channel=RES_BUY https://www.rightmove.co.uk/properties/136662200#/?channel=R... While that's an extreme, I would expect the cost of any urban parking space with a low speed charger to be dominated by the land, then the charger one-off install price, and thereafter electricity use is a pretty trivial cost. Sydney will also charge you 3,000 $AUS annually for central parking spaces: https://www.revenue.nsw.gov.au/taxes-duties-levies-royalties/parking-space-levy/understanding-parking-space-levy/levy-rates-and-calculations https://www.revenue.nsw.gov.au/taxes-duties-levies-royalties...

AnotherGoodName 2mo ago

Quite simply put this is what they ask you to do. To the point that the Australian government will heavily subsidise (30%) home battery installation. Remember Australia has over 10x the rollout of solar than china (per capita of course). It’s not hard to achieve this for any competent government. Bluntly China’s government is corrupt and inefficient (usa is even further behind china since their current government is also corrupt and inefficient). This rollout of cheap solar in Australia is causing power prices during a global energy crisis and a datacenter build out to plummet. And fwiw i don’t think Australia’s government is perfect. But it should set the bar to other nations of ‘what could be’. You could have falling power prices right now if you enabled a government to encourage what is currently by far the cheapest form of electricity (solar).

murderfs 2mo ago
You're right, China should stop selling solar panels to Australia and deploy them internally.
- anakaine 2mo ago
  They have been mass deploying solar and battery. They also realise that they can make profit from export markets because internal supply capacity exceeds internal demand.
asdefghyk 2mo ago
RE "......what is currently by far the cheapest form of electricity (solar)....." this is misleading and wrong. At best it is a half true statement. My total power bill has not decreased. Solar electrity may be cheap to produce. However if only generates for 4-5 houra day, generates non at night or bad weather. May generate non for several days in bad (cloudy weather ) So the supply of reneables (solar ) is un reliable. To make renewables (solar ) reliable , we need big (grid size) batterys. For the grid we need new transmission lines. Predicted to be 10,ooo KM for Austrlia. Cost of new transmission network, last estimate i saw was $40 Billion AU The government mandated smart meters will allow peoples power supply to be turned off when the likely power shortages occur.
2mo ago

Tuna-Fish 2mo ago

The Australian grid presently curtails ~7-18% of production every single day between 11:00 and 14:00. I believe that incentivizing people to acquire batteries is precisely the purpose of the policy. It's good for the grid for there to be a lot of storage at the edges. As I understand it, the 24kWh cap is subject to annual review, with it being reduced/the policy being soft phased out once curtailment is no longer necessary.

markvdb 2mo ago
The core of the EU system is much more elegant. It sets a day-ahead production price per 15 minutes at auction. In EU countries with reasonable distribution cost, dynamic rates are a quite popular way to shift consumption to when cheap electricity is abundant.
- upsuper 2mo ago
  Australia has that as well, the wholesale market changes price every 5 minutes, but it is a big ask for average consumers to follow that price and shift power usage in real time.
  - RossBencina 2mo ago
    > it is a big ask for average consumers to follow that price and shift power usage in real time. I could imagine appliances that take that into account. e.g. an airconditioner that works harder during the cheaper periods. I wonder whether any retailers pass through the 5 minute pricing variation? Should be easy enough to monitor the price and adjust my AC via the infra red remote protocol.
    - Swannie 2mo ago
      Down to 15 minutes, yes, retailers exist, if you have a smart meter (which are 4G connected for near-real time data back to the grid and retailer).
    - upsuper 2mo ago

beAbU 2mo ago

An ev charging at 7kw will consume 21 of the 24kWh. Now, if you don't drive massive distances every day then this might not be the best deal, but I can see how this might be worth it for someone commuting 200km a day for example. Taxi drivers, and the like will also probably benefit.

AndrewDavis 2mo ago

While I can't speak for other states (though I'd be surprised if they were different), power bills in Victoria are split into supply and usage. Eg each day costs 90c, then 30c per kw/h. So you could eliminate the usage costs, but not the supply charge. The whole reason for this is Australia's power grid is a market, where suppliers put in bids for how much they can produce, and at what price. And AEMO then selects the cheapest way to meet demand (paying the marginal price), but also expects residential rooftop solar a given. As a result we often have an excess of power driving wholesale pricing into the negatives. The free power is a way to increase usage at times when we're most likely to have negative pricing, and encourage use of high energy appliances like dishwashers etc to be run during that period to reduce demand the rest of the time.

manarth 2mo ago

Given that energy prices are negative during this period (because of surplus solar which needs to be drained into a load to keep the grid balanced) – this is effectively consumers providing "free" balancing-services to the grid. With sufficient take-up and consumers funding the cost of battery storage, this could replace an amount of commercial balancing services and reduce the overall cost of grid-management.