Big Smoke or big battery? How SE Queensland could meet its energy needs from the sun
Dr Philippa England
Oct 3, 2025
Commentary
Solar
Southeast Queensland is rapidly urbanising. By 2046 the region expects to be home to about six million people – about 2.2 million more people than is currently the cas e 1.
Unfortunately, Queensland’s electricity grid is one of the dirtiest in the country – comprising only 26% renewable energy with coal and gas meeting most of the remaining demand 2.
So, does the growing population of Southeast Queensland mean the region is destined to become (if it isn’t already) the Biggest Smoke in the dirtiest State in the country?
Only if we let that be the case! Happily, the alternative is sitting at our door – or more precisely, on our rooftops, in our garages and in the gold-plated poles and wires running between them all.
The facts speak for themselves. As of 2019 Queensland had an estimated 37 GW of potential rooftop capacity of which, at that time, about 6% (2.35 GW) was harnessed for solar production 3.
The same report identified Brisbane, Gold Coast, Sunshine Coast, Moreton Bay and Logan as areas with the most solar rooftop potential in the whole of Australia 4.
Six years on from 2019, SEQ now hosts around 3.5 GW of rooftop capacity 5 capable of generating approximately 15 GWh of power per day (on average) or 5,475 GWh per year 6.
Our rooftop solar power is forecast to continue growing at a rate of 10% per annum, meaning by 2032 we are likely to have around 7 GW of installed rooftop solar in SEQ and by 2039 we will be up to 14 GW of rooftop solar.
At that point, our rooftops will be generating more electricity than we currently draw from the grid (21,687 GWh of electricity per annum) 7. If, instead of 10%, we were to grow our capacity at 15% per annum, that situation could be reached in just ten years.
That’s not an unrealistic scenario given the imminent end of the legacy feed-in tariff rate for early adopters (in 2028) coupled with the growing size of new rooftop arrays (averaging over 10KW). No wonder our energy providers are getting nervous.
Of course, not all rooftop solar power gets exported to the grid and, with the increasing affordability of household storage, more rooftop solar is likely to remain behind-the- meter.
Nevertheless, the sheer size of our potential rooftop capacity (37 GW across Queensland in 2019) means there is more than enough capacity to meet SEQ’s demand for electricity both behind-the meter (in the homes and buildings where it is generated) and in front of the meter (in the low voltage, distributed network).
And the good news doesn’t stop there. In addition to SEQ’s vast rooftop potential, we now learn the region has the most underutilised capacity of any distributed network in the NEM. Energex estimates there is 12 GW of spare capacity available for use at zero or insignificant extra cost in its low-voltage, distributed network 8.
An additional 4.3 MW could be accommodated at a “low” cost of $400,000 per MW. This means, if managed well, there is already enough space in our local network to accommodate up to four times our existing rooftop solar 9.
All this means, if we seize the moment, SEQ could meet all its daily energy needs with clean, renewable rooftop solar power 10.
So, what’s the catch? Two things – first, to maximise our use of rooftop solar we need enough storage to ensure our abundant – but variable – solar power is available across the day and night whenever people need to use it. In short, we need to better match our supply of solar power with our demand for electricity. Secondly, we need the political will to make it happen.
Let’s explore the easier challenge first: matching solar supply with electricity demand.
The two available strategies here are (a) to rapidly increase our storage capacity so solar power generated in the middle of the day can meet demand across a 24-hour period; and (b) to use more power during the day when solar production is at its peak and less at night, when solar power can only be supplied via batteries. Obviously, the better we get at option (b) the less of option (a) will be needed.
A recent report by Ember demonstrates the feasibility and cost effectiveness of a 24-hour solar strategy in sunny locations around the world based on adequate solar and storage 11.
Its research shows an even supply of power across a 24-hour period will need something in the order of 3.5 kwh of battery storage for each kw of rooftop solar capacity 12.
Many domestic, commercial and retail activities use less power after 9.00 pm so a less ambitious goal might be in the order of triple our rooftop solar capacity – perhaps 42 GWh of storage to spread 14 GW of rooftop solar capacity across the day and night.
From a current baseline of less than 1 GW of big battery storage in operation across the whole of Queensland 13, that is a gargantuan task. Is it an impossible one?
We should take heart from the Cheaper Household Battery Scheme, which has installed 760 MW in just two months 14. The average size of those installations has already jumped to 20KWh.
If Queensland’s existing 1 million solar rooftops each installed 20 KWh of storage, cumulative household storage capacity would amount to 20 GWh of storage capacity. That would be a huge cost saving for 1 million rooftop owners and a big dent in the gargantuan task of marrying up our solar with storage.
But, given most of that stored power is likely to remain behind-the-meter, we will still need more storage – a lot more. Big batteries, such as the Brendale Big Battery just outside Brisbane, will and are, capable of doing a lot of the heavy lifting.
Welcome as these big batteries are, the success of the Cheaper Household Battery Scheme reminds us the quickest, smartest and most impactful solutions – at least in terms of reducing customers’ bills – activate Consumer Energy Resources (CER).
The biggest opportunities are with EV owners and the C&I sector. SEQ now has the highest rate of growth in EV uptake across the nation 15. With almost 50,000 EVs already driving around Queensland here is an existing opportunity to store, manage and share up to 3 GWh of battery capacity.
If Queensland decision-makers are looking for a fast, low-cost energy strategy, they should be engaging with EV owners and the C&I sector to incentivise the purchase and sharing of stored energy capacity.
Appropriate technology is already available but, as things currently stand, the cost-benefits to CER owners are not easily demonstrable. Tariff signals will be central to unlocking these latent storage opportunities.
The obvious – but often forgotten – alternative to storage is load shifting, that is, flexing our demand for power to match the times of day when it is most abundant and cheap. A recent report from the ANU demonstrates the potential cost savings of load shifting on a citywide scale 16.
It found the electrification of homes and transport could send demand soaring by more than 30 per cent and put fresh strain on rapidly changing grids.
Alternatively, by shifting just half of the flexible load identified in the study to off-peak hours, projected increases to peak demand could be halved, removing the need for costly grid upgrades and making better use of abundant rooftop solar resources 17.
In Queensland, where rooftop solar power is already a major player, load shifting means using more power in the middle of the day when solar production is at its peak.
To incentivise load shifting, Energex has recently introduced a solar sponge tariff rate involving zero network charges for transmission between the hours of 11.00 am and 4.00 pm.
If that tariff rate is effectively passed on to consumers (including good communication strategies), they will no doubt choose to fill their batteries (to the extent their rooftop solar isn’t doing it for them) in those midday hours whenever they can.
All well and good for stationary batteries permanently connected to the grid but what about our growing number of EVs parked at work? The sheer scale of Queensland’s current duck curve (involving up to 3,400 MW of curtailed renewable energy in the middle of the day) 18 suggests every strategy in the book is required.
Support for inexpensive Level 2 charging (7-22 kw per hour) at every workplace destination should be a no brainer. It should be welcome news, for example, to see the 2025 draft National Construction Code (NCC) reforms propose requirements for destination charging in commercial premises. 19
Sadly no. The Regulatory Impact Statement on the 2025 NCC reforms assessed this proposed requirement would incur a net cost to the community and should therefore be considered separately (if at all).
Meanwhile, the current Queensland Government – always eager to slash and burn red tape – is considering advice from the Queensland Productivity Commission that even the existing energy efficiency standards in the NCC should be relaxed and any new standards should be stalled.
These cost-benefit, economic assessments are too narrowly construed. They do not, for example, consider the cost to the community of augmenting the NEM to cater for EV charging at peak evening times or the service to the grid provided by load shifting midday peak solar supply.
A more holistic assessment is required. When charging at work is as convenient and as affordable as charging at home, the huge cost benefit to the SEQ grid of load shifting at scale will become achievable 20.
In Queensland, thanks in large measure to Energex’s solar sponge tariff, the price of electricity in the middle of the day is often very low, zero or even negative.
That means, if destination charging devices can access wholesale prices, EV owners will literally be able to get paid for charging their car at work regardless of whether they have access to solar at home. Surely, it doesn’t get better than that?
If the Queensland Government wants a sensible, least cost energy transition out of coal (eventually) with less uptake of wind power generation (for whatever reasons) it would do well to look seriously at the role that rooftop solar already plays in Queensland – and its huge scope to ramp up even more in cost-effective ways that benefit the consumer, the grid and the budget.
At the last election, the LNP’s federal counterpart missed the challenge and paid the price. Will the Crisafulli Government do better than that?
Dr Philippa England is an Adjunct Senior Lecturer at Griffith University (GLS).- SEQ Regional Plan, p.11. planning.statedevelopment.qld.gov.au ??
- https://www.stanwell.com/info-hub/article/how-queensland-can-reach-80-per-cent-renewable-energy-by-2035 ??
- Institute for Sustainable Futures et. Al, How much rooftop solar can be installed in Australia, 2019, Report prepared for Clean Energy Finance Council and Property Council of Australia, p.22 cefc.com.au ??
- Institute for Sustainable Futures et. Al, How much rooftop solar can be installed in Australia, 2019, Report prepared for Clean Energy Finance Council and Property Council of Australia, p.22 cefc.com.au ??
- Energex Revised Regulatory Proposal 2025-2030, p.49 aer.gov.au ??
- In Queensland 1kw of solar panel generates 4.5-5.4 kw per day on average. ecoflow.com ??
- Energex Revised Regulatory Proposal 2025-2030, p.48 aer.gov.au ??
- AEMO, Electricity Network Options report 2025, p.190 aemo.com.au ??
- AEMO recommends a two thirds utilisation rate. AEMO, Electricity Network Options report 2025, aemo.com.au ??
- Excluding dunkelflaute situations. ??
- https://ember-energy.org/latest-insights/solar-electricity-every-hour-of-every-day-is-here-and-it-changes-everything/ ??
- https://ember-energy.org/latest-insights/solar-electricity-every-hour-of-every-day-is-here-and-it-changes-everything/ ??
- https://reneweconomy.com.au/big-battery-storage-map-of-australia/ ??
- Noting the Cheaper Household Battery Scheme is on track to install approximately 4 GW of household battery storage across Australia in 12 months. See: reneweconomy.com.au ??
- https://www.aaa.asn.au/research-data/electric-vehicle/ ??
- https://reneweconomy.com.au/evs-and-electric-hot-water-can-transform-cities-into-giant-batteries-to-slash-peak-demand/
Lu et al., City-scale integration of distributed energy storage resources for an all-electric energy future, (2026) Renewable Energy 256(B)
sciencedirect.com
?? - https://reneweconomy.com.au/evs-and-electric-hot-water-can-transform-cities-into-giant-batteries-to-slash-peak-demand/ ??
- https://reneweconomy.com.au/sunshine-state-enjoys-highest-ever-rooftop-solar-output-and-record-levels-of-renewable-curtailment/#:~:text=That%20translated%20also%20into%20a,growth%20in%20rooftop%20PV%20capacity. ??
- Centre for International Economics (CIE), Increasing the Stringency of the commercial building energy efficiency provisions in the 2025 National Construction Code. Consultation Regulatory Impact Statement, Final Report, 2024, p.5. ??
- Lu et al., City-scale integration of distributed energy storage resources for an all-electric energy future, (2026) Renewable Energy 256(B)
sciencedirect.com
reneweconomy.com.au |
