The AER released its final Default Market Offer for 2026-27 this week, and the headline looks like good news. Residential electricity prices will fall between 3% and 7% across NSW, South East Queensland, and South Australia from 1 July. Small business prices drop even further. After years of relentless increases, a genuine reprieve.
Don't get comfortable. This is a one-year cyclical dip driven by temporarily lower wholesale costs. The structural forces underneath are all pointing in the opposite direction. And when you do the maths on what the energy transition actually costs, the numbers are sobering.
What the DMO says
⚡ Residential flat rate prices fall 3.4% to 7.2% depending on region
⚡ Small business prices fall further, with some regions seeing reductions above 20%
⚡ The AER attributed the reductions to lower wholesale electricity contract prices, reduced spot price volatility, and increased output from wind and battery generation
⚡ South Australia is the exception, with a modest 1.4% increase for households
So far, so good. But the wholesale cost component is only part of your bill. And everything else is going up.
What's happening underneath
Network costs, the poles and wires that make up 40-50% of your electricity bill, are rising across almost every jurisdiction. The AER has approved network charge increases of around 11% for Endeavour Energy in NSW and 12% for Energex in Queensland. Transmission charges in NSW are jumping from 18% to 21% of network tariffs from 1 July. One NSW commercial customer received a network tariff increase notice of 19.2%, with transmission costs alone contributing 16% of that increase.
This isn't a blip. Australia needs 10,000 km of new high-voltage transmission by 2050, with half required in the next decade. Projects are running three years behind schedule on average and costs are rising fast. Every kilometre of new transmission adds to the regulated asset base and gets passed through to your bill.
ElectraNet in South Australia alone has outlined a $3.94 billion pipeline of priority transmission projects. And that's one state.
The storage maths that nobody wants to talk about
Here's where the conversation gets uncomfortable.
The NEM currently consumes roughly 490 GWh of electricity per day. In winter, with higher heating demand, call it 550 GWh. The grid needs to supply around 25,000-30,000 MW continuously, with peaks hitting 33,000 MW on bad days.
Coal currently provides the backbone of this supply, particularly in the evening when solar is gone and demand peaks. Coal still accounts for around 45% of total generation and a significantly higher share of evening dispatch.
But coal is exiting. Yallourn closes mid-2028. Eraring, the country's largest plant, is now scheduled for April 2029. Vales Point follows. Bayswater goes between 2030 and 2033. By the mid-2030s, more than 80% of the current coal fleet will be gone.
The plan is to replace it with renewables firmed by batteries and backed up by gas. So let's check the maths.
For three days of storage, enough to ride through a cloudy, windless week with minimal renewable generation:
🔋 550 GWh per day x 3 days = 1,650 GWh of storage required
🔋 Current NEM grid-scale battery storage is roughly 6-8 GWh. We need about 200 to 275 times what we have today
🔋 Snowy 2.0, the single largest storage project in Australian history, will deliver 350 GWh. We'd need roughly 5 Snowy 2.0s just for three days of backup
🔋 Snowy 2.0 was budgeted at $2 billion. It's now approaching $30 billion all-in and is only 70% complete after years of delays
🔋 AEMO's own target of 522 GWh by 2034-35 still falls well short of three days
And that's based on today's demand.
The demand bomb
Demand isn't staying where it is. AEMO forecasts NEM consumption rising from 178 TWh in 2024-25 to 229 TWh by 2034-35. That's a 29% increase in a decade, driven by:
🚗 Electric vehicles. Every EV uses roughly 4,000-5,000 kWh per year. Getting to 50% EV penetration adds 40-50 TWh of annual demand, a 25% increase on current consumption. And nearly everyone charges in the evening when solar isn't generating.
🏠 Gas to electric conversions. Victoria alone has 2 million homes on gas. Switching heating, hot water, and cooking to electric adds significant winter load at exactly the time solar output is weakest.
📊 Data centres. AEMO expects data centre demand to reach 12 TWh by 2029-30, about 6% of total NEM consumption, growing to 34.5 TWh by 2049-50. Data centres run 24/7 regardless of whether the sun is shining.
By the mid-2030s, three days of storage at forecast demand levels requires closer to 1,900 GWh. By 2050, when demand has nearly doubled, you're looking at 2,500 to 3,000 GWh.
The replacement problem nobody mentions
Here's the part that really changes the economics.
Grid-scale lithium-ion batteries have a useful life of roughly 10-15 years. Warranties typically cover 10 years to 70% of original capacity. At a grid level, once a battery has degraded to 70-80% of nameplate, it's not fit for purpose in a system that's already short on storage.
That means the entire battery fleet needs to be replaced every 10-12 years.
AEMO's target of 522 GWh of storage by 2034-35, at current grid-scale installed costs of roughly $400,000 per MWh, is approximately $200 billion. For the first build. Then you do it again in the mid-2040s. And again in the mid-2050s.
Over a 40-year period (the operational life of a single coal or nuclear plant), you're replacing the entire battery fleet 3-4 times. The rolling replacement cost alone could reach $600-800 billion before you account for recycling, critical mineral supply pressures, and the installation labour required to rebuild the fleet every decade.
Compare that to AEMO's headline figure of $128 billion for the entire energy transition. That number covers initial capital costs under optimistic assumptions. It excludes battery replacement cycles, financing costs, cost overruns, and distribution network upgrades. The gap between the official estimate and the realistic all-in cost is not small. It's potentially 4-5 times higher.
I've spent 20 years in insolvency. I've seen hundreds of business plans that assumed the best case across every variable. They always end the same way. The $128 billion estimate has the same structural problem. It's not necessarily wrong within its narrow scope. But it leaves out the things that make the real number dramatically larger. And nobody in government appears to be having that conversation publicly.
The coal death spiral
Some people hear all this and ask the obvious question: why not just keep the coal plants running?
Because coal is dying on its own economics, regardless of policy. Solar has permanently destroyed the daytime revenue that coal plants relied on to be profitable over a 24-hour cycle. A coal plant can't just run from 5pm to 10pm. It needs to run continuously. But running continuously means generating into a market where midday prices are zero or negative. So every coal plant is bleeding money for 6-8 hours a day to be available for the 4-5 hours the grid actually needs it.
That's why Eraring's owner wanted to close it early. The NSW government had to offer up to $225 million per year in compensation just to keep it running. Queensland's coal plants failed 78 times last summer. The existing fleet is old, expensive to maintain, and increasingly unreliable.
New coal won't work either. Nobody will finance it. The construction costs are prohibitive. The lead time is 7-10 years. And every major trading partner is implementing carbon border adjustment mechanisms that would penalise Australian exporters using coal-fired electricity.
Coal is going whether we like it or not. The question is what replaces it.
The price shape shift
What's actually emerging is a grid with a fundamentally different price shape.
Daytime electricity is going to be essentially free within a few years. There's so much solar that midday prices will regularly be at or below zero. The AER's new Solar Sharer Offer, which gives households free power from 11am to 2pm, is the first official acknowledgment of this reality.
Evening and overnight electricity is going to get progressively more expensive as coal exits and the cost of firming gets loaded onto those hours. The gap between cheap daytime power and expensive evening power will widen dramatically.
Businesses and households that can shift consumption to the middle of the day will do well. Those that can't, hospitality, retail, manufacturing with evening shifts, anything that operates after dark, will pay significantly more.
Network costs, storage costs, and gas firming costs will be socialised across all consumers, pushing the fixed component of bills higher regardless of when you use power.
What SME owners should actually do
The energy transition is going to be more expensive and more disruptive than anyone in government is willing to admit publicly. The technology to deliver cheap, reliable, low-carbon electricity 24/7 at the scale Australia needs either doesn't exist yet or has been politically ruled out. The alternatives are either unaffordable at scale or unreliable during extended bad weather.
Here's what that means in practice:
- Budget for materially higher electricity costs from FY28 onwards. The DMO cut this year is a cyclical blip. The structural trend is up. If you're energy-intensive, start modelling what your cost base looks like with electricity at double current rates. That's not a worst case. It's a plausible mid-case for the early 2030s.
- Lock in contracts now if you can get a decent deal. The current cycle is favourable for buyers. Wholesale costs are temporarily soft. This won't last once coal plants start closing and gas firming costs escalate.
- Invest in solar if you own your premises and have roof space. Size it to your daytime consumption. The economics of daytime solar generation are genuinely good and getting better.
- Be realistic about batteries. A single unit can help with the evening peak shift. But don't expect batteries to provide multi-day resilience. Factor in the replacement cost every 10 years when calculating payback. And forget about using a home or business battery to charge EVs at scale. The physics don't work.
- Shift what you can to daytime hours. This is the single most valuable operational change most businesses can make. The gap between cheap midday power and expensive evening power is going to become a genuine competitive advantage for businesses that can exploit it.
- Reduce your exposure to the grid where possible. The less dependent you are on grid electricity during expensive hours, the better insulated you'll be from the cost pressures that are coming.
The DMO says prices are falling. For one year, they are. Plan for what comes after.