What happens when you shift your energy use?
Indigo Power’s Managing Director Ben McGowan has put it to the test and written a detailed analysis of his own household energy use to show what the energy transition looks like in practice.
Over the past year, I’ve been talking a lot about how the energy market is changing: higher solar production, lower electricity prices in the middle of the day, and sharper peaks in the late afternoon and evening.
In previous blog posts, I’ve also explained how Indigo Power’s Energy Shapers plan is designed to respond to those shifts. But until now, I haven’t shown what that actually looks like in practice. In this post, I step through the real numbers using my own home as a case study, exploring how changing when and how we use energy affects both my household costs and outcomes for Indigo Power as a retailer.
The house behind the numbers (my house)
This analysis was originally done using my meter data from July 2024 to June 2025, as part of assessing whether to install a home battery under the Federal Government’s Cheaper Home Battery program.
In the background data I have a five-person, all-electric home with two EVs (40 kWh and 77 kWh) and a 5 kW rooftop solar system. The house is on Indigo Power’s Energy Shapers plan (AusNet two-rate NAST11).
Since then, I’ve installed:
- a Sig Energy 10 kW / 40 kWh battery,
- a 12.5 kW DC fast charger (almost double the charging speed of our old charging setup), and
- a pool with a heat pump.
With only 5 kW of solar, and large household consumption, the solar system was never going to be enough to charge a 40 kWh battery. That’s fine, because under Energy Shapers, the battery can be charged from the grid at the right time. In this analysis, we test how the battery would perform charging primarily from the grid.
Two ways to run a battery: self consumption vs co-optimised
A lot of battery conversations are still stuck in an out of date solar story:
- put on lots of solar (because solar feed-in tariffs used to be higher),
- add a smaller battery (because batteries used to be much more expensive), and
- charge the battery from solar that would otherwise be exported, then use it to avoid grid imports in the evening.
That approach is still useful, but it isn’t the only option anymore.
For my house, I couldn’t prioritise more solar right now due to limited available roof space (large sections of the roof needs replacing). I wanted to:
- use low cost daytime grid power when it’s available, and
- invest more into fast EV charging (so we can maximise our use of that cheap daytime energy window).
So we modelled two operating modes:
| Operating mode | What it does | What it’s trying to achieve |
|---|---|---|
| Self consumption | Solar charges the battery; the battery discharges later to cover the home. | Maximise use of your own solar. |
| Co-optimised (grid interactive) | Battery can charge from solar and the grid, and export strategically. | Import when prices are low, reduce imports when prices are high, and export when rewarded. |
How we tested it
Indigo Power’s Analyst, Nick Mason-Smith, used our electricity modelling platform Gridcog to test a range of scenarios using my interval meter data. The first question was simple: If a battery is exposed to the Energy Shapers price signals, what does it choose to do?
The Energy Shapers price signals used in this example
For the specific tariff I’m on in this modelling the relevant tariffs are:
| Price signal | Time window | Rate used in modelling |
|---|---|---|
| Low-cost import window | 10am–3pm | 11.22 c/kWh (effective import rate) |
| High-value export window (feed-in tariff) | 4pm–9pm | 12 c/kWh |
The optimiser responded exactly as intended. It mostly:
- imported/charged during the 10am–3pm window, and
- exported/discharged during the 4pm–9pm window, with some seasonal variation.
What changed in my grid imports and exports?
Here’s what happened to annual imports/exports when moving from “no battery” to a 40 kWh battery operated in a cooptimised way under Energy Shapers.
| Scenario | Annual import (MWh) | Avg import/day (kWh) | Annual export (MWh) | Avg export/day (kWh) |
|---|---|---|---|---|
| No battery | 12.3 | 33.7 | 2.98 | 8.16 |
| 40 kWh battery (cooptimised) | 15.0 | 41.1 | 5.02 | 13.8 |
| 40 kWh battery (self consumption) | 10.1 | 27.7 | 0.47 | 1.29 |
Two simple observations about this analysis:
- Imports increase because the battery is deliberately charging from the grid in the lowcost window.
- Exports only rise slightly because the goal isn’t “export everything”; it’s shifting and shaping flows to reduce costs and improve timing.
So what’s the benefit for the customer?
Financial impact isn’t the only factor, but it’s often the one that determines whether a change happens. Below are the annual bill results across plans and operating modes.
| Scenario | Indigo Power Plan | Annual bill (ex GST) | Saving vs baseline* (ex GST) |
|---|---|---|---|
| Baseline* (no battery) | Community Energy Hub | $3,889 | — |
| No battery | Energy Shapers | $3,587 | $302 |
| 40 kWh battery (co-optimised) | Energy Shapers | $1,547 | $2,342 |
| 40 kWh battery (self-consumption) | Energy Shapers | $2,979 | $910 |
| 40 kWh battery (self-consumption) | Community Energy Hub | $3,246 | $643 |
*Baseline = no battery on the Community Energy Hub plan.
What this shows, really clearly:
- Even without a battery, Energy Shapers improved the outcome in this example.
- With a battery, the big step-change comes when the battery is co-optimised to interact with the grid, not locked into self-consumption mode.
- In this modelling, co-optimised + Energy Shapers reduced the annual bill to $1,547, which is:
- $2,342/year lower than the baseline, and
- $1,432/year lower than running the same battery in self-consumption mode on Energy Shapers.
For a household running two EVs and an all-electric home, that’s a meaningful shift in total cost to live and drive.
What does this mean for Indigo Power Retail?
The key point is that the same behaviour that helps the customer can also help the retailer, and ultimately supports more local energy sharing.
When customers (or batteries) respond to these price signals, it typically means:
- less exporting at times when prices are extremely low or even negative (which is increasingly common in the middle of the day), and
- less electricity we need to supply during the more expensive evening peak, because the household has already charged in the low-cost window.
It doesn’t necessarily mean that we make more money from customers like me when they move from the Community Energy Hub plan to Energy Shapers and add a battery. In my case, it’s the opposite; this is the scenario where we make the least margin.
What it does deliver is lower variability and better predictability. That makes it easier to manage risk, reduce hedging costs over time, and keep prices as sharp as possible for all customers.
Real-world note from my house: fast charging and practical limits
Since the modelling, I’ve made changes that make this approach even more valuable in practice:
- The fast charger means we can shift more EV charging into the cheap daytime window.
- The pool heat pump also runs comfortably in that same window.
In reality, our home often hits a practical constraint. Our connecting to the grid limits how much we can import between 10am and 3pm to a maximum of roughly 55 kWh.
That’s an important reminder that good tariffs only solve one portion of the problem. The real-world wiring, transformer, load constraints, clean energy solution technology and control capability deployed all affect achieved outcomes.
The takeaway
We built Energy Shapers to send clear signals: use more when renewable supply is plentiful, and reward exports when demand is high.
This case study shows that, in my case at least, it’s doing what we hoped, for both the customer and the retailer. For Indigo Power, it reduces load variability, making the load more tractable for risk management. For the customer, it can deliver significant bill savings, especially when a battery is co-optimised to respond to the tariff, rather than sitting in self-consumption mode.
Ben is Indigo Power’s Managing Director. He has a passion for collaborative initiatives that positively impact our communities. Ben leads our skilled and committed projects team, driving the uptake of community-scale clean energy technologies in communities around Australia.