When a solar system is installed, it changes the way your electricity account operates. While solar is designed to reduce the amount of electricity you purchase from the grid, it can also influence how your electricity pricing is calculated by both retailers and network providers.
1. Reduced Grid Consumption and Cost Allocation
Electricity pricing is made up of several components — not just the energy you consume. A significant portion of your costs come from fixed network, retail, and market charges.
These include:
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Network costs (for using the poles and wires that deliver power)
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Retail service fees (administration, billing, metering, and compliance costs)
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Market participation and environmental charges (set by regulators or government schemes)
These costs don’t decrease simply because you’re using less grid energy — they are largely fixed.
When your solar system reduces your grid consumption, there is less energy (measured in kWh) for these fixed costs to be spread across. As a result, your effective price per kWh increases, even though your total bill may still decrease due to lower consumption.
For example:
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Before solar, you might use 10,000 kWh per year, with $1,000 in fixed and network charges spread across that usage.
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After installing solar, you may only draw 4,000 kWh from the grid. Those same fixed costs still exist, but they’re now spread over fewer units of energy — effectively increasing your per-unit rate.
2. Retailers Adjusting for Reduced Volume
Retailers also price energy contracts based on expected consumption. Customers with higher or more consistent grid usage allow fixed costs to be averaged across more units, resulting in lower rates.
When a site installs solar, its grid demand profile changes — particularly the daytime load, which solar directly offsets. This means:
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The customer becomes less profitable per kWh for the retailer (because fixed costs are now recovered from a smaller spend).
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Retailers may therefore increase rates upon renewal to maintain cost recovery.
3. Peak vs. Off-Peak Usage
Solar primarily reduces daytime (peak) grid consumption, but may not significantly affect evening or overnight usage — when solar isn’t generating. This can cause a shift in your load profile, sometimes resulting in:
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Higher demand during non-solar hours, which may fall under higher tariff periods.
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Reduced off-peak consumption to spread fixed costs across, further impacting the balance between peak and off-peak pricing.
4. The Overall Impact
While your electricity rates may appear higher or your renewal offer may increase, this doesn’t necessarily mean you’re worse off financially. In most cases, your total grid spend decreases, but the unit rate (price per kWh) rises simply due to the smaller volume of grid energy being purchased.
In summary:
Installing solar reduces the amount of grid electricity you buy, which limits the base over which fixed and network charges can be distributed. Because those charges don’t disappear, they are recovered through higher per-unit pricing or adjusted retail offers.
The key point is that even though your tariff may increase, your total energy costs typically still decrease, reflecting the savings achieved through solar generation.