R100,000 upgrade to say goodbye to Eskom’s tariff hikes

South African households with grid-tied solar power systems will have to spend roughly another R100,000 to upgrade their systems to be fully off-grid and avoid Eskom’s tariff hikes.

The power utility applied to the National Energy Regulator of South Africa (Nersa) for significant electricity price adjustments in 2025.

Firstly, Eskom wants tariffs to be hiked by an average of 36.15% for its direct customers and 43.55% for municipal customers as part of its regular annual price changes.

In addition to that increase, Eskom wants Nersa to approve its retail tariff plan (RTP), which would tilt the balance of fixed and variable charges in electricity tariffs more towards the former.

This means households and businesses will have to pay more merely for access to the grid.

Many households who invested in solar and backup power as a way to survive through load-shedding also use their systems to reduce grid consumption but still have the grid as backup.

We found a household that does not use any grid electricity in a month — which may include homes with solar power — could see their electricity bills increase by as much as 285% if Nersa approved both the annual hikes and RTP.

All those consuming less than 650kWh in a month from the grid will be paying over 50% more on their electricity bills.

These changes will make it far more alluring for South Africans to cut themselves off from the grid completely.

The prices of solar panels, inverters, and batteries have also plummeted over the past year and a half.

Many households with higher overall consumption now realise significant savings by supplementing their demand with solar — from the first day of operation.

For these households, the cost of a solar loan or home loan add-on with a lower interest rate and a small electricity bill is cheaper than only using the grid.

Oversizing essential to pulling the Eskom plug

MyBroadband calculated the cost of a fully off-grid solar power system that would allow a household to completely disconnect from the national grid in January 2025.

It is important to emphasise that a fully off-grid installation requires a large solar panel array and plenty of energy storage to account for long periods of inclement weather with low solar generation.

Solar power installers recommend oversizing these components’ capacities to two or even three times the capacity needed to cover 90% of regular needs with a grid-tied system.

Using Solar Advice’s online solar system configuration tool, we found a system with an oversize factor of 2.5 generally costs around R100,000 more than the grid-tied version for users with 450kWh, 600kWh, and 900kWh monthly consumption.

The inverter won’t necessarily have to be oversized like the panels and batteries, as it will only need to support the maximum draw of the house at any given moment.

A typical 60-amp single-phase grid connection can support up to 13.8kW of power draw, while an 80-amp connection will let your home pull up to 18.4kW.

Even with a high-demand geyser element, oven, and electric kettle running simultaneously, you should not be pulling over 10kW.

An energy-conscious household could get away with a 5kW inverter if they time the usage of their appliances carefully.

The table below provides a comparison of the components of a grid-tied system capable of meeting 90% of a household’s electricity demand with a fully off-grid system for a home with the same energy demand.