Energy Curtailment – Why Solar Batteries Are the Answer

Are you a solar household? If it seems your PV production or grid exports on your monitoring app fluctuate on a sunny day you could be experiencing an issue called 'energy curtailment’. Curtailment is by no means a new issue, but it’s an increasingly important one as more Australian households install rooftop solar panels and more renewable energy farms come online as part of the energy transition.

What’s more, even though annual output to the grid could be reduced by as much as 10% for some households¹ many may not even know it’s happening and those that do know are, understandably, not impressed. With rooftop solar one of the best means of reducing fossil fuel usage and lowering carbon emissions, could curtailment be the spanner in the works that slows Australia’s uptake of rooftop solar? 

Australia is now the global leader in rooftop solar PV penetration with more than 3.3 million households contributing to the 20GW (gigawatts) of rooftop solar power capacity nationwide across residential, commercial and industrial solar PV, with ‘grid-scale’ solar adding another 10GW bringing the total installed PV to 30GW.  What’s more, it’s expected that another 10GW of solar PV will be installed over the next 3 years.² That means energy curtailment could prove to be an ongoing issue for homes with solar, one with the potential to affect millions of Australian households – including yours.

What is energy curtailment?

Curtailment is a relatively little-known term that refers to the reduction of energy output from a renewable resource – in this case, solar energy from rooftop PV panels – that prevents it from reaching its maximum generation potential. So that’s what energy curtailment is, but what causes it? 

As demand and supply for solar energy dictate the amount of solar energy output that’s curtailed, solar energy output can be curtailed for either economic (industrial solar) or grid-capacity reasons (residential and industrial solar). Starting with the economic reasons for curtailment, solar and wind farm operators may stop exporting energy when prices go negative in the grid to avoid losing money. In terms of the grid-capacity reasons for energy curtailment, the market operator may block supply when more power is generated than the grid can handle to prevent ‘grid saturation’ which results in grid instability. It’s this issue that affects households. 

Essentially, curtailment is caused by renewable operators ceasing energy exports or by the market operator blocking supply. Yes, this is a very dry topic indeed, but it’s one that all current and future solar households need to be aware of if they’re exporting the excess energy their solar panels generate back to the grid.

How does curtailment affect households with solar panels? 

Like all developed countries, Australia’s energy grids are designed for large power stations that export energy in one direction, but now that around a third of Australia’s estimated ten million households have rooftop solar – and solar households both export and consume energy – energy curtailment levels are increasing as a result. 

As an Australian National University researcher pointed out, “Investment in transmission is definitely lagging [behind] the investment in generation,”³  but that means little to the solar households that can't export the energy their rooftop panels produce or use it at home and find that their electricity source is switched to mains electricity.

As rooftop solar exports are contributing to voltage spikes outside the accepted range and market operators are switching off rooftop solar panels to curb the risk of grid saturation, households are affected in two ways. Firstly, they get less money from the energy their panels generate and export to the grid and, secondly, they’re hit with higher energy bills due to increased dependence on grid electricity with its escalating costs.

How to resolve energy curtailment issues

While State and federal Governments have proposed a range of initiatives to address curtailment issues, even if these initiatives are implemented they offer few benefits for households – so what can solar households do?

The best solution solar households have available is to invest in a home battery storage system that enables you to store the excess energy generated by your solar panels for your own use when you need it. Grid-scale battery storage is widely recognised as having great potential to minimise grid saturation and enable more renewable energy to enter the grid by absorbing the excess power generated. Homeowners can also use home battery storage as a solution to the issue of curtailment by minimising the energy they export to the grid. 

This reduces grid reliance, stabilises electricity charges and, ultimately, kick-starts your journey to an energy-independent future in which you’ve eliminated exposure to rising energy prices. With the energy crisis showing no signs of abating and energy curtailment an issue that won’t be sufficiently addressed anytime soon, home battery storage presents a solution that Australian solar households can start benefiting from immediately. 

To check if your solar is being curtailed, check your inverter or battery app data, as this could help you spot curtailment in real-time. Additionally, as most issues that arise relate to the solar PV system, checking your energy bills regularly can help you identify potential issues with your solar, including curtailment.

Explore the sonnen product range 

Explore the sonnen home battery storage range and contact a sonnen expert to find out how a sonnenBatterie can help your household avoid curtailment issues, minimise your exposure to rising electricity prices and empower you to move towards an energy-independent future.

¹Curtailment and Network Voltage Analysis Study (CANVAS) Succinct Report 2021

²Clean Power: Nearly 1 in 3 Homes in Australia Covered in Solar Panels

³Australian renewable energy struggles to hit grid with one solar farm wasting half its yearly output