Curtailment: the invisible problem of rooftop solar



Notice your power bills seem to fluctuate in a month? Or do you monitor your energy usage via a monitoring app and observe strange peaks and valleys in the middle of the day? You might be experiencing a problem known as 'curtailment'.


Curtailment isn't a new issue. But as more households install solar panels in Australia, it's time to shed some light on this matter.


What is curtailment?


Curtailment is a technical term for reducing output from a renewable resource from what it could have otherwise produced.


First, know that the demand and supply of solar energy dictate the amount of curtailed solar output.


There is a high supply of solar energy exported back to the grid in sunny weather. The market operator may block supply to ensure that the grid does not get overloaded, which might cause a blackout. Or, if the grid prices are too low, solar energy farms might decide to curtail their export to avoid the economic cost.



How does it affect solar households?


So why should you, the solar household owner, care? Our grids were designed mainly for large fossil fuel power stations that transmit electricity in one direction. However, solar households both consume and export power.


Household solar may contribute to voltage spikes outside of the acceptable range, especially as voltage levels are typically already high.


Authorities are beginning to control whether your system exports to the grid to curtail this excess solar energy export by households.


In Western Australia and South Australia, the market operator can remotely switch off rooftop solar panels once there is a risk of overloading the grid.


As a result, households cannot export solar energy or use it to power their appliances, so the electricity source switches to the mains.


Another way curtailment happens is when your household's solar inverter — which exports excess electricity from the home to the grid — senses a voltage spike within the local grid. It automatically switches off the home's rooftop panels.


The curtailed electricity goes nowhere, which means the average solar household loses less than 1% of its power production to curtailment. However, a study shows that some unlucky homes are losing 20%.


The amount of solar energy curtailed depends on many factors, such as the house's location. The more rural the site, the higher is the curtailment loss. Additionally, the local electricity network equipment, home wiring, the number of solar systems in the area, and the size of a solar system and inverter settings can affect the loss rates.


In a nutshell, solar households are affected in two ways:

1.You get less money from exporting electricity when the solar panels are disconnected

2.You get a spike in electricity bills when your solar panels switch off and rely on mains electricity.


Since this scenario can happen midday, even when the sun is blazing, it can be pretty frustrating as it feels like you are penalised even for using renewable energy sources.


If you want to check whether your system experiences curtailment, you'll need a smart inverter that sends energy export data to a monitoring app. Or check your power bills for any significant discrepancies.


What can you do about it?


The authorities have proposed several initiatives to improve the solar sector. Some measures include installing virtual power plants and enhancing regulation to allow dynamic and flexible export management measures. But what can the individual PV household user do?


One way is to install home energy management systems that let you time the use of appliances such as hot water tanks in the day when solar generates the most power.


Another way is to install home batteries that will let you store power for use in the home when it is needed, such as in the evening.


By installing home batteries, you keep excess solar energy for use in your own home for your household use. Your inverter will convert the extra energy to charge your solar batteries, minimising the amount of excess energy exported to the grid. In the long run, you will see your electricity charges stabilise. You also become less reliant on the grid and will not be at the mercy of possible blackouts.


Conclusion


In summary, if you took a look at your energy monitoring app or checked your electricity bill due to this article, you might have noticed the discrepancies in the electricity usage during the day. It's time to purchase a LG RESU home battery system.



If you are interested in hearing more about solar energy for your home and receiving a quote for an LG RESU or an LG RESU HOME, head on over to our quote form, and one of our certified installers will get in touch shortly.