So many Australians have solar panels on their roofs that the power grid has been one step from the abyss

The Australian electricity grid operator issued a rare warning on Friday: Dangerously low energy demand. Rooftop solar energy production in the state of Victoria would reach such high levels the next day that grid managers seriously doubted their ability to keep the electrical system stable.

The figures. In Australia, one in three single-family homes has solar panels connected to the electricity grid. There are so many homes self-sufficient in solar energy that the operator predicted demand below the threshold needed to keep the system stable.

In the state of Victoria, the second richest in the country, the electricity grid is prepared for a demand of between 1,865 and 10,000 megawatts, but the usual thing is to have to cover about 5,000. For Saturday midday, electricity market operator AEMO forecast energy demand of just 1,352 MW, the lowest level in recent history.

Emergency measures. AEMO considered several emergency measures to stabilize the system, such as disconnecting solar panels from rooftops or limiting the dumping of surplus. It also considered reactivating out-of-service high-voltage lines to alleviate excess energy.

Finally, it decided to notify owners of large batteries to keep them empty, in anticipation of the oversupply of solar energy.

Context. With a joint capacity of more than 20 GWrooftop solar is already a major source of electricity in Australia. Its increasing production reduces demand for energy from the grid, especially on sunny, mild weekend days, when consumption is moderate.

To make matters worse, homes with photovoltaic panels connected to the grid discharge the electricity they do not use (the surplus) in an uncontrolled manner, further challenging the stability of the electrical grid in times of low demand.

Why is it dangerous? Electricity cannot be easily stored on a large scale, so its production must match energy consumption in real time. If demand exceeds supply, the electrical grid can be overloaded, causing blackouts, power outages, or damage to electronic devices and appliances. In addition, thermal power plants need to continue operating to stabilize the system.

Renewables complicate this process because they are intermittent, which is why we see more and more problems of oversupply: there would be no instability of the network if the network were flexible, but to achieve a flexible network dominated by renewables, more large-scale batteries are needed. that store energy at times of low demand and take advantage of it when demand is high.

A sweet sentence. Nothing serious happened in Australia thanks to the operator’s anticipation, but it is likely that the problem will get worse. It will end up requiring a reform of the electricity market or more efficient management of surplus solar energy from rooftops, as has happened in California.

The network limit is no longer reached during demand peaks in summer due to the use of air conditioners, but on sunny and mild days like Saturday. It’s a sweet condemnation: with solar energy breaking records, Australia already meets up to 70% of its energy needs using renewable sources.

Image | Solar Australia

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