Solar power: What happens when we start producing more electricity than we can consume?
ABC News, 7 March 2018
While Australia leads the world in the use of rooftop solar power, some experts say there could soon be too much power coming online — and governments will have little choice but to cut subsidies.
Government figures show that last year, 3.5 million solar panels were installed on Australian rooftops last year — an average of almost 10,000 every day.
That is a 41% increase on the previous year, driven by the twin incentives of cheaper solar panels from China and rising power bills.
Now one in five households are saving money on power bills by selling excess electricity back to the grid.
Tony Wood, the energy program director at the Grattan Institute, said a big incentive for many people to adopt solar was “simply because they want to save money”.
But though the solar industry has been booming, he warned dark clouds were looming on the horizon.
“We’re getting to the point where the amount of solar power being produced in the middle of the day is so much that it can start to have an impact on the stability of the grid,” he said.
Mr Wood said there would soon be certain times of the day when there will be too much electricity to consume — so it would lose its value.
And that would become a problem for people being paid to produce it.
Mr Wood could not predict exactly when that time would come, but said it could mean an end to cheaper power for those with solar panels.
“The governments who have been happy to support solar up until now will start to say well, paying for electricity in the middle of the day when we don’t need it is actually a very inefficient thing to do, maybe we’ll stop doing that,” he said.
“Obviously people who put in solar would be very upset, quite rightly, because they were promised they’d continue to be paid.
“So you’ve got to find a way out — and possibly the only way out is the use of battery storage.”
Is demand-driven power pricing the next step?
When combined with home battery units, solar electricity collected during the day can be stored and used at early morning and evening peak times.
And Mr Wood said a shift to demand-driven power pricing could help supercharge the battery industry.
“Battery storage is one of the ways to do that.”
About 20,000 home batteries were installed in Australia last year — more than triple the number installed in 2016, but still well behind the uptake of solar.
Clean Energy Council chief executive Kane Thornton said in some parts of the country solar battery units were already paying for themselves.
“Batteries are quite a few years behind solar power and so obviously the cost of solar has come down dramatically over the last 10 years or so,” he said.
“And we’re really now just starting to see that with battery technology.
“So in coming years I think we’re going to see many many of those 1.8 million homes with rooftop solar look very carefully at battery technology, because the cost and economics just keep getting better and better.”