Facing rooftop solar panels east and west instead of north may save homeowners money and help with electricity grid stability, new research suggests.
Kirrilie Rowe, a scientist at the University of South Australia, said the electricity use of most households peaked in the morning, dipped in the the middle of the day, and peaked again in the late afternoon.
“So if we were to face our panels to catch more of the morning sun, we can better match electricity load in the morning,” she said.
“And similarly, if we face our panels to catch the late afternoon sun, we can better match our electricity use in the late afternoon.”
Ms Rowe said she was not the first person to think of pointing panels more east and west, but what she had done was quantify the benefit.
“We’ve calculated for an average-sized systemÂ you could reduce the amount of power you need to purchase byÂ between 4 to 5 per cent,” she said.
“But I think one of the critical things to note is that you’re reducing it in the peak demand periods.”
Facing panels east or west could also help stabilise the grid by generating less power during the middle of the day, she said.
The deceptively simple idea received the thumbs up from Audrey Zibelman, CEO of the Australian Energy Market Operator (AEMO).
“I think that would be fantastic,” she said.
“And that’s exactly why we alert people to these problems, because then you have very clever people say, ‘Well, here’s an easy solution’. And that’s what we’re looking to encourage.”
Around Australia, the massive uptake of rooftop solar has led to a surplus of power in middle of the day and less need for traditional power generators such as coal and gas.
“We have a whole lot of people with photovoltaics on the roof that are generating power. But they’re not using power,” said Peter Pudney, an associate professor at the University of South Australia.
“And one of the things about the grid is that you have to keep it in balance all the time. The amount of power being generated has to match the amount of power that’s being used,” he added.
Currently, traditional generators like coal and hydro are needed to keep the supply of electricity stable in a grid that was never designed to handle large amounts of rooftop solar.
Without new solutions, traditional generators won’t be able to be switched off completely without risking power outages.
There are now more than 2.3 million rooftop solar systems in Australia, according to the Clean Energy Regulator, with almost 20,000 new installations every month.
In South Australia, rooftop solar is now the state’s largest generator of electricity and records for minimum demand for grid power are regularly being set.
The AEMO has warned that within three years South Australia could become the first large electricity region in the world to effectively eliminate the need for traditional generators in the middle of some days, due to the increase in rooftop solar.
“Rooftop solar has grown so fast. And now it’s a very significant portion of the power system,” Ms Zibelman said.
“And one of the things we worry about, of course, is that when the sun is shining and there’s too much solar, and there’s excess, how do we manage that so it doesn’t create a problem for the system?”
Changing the direction panels are facing is only one of a series of solutions homeowners can take to help solve the midday solar surplus problem.
“What people need to do is use as much of their high-draw power appliances like spas, pool pumps and dishwashers, and have them running during the middle of the day,” solar installer Tracey Barnett said.
She said changes to the solar tariff in Western Australia made installing home batteries more attractive.
“The new system is now going to be paying 3 cents during the day. And then from 3 o’clock to 9 o’clock they’ll pay you 10 cents for whatever you export out,” said Ms Barnett.
“If you’ve got batteries and your batteries are full, then that will still get exported out to the grid even when the sun has set, and you’ll still be able to make some money out of the network.”
But even with changes in the way homeowners use and generate power, Audrey Zibelman says the AEMO will increasingly need more control and visibility of rooftop solar to avoid blackouts in extreme circumstances.
“Now that it’s a significant portion of the system, we want to make sure that we’re making the best use of it and have all the right kind of arrangements so that people are protected,” she said.
In South Australia, the AEMO recently mandated new solar installations be connected to the internet in an attempt to better manage the export of electricity to prevent blackouts.
Peter Pudney said the way the AEMO controlled rooftop solar would need to be designed very carefully to not impact all rooftop solar owners.
“It’s important to control the amount people are exporting to the grid without reducing their ability to generate and use their own power without exporting,” he said.