A new study led by the CSIRO has questioned the validity of fears that widespread deployment of solar PV could not be supported by the electricity grid, and says Australia could support a lot more solar PV with minimum fuss.
The integration of intermittent renewable energy sources such as wind and solar has been a major issue in discussions about the deployment of clean energy, but the CSIRO study says fears about solar have been overblown, in much the same way as they were about wind energy.
Glenn Platt, the head of CSIRO’s local energy systems division, who oversaw the team that wrote the detailed report, says it was commonly thought that the maximum amount of solar PV that could be supported by the grid without significant upgrades was 20 per cent.
“That’s a very common statement, but I’m not sure we have found much evidence to support that. The analysis shows we can have a heck of a lot more than 20 per cent,” Platt told RenewEconomy.
Indeed, modeling done by the study over four scenarios showed that there was negligible impact on either strong urban or weak remote grids at 10 per cent penetration, and even at 40 per cent penetration there was hardly any impact on strong urban grids – variations in voltage at that level were minimal and would most likely go unnoticed by consumers.
There were, however, issues for consumers at penetration levels of 40 per cent in remote and relatively small grids with sparse population, where voltage swings may impact the functioning of the network. However, these issues could be addressed.
The issue about how much solar PV can be accommodated by Australia’s grids is a critical one – not just for the incumbent generators and network operators, but also for consumers and the solar PV industry itself. And it is particularly the case given the rising costs of coal-fired generation delivered through the grid network, and the declining cost of PV.
The Australian Energy Market Operator last month noted that these factors, combined with the arrival of new financing options such as zero-down leases, could spur demand for 18GW of household rooftop solar PV in the next two decades, compared to 1.6GW now. AEMO’s high-scenario forecasts suggest nearly half the households in the country with an available rooftop could be taking up solar PV, and a lot more thinking about it. A report from McKinsey & Co suggested there would be an “economic” case for 1000GW of solar PV globally within the next decade.
However, there have been concerns that the deployment of PV could be curtailed by network operators, who cite pressure on the networks for decisions to curtail development. Several towns in Western Australia, including Exmouth and Carnarvon, have imposed limits on the deployment of solar PV, even though their penetration levels had risen barely above 10 per cent. Deployment of larger scale systems has also been curtailed in parts of Queensland.
Platt says the issues were often not related to solar PV at all, but pointed to other issues. Where the deployment of solar could raise issues in weaker, rural grids, this could be managed in a variety of ways – such as demand management, short-term storage, or just planning.
“Some of the distribution networks have expressed concern, but we are yet to see any data that suggests that solar is the only problem there,” Platt says. The study did not drill down far enough to find out exactly how much more than 40 per cent can be absorbed easily into the networks, and that would largely depend on individual circumstances. More work needs to be done to find out the maximum penetration possible.
“The important message is that either way we are a heck of a long way from those levels,” Platt says. “Some particular networks have had high penetration – but this might just be a few streets. We are a long way from seeing anywhere having a real problem.”
Most of all, the study concluded that very little research had been done in the area. “Partly because stakeholders are unsure about potential network problems solar energy generation might cause, and what they will need to do to remedy them, the investment in solar has been cautious and conservative.”
Platt says the lack of detailed research was one of the most surprising conclusions of the CSIRO study. “Everyone has been predicting a boom, but no one is prepared for it.”
Similar fears have been played out about the impact of wind energy, but as is being found now in South Australia, which has had up to 31 per cent penetration in recent months, this has been largely exaggerated.
However, the key to managing it was the development of data and sophisticated forecasting devices, and while wind remains as intermittent as ever, wind forecasting systems were operating at more than 96 per cent accuracy. The grid has greater issues with fluctuating demand from customers. “People jumped to conclusions that wind was causing problems when there was not a lot of evidence to support that,” Platt says.
Solar PV is interesting because while it fluctuates less over one-hour periods than wind, it fluctuates dramatically in shorter time frames – it can drop by 60 per cent in a matter of seconds. This might cause issues when more utility-scale projects are introduced, but on a suburban deployment it could be managed with proper forecasting systems and, if necessary, with some storage. Developing more data and prediction systems are two of the key recommendations of the CSIRO report.
“If you can predict what will happen, you can predict cloud coming and output about to drop, you can do some intelligent things,” Platt says. “You might do some load drops, then got a balance of supply and demand. Or you might choose to charge up batteries.”
There is a range of options, and the geographical diversity of solar panels over large area – in suburb and single solar power station which covers several square kilometers, also means that the not all power disappears at once. “Planning can take advantage of that,” Platt says.
The important issue for Australia, the CSIRO said, was the need for a highly flexible electricity grid, and one that is designed or adapted for renewable energy sources – a conclusion that will no doubt reinforce fears that much of the current build out of $45 billion of additional grid infrastructure is ill-suited to meeting the challenges ahead, as well as imposing a massive cost on consumers.