Every cloud has a solar lining

Solar intermittency - the interruption of solar power due to cloud cover, night-time or the sun simply not shining brightly enough - has been a major factor in preventing Australia from fully embracing solar energy. Now, the CSIRO is working hard to understand how to manage this problem.

In a year-long study funded by the Australian Solar Institute, the CSIRO - together with the Australian Energy Market Operator and the Energy Networks Association - has investigated the concerns around solar intermittency and its impact on electricity systems. ‘Solar intermittency: Australia’s clean energy challenge’ was a comprehensive study that included a review of worldwide research, collection and analysis of high-quality solar data and consultation with a range of industry experts from utilities, power system operators, large-scale renewable system operators and other industry players.

In the podcast ‘CSIROPod’, CSIRO engineer Dr Glenn Platt explained that solar intermittency is not so much of a problem now because of Australia’s fairly low solar energy usage - but, “it could be in the future, when we start to see much more solar electricity generation on the roofs of our houses or in large-scale solar farms ... And so we’re trying to figure out how much of a problem it will be and when it will be a problem so we can figure out a way to solve those issues.”

During the project, it was found that in some cases local utilities limit solar power generation because they fear that adding solar power to the grid will make it harder to manage their electricity system. Indeed, Dr Platt admitted: “... it’s certainly a significant change for them in how they’ll have to operate the electricity system. Traditionally, the electricity system’s been relatively steady, relatively easy to run; it just sits there and works. With things such as more solar electricity or wind electricity on the electricity system, power companies will have to be much more careful in how they operate the electricity system and have to be fairly proactive when they turn things on and off.”

However, the report demonstrates that the current barriers to increasing the use of large-scale solar energy in the national grid can be overcome. Dr Platt discussed some of the methods which could make this happen.

“There’s a number of solutions to dealing with intermittency. Some of them range from just being able to predict what’s going to happen to the electricity out of a solar system; so if you know it’s going to drop suddenly in a few minutes, you can do something to compensate for that.”

He noted that in this case, “We really need two types of predictions. We need fairly long-term ones, where we’re talking a few days out, how much electricity we might get out of the solar panels; and then we need very short-term ones, seconds or minutes out, how much electricity we’re going to get. We need both types of predictions to be able to run the electricity system properly.

“Other approaches to dealing with intermittency involve energy storage or batteries … In those times, you might be able to charge a battery up when there’s lots of sunlight, and then when that cloud comes over your solar panels, you can discharge the battery and avoid that sudden drop in electricity output that would have happened otherwise.”

The report was also about seeing what other people have done around the world and how that applies to Australia’s own situation.

Dr Platt said, “We found that, surprisingly, there was actually quite significant disagreement between researchers around the world on this intermittency issue, and that has led us to think, well, we really need a lot more work here to get to the bottom of this, and in particular, to get to the bottom of this in Australia.”

Dr Platt has stated that both the solar and electricity network industries are interested in seeing how this challenge will be solved, and they’re happy to help along the way.

“We’re looking to work with both electricity companies and large-scale solar power systems to try and now get some practical measurements and measure actually what’s happening in real electricity networks out there, and then try and extrapolate from that to work out what that might mean for other systems in different parts of Australia.”

Hopefully, says Dr Platt, this will lead to a bright future for Australian solar power.

“I think that solar electricity will have a very significant part to play in Australia’s electricity mix in the future, and we’ll see continued growth of solar electricity to the point where it’s really having a major, major stake in where we get our electricity from in future years.”