A picture of a solar field.

There's always the sun?

Australia has abundant solar energy resources, but until now there has been very little publicly available research on how the variable nature of sunshine affects electricity networks.

  • 14 June 2012

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Glen Paul: G’day, and welcome to CSIROpod, I’m Glen Paul. Back from study in the US and thanking NASA, NOA and the National Science Foundation for their wonderful hospitality.

When it comes to using renewable energy Australia has abundant solar energy resources and many natural advantages. However, integrating renewable energy into the national grid presents some problems. The sun doesn’t always shine and the wind doesn’t always blow.

This intermittency, as it’s called, is one of the major criticisms of solar, that something as simple as a passing cloud can drop photovoltaic generation by 60 per cent within seconds.

Until now, there’s been very little publicly available research or detailed data on how the variable nature of sunshine affects electricity networks. And research done in other countries is not entirely relevant to Australian conditions. Joining me online to discuss the latest research is CSIRO’s Dr Glenn Platt. Firstly Glenn, how big of a problem is solar power intermittency when it is part of an electricity grid?

Dr Glenn Platt: Well it’s not a particularly big problem today, but what we’re worried about is how much of a problem 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 at that point it could become a problem and so we’re trying to figure out how much of a problem will it be and when it will be a problem, so we can figure out a way to solve those issues.

Glen Paul: So what percentage of solar power input to the grid are we talking about here before we’ll start seeing these intermittency problems having real impact?

Dr Glenn Platt: Well that’s one of the really challenging questions. The short answer is we actually still don’t know. It depends very heavily on the particular situation. So in some remote electricity grids we might not be able to have a very large amount of solar electricity, whereas in some other electricity grids much closer to cities we could have a huge amount of solar electricity and one of the challenges we identified in our work is trying to figure out exactly what that number is in each scenario

Glen Paul: So the problem’s going to be when renewable’s are included into the energy mix, the output from fossil fuel power plants will need to be adjusted more frequently as power suddenly drops because of a cloud. How much strain will this place on a power company’s operation to be constantly adjusting things?

Dr Glenn Platt: Well 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 static, relatively easy to run and 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. And that sort of change is certainly a bit of a challenge for traditional electricity system operators.

Glen Paul: What about power storage then, because in an off-grid situation you’d have batteries to supply power at night or on cloudy days. What about something similar to kick in when grid power fluctuates?

Dr Glenn Platt: Sure, so 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 solar systems, so if you know it’s going to drop suddenly in a few minutes you can do something to compensate for that. Other approaches to dealing with intermittency involve energy storage or batteries, as you said. And 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.

Glen Paul: And obviously weather forecasting plays a major role here. How close to real time, such as predicting these passing clouds will be required to make intermittency less of a problem?

Dr Glenn Platt: So we really need two types of predictions. We need fairly long term ones, so we’re talking a few days out. How much electricity might we get out of the solar panels and then we need very short term ones. Seconds or minutes out as to how much electricity we’re going to get. And we need both types of predictions to be able to run the electricity system properly.

Glen Paul: And what about the report itself? I mean what is CSIRO doing in relation to addressing these issues?

Dr Glenn Platt: So the report was really just a first step in trying to look at this wherever we were considering what other people have done around the world and how that applies to Australia. We found that surprisingly there was actual 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. So, where do we go from here? 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.

Glen Paul: And how is the industry responding to this advice?

Dr Glenn Platt: The industry is quite interested. They see this as a really significant challenge. On one hand I think everyone would like to see more renewable energy in our electricity systems. On the other hand people don’t like to pay any more for their electricity and so we really need to be able to find the best way to deal with this solar intermittency. How can we cope with it without having to build lots of really expensive infrastructure and things like that? And so industries really interested and very supportive, both from the solar industry as well as the electricity network industry.

Glen Paul: And when are we likely to see power companies seriously incorporating solar into the grid, you know, beyond just roof tops and so on?

Dr Glenn Platt: I think it depends on the company but there are certainly companies in Australia looking at this very seriously right now, so Australia’s building some fairly large solar electricity systems already and there are plans to build even bigger ones and a lot of excitement from wider industry as to how big we can go.

Glen Paul: The report is designed for industry or is it suitable for anyone with an interest?

Dr Glenn Platt:It’s a fairly technical report. So it’s certainly designed for people in the solar industry or the electricity network industry but the early sections of the report and in particular the executive summary are designed for a general audience and anyone that might be interested in solar electricity. And they can get a hold of the report from the CSIRO website.

Glen Paul: No probs, so do you think it’s wishful thinking to believe solar can eventually replace conventional power generation methods altogether?

Dr Glenn Platt: I don’t think its wishful thinking that solar can replace conventional power. I think the solar electricity will have a very significant part to play in Australia’s electricity mix in the future and we’ll see just 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.

Glen Paul: Well, we look forward to that future. Thanks very much for discussing it with me today Glenn.

Dr Glenn Platt: Thank you.

Glen Paul: Dr Glen Platt. And for more information on this podcast find us online at www.csiro.au, follow us on LinkedIn and Twitter at CSIROnews, or like us on Facebook.