The Australian energy market operator is seeking emergency measures to switch off power generated through rooftop solar systems, from the electricity grid. The agency says it would be a backstop to ensure stability, as it battles with the solar output from millions of households. Some analysts claim Australia could benefit from making the solar power system more efficient.
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00:00AEMO is asking for the ability to remotely switch off or curtail some of the excess electricity
00:09from rooftop solar systems in all of the states of the national electricity market to help
00:15manage days where there's so much electricity coming from the rooftop systems that it could
00:20potentially pose a risk to the grid and imbalance the very careful supply and demand balance
00:25that AEMO must maintain.
00:27And tell us on those sunny days in particular, just how dominant is rooftop solar?
00:33Rooftop solar can contribute in some states like South Australia more than the actual
00:37demand of the state on the sunniest days.
00:40Now that's a state with extremely high rooftop solar penetration.
00:44As time goes on and households continue to install more and more rooftop in their homes,
00:50we're expecting to see similar situations in other states as well.
00:54Now it's okay if one state has more rooftop than it needs, because it can at times export
00:58that elsewhere.
00:59But if every state has more solar than they need, then of course, some power is going
01:04to need to be curtailed to keep the system secure.
01:07Now these powers already exist in South Australia, WA, Victoria, and also parts of Queensland.
01:13Can you tell us what is used or exercised before that endpoint?
01:17Yes.
01:18So before curtailing rooftop solar, the actual wholesale electricity market, where the large
01:25scale units buy and sell electricity, they're already doing what they can in order to minimize
01:31surplus power.
01:33So at times when there's too much electricity available, we tend to see very, very low wholesale
01:37prices, often negative wholesale electricity prices.
01:41And that means that today, large scale wind and solar projects are often turning themselves
01:46off before the rooftop solar systems would need to be turned off.
01:50We're also seeing the large coal units switch down as much as they can.
01:54Of course, it's very difficult to fully switch off a coal plant, because then it takes a
01:58long time to restart it.
02:00So on the sunniest days, what you tend to get is the utility wind and solar turning
02:05off, the coal running as little as possible.
02:08And if there's still too much power on the system with the rooftop, then rooftop solar
02:13would be curtailed as well.
02:15So I mean, how often is this backstop power exercised and when it is, what is the impact
02:20on consumers?
02:22It's unlikely to be exercised very often.
02:25Most days for most consumers, it won't be noticed at all.
02:28It really just is there for those handful of days that usually happen in the shoulder
02:33seasons.
02:34So spring and autumn, much like today in Victoria, where there's plenty of solar available, but
02:39relatively low demand because the temperatures tend to be a bit more mild.
02:45Consumers really won't notice this very much at all.
02:48We're only talking about probably a few hours a year in the near term that they might lose
02:53some of the solar exports.
02:55So it's certainly not something that's going to affect them every single day or materially
03:00affect the economics of installing a rooftop solar system.
03:05So does it make sense to you that national powers would be sought?
03:10It does make sense to have this capability across the entire country, because although
03:15some states have moved faster on rooftop solar, all the rest are now catching up.
03:20And there will be in the next not too distant future, a time where we have so much rooftop
03:26solar installed across the country that there is more than we could possibly need, even
03:32when the coal plants are closed down, not on every day, but on the days where you do
03:35have too much.
03:36AMR only has a few seconds within which to balance supply and demand in the system.
03:42And if they can't balance that supply and demand, then it does threaten the entire grid
03:46with blackouts.
03:47So having this as an emergency measure that can be used across any state that might have
03:52excess power is quite a sensible move.
03:56And it's worth noting that this is usually a change that affects new systems or upgraded
04:02systems.
04:03So for instance, in Victoria, where the power already exists, as of October this year, only
04:08new or upgraded rooftop solar systems must come with this capability for AEMO to manage
04:14them.