The duck curve hits Australia; rooftop solar produces too much electricity during the day, impacting stability. For some reason the grid operator describes it as a “low-demand” problem.
In an extraordinary first this week, the body that runs Australia’s biggest energy market said the supply of solar power in Victoria threatened to overwhelm demand for electricity from the grid amid mild, sunny conditions.
It said Friday’s oversupply of solar was so acute that demand for power from the grid would fall below a threshold critical for keeping the electricity system on an even keel…
In a post on social media, the company said the growing output from solar panels was forcing demand for power from the grid ever lower at certain times. These times were most acute on mild, sunny days when households and businesses were using relatively modest amounts of electricity but solar generation was at its most productive. In such circumstances, the company said, rooftop solar was posing a challenge to the stability of the grid.
…conventional plants have traditionally provided — and still provide — services critical to the safe and secure operation of the electricity grid.
Such services include inertia, or the physical property that makes it easier to balance a moving bicycle than a stationary one. Whereas conventional generators provide these services as a by-product of their design — they include huge pieces of spinning metal known as turbines — rooftop solar panels typically do not. According to AEMO, a lack of plants able to provide “essential system services” puts the security of the system at risk.
Gee, you’d think the settled scientists and all those people “doing the math” would have seen this coming. Or said something when they did see it coming. But they kept silent. Anybody who knows how these systems work would have seen this immediately before it was even installed. This situation did not present a heretofore unknown discovery.
I guess I don’t understand. If there is too much solar, you just turn off the solar. They can sit there, not producing power so long as nothing is calling for power at the receiving end. I have panels which produce power when I want, but when my emergency battery is fully charged, simply stop producing.
They mentioned rooftop solar, so I’m going to assume residential. So to answer Goofy’s question, who is going to tell home owners during these times “to keep the grid stable you must purchase our electrons and not the ones generated by the solar panels you paid for and installed?”
They are doing that to the industrial level PV plants. Maybe there are legal restraints or long-term contracts for residential systems.
I see now why they call it a low-demand problem. The conventional power plants are needed for system inertia. If there is not enough demand then the renewables are shut down, effectively increasing their overall cost of the electricity they produce. As has been pointed a number of times, the grid costs of renewables are many times higher than the direct costs.
There are already systems in place to turn down or off your residential HVAC during times of stress. Texas has used them several times this summer as critical loads approach. There are systems in place where utilities can pre-emptively raise or lower thermostats in office buildings, or turn off data centers or crypto miners, or raise and lower rates to encourage people/businesses to encourage people to use less (or more) depending on cost.
Further, the problem seems to be residential solar producing too much power and feeding it back into the grid. How about just limiting the amount of solar the household produces and not accepting “sales” back into the grid during those peak times? I don’t think they’re saying you can’t use your solar at all and must buy our power, they’re saying we’re getting too much extra solar, so we need to shut that off temporarily.
Utilities turn producers on and off all the time, that’s why there are base load, and peakers for intermediate load, and whatever the top tier is called (I forget). If they’re saying the excess solar is eliminating the need for tiers 2 & 3, and is even higher than base load that is 1) extraordinary! 2) excellent! and 3) something for regulators to figure out.
Of course it could be just a case of utilities crying “Wah, we don’t like losing control of the industry we’ve owned for 100 years” but that would be surprising given their public mindedness and easy acceptance of change and environmental concerns over the years.
Lots of examples for using batteries as “peak power”, rather than using a high cost diesel powered generator. Batteries aren’t competitive for “base power”. (natural gas, nuclear, hydro)
Are you 100% sure about that? You really think either people were blind sided or knew it was coming by kept a secret?
You might be interested in this article by David Roberts describing the “low demand” phenomenon way back in 2016. I mention that article in particular because for one it is eight years old and secondly because we discussed that exact article on this board.
I remember this, because I was quite surprised when I read it. I thought it was important, so I was going to post it here and found out somebody beat me to it. I forget who, but it made an impression on at least one other person here. Unfortunately, the search function only goes back to 2022, but you can see there have been a number of discussions of the duck curve since then. This is a relatively frequent topic, in other words.
So I’m little skeptical about your claims that this is something that was either being hidden or the experts were caught unawares. Because if a bunch of random schmoes on the Internet have been discussing it for nearly a decade it probably isn’t much of a secret.
California had this problem but it has been solved by extensive use of batteries to store excess electricity and by increasing the sharing of electricity among the regional grid operators in the Western States.
Keeping conventional turbine generator power plants operating with excess electricity available from renewables is a waste of fuel and money.
Tesla and others are making your wishes come true.
A Cleaner Grid
The future of renewable energy relies on large-scale energy storage. Megapack is a powerful battery that provides energy storage and support, helping to stabilize the grid and prevent outages. By strengthening our sustainable energy infrastructure, we can create a cleaner grid that protects our communities and the environment.
I don’t know what ‘inertia’ means in the context of electric grids. Most of the MegaPacks are being used to replace peaker plants and they save utilities lots of $$$s.
Inertia in an electrical grid is the ability to smooth out or resist changes in frequency. This is necessary to maintain stability. The kinetic energy in the large rotating masses of conventional generation sources provides that stability.
From a paper published earlier this year:
“However, the move towards RESs [renewable energy sources] is fraught with difficulties. The grid’s diminishing inertia is one of the major barriers preventing the extensive penetration of RESs.”
“There is a reduction in grid inertia in a modern grid, with renewable sources having no or less inertia replacing conventional sources of inertia, such as nuclear and thermal power plants. The reduced inertia causes an increase in the frequency deviation and rate of change of frequency (ROCOF), both of which should be within limits to avoid grid outages.”
The monitoring needs to be closer and the response times much faster when there is less inertia.
You are talking about a period before utility scale batteries were available and the grid was weak. Now batteries provide frequency control and stabilize the grid. Now the grid is more robust and not dependent of rotating turbine generators. More sharing of power across regional grids except in Texas. That is one reason of Texas building so many utility scale battery systems.
