The cost of solar generation

[chrisb741]

Why is the cost of solar generation positive in NSW and negative in Victoria?
Dont understand why you get paid to put power onto the grid from solar in one state and in another you have to pay to put solar power onto the grid?

[Someone]

That's averaged over the day, but it looks like there were either transmission constraints (prices tracked in all states other than NSW) or NSW had some off market pricing included.

For those who aren't familiar with the source:
https://opennem.org.au/

[chrisb741]

I still dont get why solar roof top gets negative but other forms are positive. Why dont they all suffer from the same transmission constraints?
Thought they were trying to go green, how is that supposed to happen when solar power for some crazy reason costs money to export.
If its costing money why do people bother exporting it? and how can i only import solar power so I can get paid for taking it?

[Someone]

That's averaged over the day

[chrisb741]

OK, so thats the daily average, that means its mostly negative to average out to be negative over the day, so why/how is generation negative during the an instance of the day when it costs money to generate?

[Marco]

People are lazy, system sellers had little profit motive to sell systems which could automatically curtail and the power companies are laughing.

[coppice]

Wind turbines have a problem when there is no demand for their output. They can be feathered and shut down, but I understand there are consequences for that. There are situations where its better for them to pay to keep their turbines somewhat loaded, if nobody wants the energy. There are no similar issues with solar. If nobody wants it, just just don't output it. Why would anyone pay a cent for the privilege of supplying useless solar power? Is that the whole purpose of negative solar tariffs? So that people ensure their output truly goes to zero when there is no market for it?

[Marco]

Once again, people are lazy.

Regulators should never have allowed this to happen for new systems after they ended net metering. Automatic curtailment should be mandatory (communication with inverter could be via powerline comms or if there is really no other way internet).

[coppice]

Once again, people are lazy.

Regulators should never have allowed this to happen for new systems after they ended net metering. Automatic curtailment should be mandatory (communication with inverter could be via powerline comms or if there is really no other way internet).

Automatic curtailment is now mandatory in new equipment in most places. Tariffs aren't sufficient to deal with the safety issues that islanding creates.

[Marco]

You don't need islanding for zero export, just a current sensor on the outgoing connection. Or better yet, a standardized way to communicate with the smart meter.

[Someone]

Or better yet, a standardized way to communicate with the smart meter.

... and domestic tariffs that follow wholesale market pricing.

Wind turbines have a problem when there is no demand for their output. They can be feathered and shut down, but I understand there are consequences for that.

Barely any limitations on that, only thermally controlled units cycling quickly:
https://www.rechargenews.com/wind/wind-farm-blaze-boss-blames-negative-power-prices-for-strain-on-old-turbine/2-1-1481181

If nobody wants it, just just don't output it. Why would anyone pay a cent for the privilege of supplying useless solar power? Is that the whole purpose of negative solar tariffs? So that people ensure their output truly goes to zero when there is no market for it?

There are other market forces in place, particularly that the energy delivered by solar/wind is not always being sold at the spot price (long term energy purchases) and can be "forced" into the market to produce carbon offsets/credits/"measurable commodity units that are definitely not a tax". Pretty murky stuff when you try to pick apart all the details, but the market signals are enough to push investment in energy storage.

[f4eru]

Dont understand why you get paid to put power onto the grid from solar in one state

Politics.
There's a disconnect between customer prices (often still fixed price) and market electricity prices.
Different regions and countries evolve this very differently.