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Solar farm has to switch off every second day due to negative prices

reneweconomy.com.au

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Re: Solar farm has to switch off every second day due to negative prices

#31

Post by donw »

JMTQp8lwXL wrote: post #22
manicdee wrote: post #18

Earlier quoted context omitted.

Executive Summary (drastically oversimplified): In a wholesale electricity market we have a market operator who estimates the demand for the near term future and opens the market up to bids for supply. Suppliers bid a certain capacity for each period, with the operator typically accepting firm supply offers, contingency supply offers, and ancillary service offers in advance. Since some suppliers are “baseload” (ie: u…

Why do they have to pay someone to take the electricity? I could take a dollar bill and rip it in half (perhaps not legally, but besides the point). I understand there's costs to shutting down a system. So, they might keep it running. But what I don't get: the electricity producer has to pay someone to take the excess electricity off their hands? The producer can't route the excess to, well... nowhere?

I'm going to hazard a guess.

If we assume the numbers for a sort of medium-size nuclear plant, we've got a total power generation of 500MW.

Dumping that kind of power is... hard.

If I haven't missed an order of magnitude, that's enough to boil an Olympic-sized swimming pool in about 25 minutes (500MW to boil 2.5ML of water, assuming STP).

So you'd either need to build and maintain the infrastructure to burn that kind of energy when it isn't needed (not cheap) or just sell the power at a loss (likely cheaper).

Re: Solar farm has to switch off every second day due to negative prices

#32

Post by movedx »

dev_dull wrote: post #9
movedx wrote: post #3

Earlier quoted context omitted.

What's more annoying is we can provide that energy for virtually free, but because it doesn't make someone else profits it gets switched off. EDIT: just to clarify: I mean I wish that solar could be socialised and made into a social commodity. We're becoming increasing dependent on electricity as time passes, almost to the point it'll be difficult to live well without it. If that ever becomes the case, I would want t…

why would they pay for someone else to use their energy? It just eats into their profits and means that their normal customers have to pay more for the solar energy.

I think the power grid should be socialised and electricity handed out for free, especially given our increasing dependency on it. Solar is technically "free" energy given there's nothing to setup and maintain except the infrastructure, versus coal/oil/gas which requires mining, refining and transportation of materials before you get to the generating and delivery parts of the process.

Re: Solar farm has to switch off every second day due to negative prices

#33

Post by GhostVII »

robjan wrote: post #19
zdragnar wrote: post #5

Earlier quoted context omitted.

Overloading the grid isn't a good idea, generally speaking

If the grid were smarter it could schedule demand for the excessive production times. It could be used, for example, in render farms or other non-time-critical high load batch operations.

Some places have flexible pricing, where electricity costs more at certain times, which allows users of electricity to do this. I don't think it should be the grids responsability to do that kind of scheduling. It would be nice if everywhere we had some kind of hourly pricing adjustment that would fluxuate within some predefined price range, then you could hook into the grids api to determine when to run your appliances.

Re: Solar farm has to switch off every second day due to negative prices

#34

Post by lightedman »

It's a PV farm, they could just take parts of the PV grid offline instead of playing arbitrage games such as paying others to take their power or trying to build storage systems (though any half-smart PV solar farm has some minor storage on-site.) It's not like the entire system is hooked to a singular large MPPT controller. They aren't bound by the typical issues of energy generation which nuclear or constant hydro-electric have.

BTW: Did you know solar panels can self-immolate if seriously defective during manufacture?

Re: Solar farm has to switch off every second day due to negative prices

#35

Post by sneak »

Aperocky wrote: post #10
rosege wrote: post #7

Earlier quoted context omitted.

Yeah I had thought surely they can find a use for free electricity rather than just turning it off

Free electricity that turns off half the time and run basically randomly for the other half? Without a battery it’s useless, and you have to pay for that battery. Treating the electric grid as a battery shouldn’t be free. It’s just in this case they found the cost of battery to be greater than the value of the electricity they’re creating.

> Free electricity that turns off half the time and run basically randomly for the other half? Without a battery it’s useless

I can't imagine that's true. Spot instances come to mind.

Re: Solar farm has to switch off every second day due to negative prices

#36

Post by rosege »

beefield wrote: post #23
rosege wrote: post #8

I'm in SA and I'm currently looking at getting solar panels and maybe a battery because we have the highest cost of electricity in the country. I'd like to know why we have the highest when the price seems to be going negative every other day?

Not knowing anything, but making an educated guess. Transmission costs?

Possibly - but NSW, QLD & TAS are well known to have "gold plated" their network and still have lower cost than here.

Re: Solar farm has to switch off every second day due to negative prices

#38

Post by duckymcduckface »

thaumasiotes wrote: post #29
steve19 wrote: post #15

Earlier quoted context omitted.

The grid has to finely balance supply and demand. You can't just dump power into the grid. If you did the grid frequency would increase out of spec and it could damage connected equipment and machinery. Water storage would only work if there is a steep mountain or big hill nearby. Another way to look at negitive pricing is the grid is paying industrial users to burn as much power as they can.

I think the dominant question here is, "I have this machinery that produces electricity, and it's hooked up to the grid. Why can't I also hook it up to the ground, and -- during periods of negative prices -- send the electricity into the ground instead of the grid?" Nobody charges you to ground your wires.

The ground is a poor load and also there's a finite amount of energy you can dump into it because every watt that goes in gets turned into heat, you'd liquify the ground very quickly at the multi MW scale.

Re: Solar farm has to switch off every second day due to negative prices

#39

Post by taneq »

JMTQp8lwXL wrote: post #22
manicdee wrote: post #18

Earlier quoted context omitted.

Executive Summary (drastically oversimplified): In a wholesale electricity market we have a market operator who estimates the demand for the near term future and opens the market up to bids for supply. Suppliers bid a certain capacity for each period, with the operator typically accepting firm supply offers, contingency supply offers, and ancillary service offers in advance. Since some suppliers are “baseload” (ie: u…

Why do they have to pay someone to take the electricity? I could take a dollar bill and rip it in half (perhaps not legally, but besides the point). I understand there's costs to shutting down a system. So, they might keep it running. But what I don't get: the electricity producer has to pay someone to take the excess electricity off their hands? The producer can't route the excess to, well... nowhere?

1. Energy can neither be created nor destroyed.

In practical terms the energy has to go somewhere. Maybe they could build massive dump resistors to burn off the energy that way but doing so would only increase load on everything (shortening component lives) for no gain.

Re: Solar farm has to switch off every second day due to negative prices

#40

Post by stOneskull »

nl wrote: post #20
rosege wrote: post #7

Earlier quoted context omitted.

Yeah I had thought surely they can find a use for free electricity rather than just turning it off

In SA there are some pump-hydro storage projects in the pipeline which should smooth out some of these variations.

Good stuff. I was wondering if maybe a desalination plant could work..
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