Electricity "duck" curve.

[Shannow]

http://www.vox.com/2016/2/10/10960848/solar-energy-duck-curve

To avoid being told that my story is getting old...here's a link and a story attached.

Part 2 promises fixes.

But part 1 gives a pretty decent understanding of the current trend.

 

[SteveSRT8]

haha, a great article...

 

[WANG]

Excellent. Thanks for sharing that.

 

[bullwinkle]

Wonder if any of the discussed methods of energy storage such as flywheels, or using water or compressed air to store the excess energy so it can be used later in the day could help? I wasn't aware that solar was making it's way to the grid in such huge amounts, I always thought it was tiny compared to demand?

 

[turtlevette]

That source looks to be political. Look at the teaser headlines at the end of the article. How about when you throw in wind? Makes a good argument for year around daylight savings time.

I used to watch that 5 pm peak on the SCADA system. We could flatten it by taking manual control of station transformer auto LTC (load tap changer) from SCADA.

The future of power is going to be more complex and challenging. There's no getting away from that. The up side is the both of us will have some cool opportunities.

 

[Kuato]

Interesting article. Coupled with the energy summit/podcast you posted awhile back, seems like during the day they should use the baseline power to fill the reservoirs for hydro to meet the evening demand, so they don't have to shut down the coal/nuclear plants during the day.

But probably filling the hydro reservoirs wouldn't use all of the excess?

 

[ksp7498]

I know that some solar panel providers are now recommending facing solar panels west instead of south because of this. Even though you get less total power that way, you get more power during the peak demand time (evening).

 

[OVERKILL]

Originally Posted By: ksp7498
I know that some solar panel providers are now recommending facing solar panels west instead of south because of this. Even though you get less total power that way, you get more power during the peak demand time (evening).


That's covered in the follow-up article actually

This provides a very neat suite of challenges that will vary markedly from one market to the next so I don't think there is a single silver bullet that we can coin as a "solution". Present installed capacity, the viability of these renewables in a given market....etc all are factors. Ultimately the end game is to get the fossil fuel burners out of there. In some markets, that's easy (like Ontario), in others, where the majority of their base load comes from these sources, that's an issue as alternative base load providers renewables are not so either the reliance will be on greater levels of interconnectivity (like Denmark) which brings with it substantial cost to the end user, or installing more base load capacity, which, in some parts of Europe, seems to point to more nukes going online, though that doesn't seem to be in the cards for North America

 

[IndyIan]

Originally Posted By: Kuato
Interesting article. Coupled with the energy summit/podcast you posted awhile back, seems like during the day they should use the baseline power to fill the reservoirs for hydro to meet the evening demand, so they don't have to shut down the coal/nuclear plants during the day.

But probably filling the hydro reservoirs wouldn't use all of the excess?

The problem with refilling most hydro reservoirs is finding water you can use. Most have a natural river that needs a baseflow maintained, so they are already holding back as much as they can.
Also there are efficiency loses with pumping water, and with generating power again, so overall it might make more sense for hydro dam owner just to hold back water until they can sell their power at the maximum price.
Locally we have a pretty ideal location for pumped storage hydro power at an old open pit mine. With a 700' hole and millions of tons of rock to create a lake at a top, but no one has put up the money to build it yet.
I think the real issue is if Tesla gets their powerpacks economically viable for a medium scale organization, say a hospital, suddenly their will be no shortage of storage to smooth out the peaks and valleys. Eventually there might not even be a need for large scale powergrids at all for many areas with improved solar generation and battery storage.

 

[Kiwi_ME]

It seems obvious that home solar has grown because power providers are not producing the product consumers want at a competitive price. Although the article is a bit loose about specifying whether the solar portion originates from homes or the providers themselves, it does seem to place the blame squarely on consumers with solar panels even though the providers have brought this upon themselves by not being competitive.

 

[OVERKILL]

Originally Posted By: Kiwi_ME
It seems obvious that home solar has grown because power providers are not producing the product consumers want at a competitive price. Although the article is a bit loose about specifying whether the solar portion originates from homes or the providers themselves, it does seem to place the blame squarely on consumers with solar panels even though the providers have brought this upon themselves by not being competitive.


In Ontario the reason is that home solar is massively subsidized and "bought" by the utility at a MUCH higher rate than what the consumer buys their power for. Without those subsidies and perks it would not have garnered the support it has. Ultimately the rest of the rate payers are paying for the subsidies however, in the form of the highest hydro rates in North America.

 

[Kiwi_ME]

I'm wondering why a buyback subsidy is needed on hydro power since it's already renewable?

We have no subsidies, the providers are not obligated to buy back power and those that do only pay 4 to 8 cents/kwh. Our retail rates are around 25 cents/kwh and our power is 75% renewable, the remainder coal and gas. Home PV solar is not too common here unless you're out in the boonies.

 

[Shannow]

Australia, today, as I type this the wholesale cost of power is 3.4c (Aus) per KWh, I'm paying 27c/KWh retail, and my F.I.L is recieving 60c/kWh for his rooftop solar, due to subsidies that add about 1c to my retail cost.

In my state, peak demand about 12,000MW, rooftop solar went in at 500MW/annum during the period that they were paid 18 times wholesale, and over double retail, held momentum when that was cut to 12 times wholesale and 1.5 time retail.

Last year they dropped the feed in tarrif to a mere multiple of wholesale prices after realising what was happening to grid control with that level of displacement...now consumers are complaining about being "ripped off" with the new prices...about 200MW went in last year.

It's not about competetiveness, it's about handouts.

It's still cheaper to buy electricity and run a heat pump than to use natural gas...my mother runs her reverse cycle off her solar, and feels way better about her choice.

 

[Shannow]

Originally Posted By: Kiwi_ME
I'm wondering why a buyback subsidy is needed on hydro power since it's already renewable?

We have no subsidies, the providers are not obligated to buy back power and those that do only pay 4 to 8 cents/kwh. Our retail rates are around 25 cents/kwh and our power is 75% renewable, the remainder coal and gas. Home PV solar is not too common here unless you're out in the boonies.


In Oz, the greens are swinging opinion to not count hydro as "green" or "renewable" anymore.

 

[Kuato]

Originally Posted By: IndyIan
Originally Posted By: Kuato
Interesting article. Coupled with the energy summit/podcast you posted awhile back, seems like during the day they should use the baseline power to fill the reservoirs for hydro to meet the evening demand, so they don't have to shut down the coal/nuclear plants during the day.

But probably filling the hydro reservoirs wouldn't use all of the excess?

The problem with refilling most hydro reservoirs is finding water you can use. Most have a natural river that needs a baseflow maintained, so they are already holding back as much as they can.
Also there are efficiency loses with pumping water, and with generating power again, so overall it might make more sense for hydro dam owner just to hold back water until they can sell their power at the maximum price.
Locally we have a pretty ideal location for pumped storage hydro power at an old open pit mine. With a 700' hole and millions of tons of rock to create a lake at a top, but no one has put up the money to build it yet.
I think the real issue is if Tesla gets their powerpacks economically viable for a medium scale organization, say a hospital, suddenly their will be no shortage of storage to smooth out the peaks and valleys. Eventually there might not even be a need for large scale powergrids at all for many areas with improved solar generation and battery storage.


Hydro I'm talking about is not a dammed river like the Hoover Dam or something, but rather a custom-built system using a reservoir as a battery. The same water can be used over and over again in this system, adding to it as necessary. Water flows downhill when power is needed (some in use in Australia provide power for 4 hours IIRC), then is pumped back up "recharging the battery" when there is excess electricity. The whole idea is to get the generation curve to match the demand curve.

 

[CT8]

All this and California has a time of use rate with the rate being the highest during the middle of the day. There is some disconnect between the truth and ripping the idiot consumer a new one.

 

[Kiwi_ME]

Originally Posted By: Shannow
In Oz, the greens are swinging opinion to not count hydro as "green" or "renewable" anymore.

Gee, that was depressing to learn about the methane concerns, as if it wasn't hard enough already to get off non-renewables. If that turned out to be a significant contribution it would devastate our renewable rating.

http://www.scientificamerican.com/article/methane-emissions-may-swell-from-behind-dams/
https://www.newscientist.com/article/dn7046-hydroelectric-powers-dirty-secret-revealed/

I'm a big fan of heatpumps as well. Costs half what LPG does for heating.

 

[Shannow]

Originally Posted By: Kuato
Hydro I'm talking about is not a dammed river like the Hoover Dam or something, but rather a custom-built system using a reservoir as a battery. The same water can be used over and over again in this system, adding to it as necessary. Water flows downhill when power is needed (some in use in Australia provide power for 4 hours IIRC), then is pumped back up "recharging the battery" when there is excess electricity. The whole idea is to get the generation curve to match the demand curve.


It's a small (note I didn't say tiny) part of the Australian Hydro scene.

I've been offered jobs, and also worked at some of them, and the nett flow is nearly always downhill...Tumut, the number of pumps is not the number of turbines, the nett flow is down, there is some pump storage, and they use it.

Kangaroo Valley/Bendeela there's two different sized power stations operating at different heights, with a "pond" in the middle, that provides some pump storage...yes, for some hours, but 35-50MW in a grid of 12,000MW peak demand is there, but not big.

During the drought, THAT power station was turned into a plain jane pump, to keep water flowing to Sydney, we evaporated water in the thermals to make electricity to keep Sydney drinking.

(Gil Gerard was "star" of a movie at those two hydros...Earth Force...it's a hoot).

The whole system has been privatised now, so opportunities for engineering solutions such as you offer here are restricted to price and demand...the coalers have cut their overnight minimum loads, which is resulting in less, and less cheap overnight electricity to pump storages up...hydros pull capacity to bump up peak prices.

The strategically located coastal sites that would be purely pump storage for a few hours are a great idea, but would never get approvals in the current state of Oz.

Crazy case in a neighbouring city, where certain groups lobbied hard against treated sewage returning to the river. Now a local (gold) mine wants the water, and the same people are arguing that to do so would reduce the flow in the river and damage the ecosystem

 

[OVERKILL]

Originally Posted By: Kiwi_ME
I'm wondering why a buyback subsidy is needed on hydro power since it's already renewable?

We have no subsidies, the providers are not obligated to buy back power and those that do only pay 4 to 8 cents/kwh. Our retail rates are around 25 cents/kwh and our power is 75% renewable, the remainder coal and gas. Home PV solar is not too common here unless you're out in the boonies.


Your retail rates are close to double ours, and ours are VERY high by North American standards. Our (Ontario) base load is majority nuke/hydro with wind/solar making up a much smaller percentage. We are currently running a massive hydro surplus (and have been for close to a decade) but that hasn't stopped our idiotic provincial government from allocating 100 billion to more wind capacity.

I imagine scale comes into play here a bit too. A quick search yields a total generating capacity for New Zealand at 9,603MW. Hydroelectric capacity at 5,254MW. The Robert-Bourassa dam in Quebec produces 5,616MW by itself. Our one nuke plant, Bruce, in Ontario, has a capacity of 7,276MW.

 

[turtlevette]

Originally Posted By: Shannow
[

The whole system has been privatised now, so opportunities for engineering solutions such as you offer here are restricted to price and demand...


Dot dot dot indeed.

Don't you guys get it? Not everything in the world can be done based on low cost. Subsidies have a true and valid purpose. To give a technology a JumpStart. If we all worked for bean counters, nothing interesting would ever get done again. There would be no innovation. Why take a chance on something newfangled when buggy whip and horse will do.

Edison's lighting system was crazy expensive. Why not just continue to burn kerosene? It works just fine. If it hadn't been for the government subsidizing electrification by creating the REAs, government built dams, TVA and so forth, we'd still have most of the people in the red states using oil lamps.

You need to have vision.