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Power Worth Less Than Zero Spreads as Green Energy Floods the Grid (bloomberg.com)
537 points by bumholio 12 days ago | hide | past | web | favorite | 407 comments





I don't truly understand this "problem". I understand storing the energy in batteries is currently very expensive economically and materially.

However I believe there are plenty of "goods" (irrespective of if they are bulk materials, or partially processed products) which have a high processing energy per volume ratio (this does not need to be recoverable stored energy).

Allow me to give an example: currently we have a drought in Belgium (or at least Flanders). We are not landlocked, there is plenty of water in the sea. Desalination is energy intensive. Instead of only looking at energy storage, why can't we increase the processing capacity (more desalination sites capable of working in parallel), and desalinate say sea water during the energy flood? I don't expect this to be an ideal real world example, only a pattern for identifying such examples: any product (could be composite parts, or bulk material) which is relatively compact and has some high energy per product volume processinng step. Just do the process (desalination, welding some part to another part...) when the sun shines, and store them for later.

Products with very high step energy density are good candidates for storing, and could help flatten daily variations, and perhaps even seasonal variations!

Now some companies would prefer avoiding risk if they don't have guaranteed orders far enough into the future, then perhaps there should be a market for insurance or loans, so that the company is encouraged to take the risk, instead of wasting the cheap energy...


Capital costs vs. marginal costs.

You're going to build a $100M desalination plant and run it for three hours a day? That's a ton of money sitting idle most of the day, far more than what is recovered with zero operating costs.

(This is called the utilization factor -- how long a piece of equipment is used vs. staying idle)

Ideally you want useful processes with low capital costs and expensive marginal/energy costs. Desalination is not one of those.


Desalinization isn't a good example for the reasons you say, but theptip writes below that heating water in residential and commercial settings might be better. Since water once heated stays hot for a good while in the insulated storage tank. Also buildings can be heated with hot water instead of forced air, typically through pipes in the floor. Which is nicer because it keeps your feet toasty and doesn't dry out the room so badly.

A freezer is possibly another such use case, if it keeps the temperature to within +/- X degrees of the set temperature, it can delay kicking in during periods of expensive electricity, and over-cool during periods of cheap electricity.

I could load the washer or dryer and program it to run it when it's cheapest if I'm not in a hurry.

Charging an electric car could work the same way.

Air conditioners are a huge deal, my single biggest electricity consumer. In a world where things were smarter they would chill coolant/water/ice during times of cheap electricity, and that would be used to cool during the hot evenings.

The problem is I have no way to take advantage of any of that. The electric grid isn't giving me feedback on the spot price of electricity (and in many places they don't even break it down on the bill, showing just one value for $/kwH for the entire month - that's what my bill looks like.)

Even if that problem is resolved, my appliances are too dumb to take advantage of that information to optimize my costs.

The grid needs to convey the realtime pricing information to customers, and then smarter appliances will be developed to take advantage of that information. The market may be able to do a surprisingly effective job of moderating demand itself if both the information and the means to apply it are available.


> but theptip writes below that heating water in residential and commercial settings might be better.

When I worked at Ørsted, we did this all the time. We had a huge electric kettle, which we used to produce district heating water.

But there are many more things you can do with surplus energy. You can make methane gas from pure CO2 and hydrogen when you apply electric power as a catalyst.

The methane can then be eaten by bacteria to provide protein powder to be used as supplements to feeding livestock.

Or, we can yank CO2 out of the atmosphere and store it as ethanol. I think this was discovered last year or so? Ethanol is a really good "battery", and it only discharges as much CO2 as was captured by the surplus energy used to make it, making it a clean fuel that only exhausts CO2 and sterile water.


A banal long term way of storing energy is to pump water up to some high ground. Whenever you need it, use a turbine to get the energy back.

This is exactly how the 6th largest power plant in the UK works (but the turbine is reversed to become the pump)

https://www.youtube.com/watch?v=McByJeX2evM

https://electricityproduction.uk/plant/GBR1000151/


There's a number of them all over the world. Surprisingly simple idea and amazingly powerful storage.

https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroel...


The train goes up, the train goes down: a simple new way to store energy https://www.vox.com/2016/4/28/11524958/energy-storage-rail

This sounds good to me and it claims have 86% efficiency.


considering how much trains weigh and how fast they move, perhaps the electrical trains are already being used as "linear flywheels" ?

Since kinetic energy = 1/2 m * v ^ 2 , the a slight change in velocity on the trains that are already moving fast at any point in time, could store a lot of energy (i.e. for 2 identical weight trains, from 0km/s to 1km/s is a smaller change in stored kinetic energy than from 100km/s to 101km/s ! [in fact the latter increase of 1 km/s stores 201 times as much kinetic energy than the former: ((101 * 101) - (100 * 100)) / ((1 * 1) - (0 * 0))]

Now that I think of it, this could probably explain why our local trains are suffering more and more irregular arrival times :) but why would it be kept secret or hidden in plain sight? perhaps all the negative news about negative prices for renewable energy during energy flood is just manufacturing consent to keep price hikes for the plebs palatable, or a kind of white lie to offset their airplane travels...


to be honest I'm not very impressed by the trains up/down proposal:

The trains move on a track 5.5 miles long at an inclination of 8 degrees. thats a height difference of sin(8deg) * 5.5miles * 1.609344km/mile = 1.232 km, now it may be hard to find a steep cliff 1.2km high, but you could use a smaller cliff and heavier weights, think of the steep section at the start of an amusement ride (they will probably be better equipped with safety for such systems anyway since they are used to designing crazy rides for human consumption). no need for train and electrical tracks 5.5 miles long, since the motor can reside on the top part of the cliff/hill...


Interesting, I wonder how long a rail system would need to be in order to be able to pull energy from tidal effects with the moon.

Amongst the best and ost efficient energy storage options, but very limited suitable sites.

The Balkans region, along the Adriatic coast, offers an interesting prospect: using the sea as a lower basin with mountaintop reservoirs. This is a rare topology, particularly near large populations.

What the results of localised salinisation might be is a concern though.


That requires big water deposits up in the mountains, along with a dam.

Norway is having great success with this strategy on their hydro plants.


The UK pretty much exhausted its stock of good, easy, large sites with Dinorwig.

this reminded me of underwater energy storage pilot:

https://arstechnica.com/science/2017/03/german-institute-suc...


Fascinating. When you pump the water out I wonder what it's replaced with? What holds back to pressure of the ocean at 700 meters depth? The article was very light on details, unfortunately.

My understanding is that they do not replace it with anything.

I'd assume the only thing they look at is not to go above the pressure differential that the dome/sphere can sustain.


One more example.

Bath County Pumped Storage Station in the US. Huge place.

https://www.dominionenergy.com/about-us/making-energy/renewa...


>You can make methane gas from pure CO2 and hydrogen when you apply electric power as a catalyst.

You can make methane gas from pure CO2 and hydrogen period. The reaction is exothermic, it's just the Sabatier method. You could however use electricity to split water into hydrogen and oxygen.


I was at a tour of Skærbækværket many years ago, and as I remember it, when you produce power, you need to be able to control the voltage somehow. If there is a surplus of power and you cannot turn down production, you need to dump it or the voltage will go up, destroying electrical systems. One of the simplest ways to do this is to heat water, and when you have well established district heating it's almost a no brainer what to do.

It's a nobrainer, but the electric kettles are rather expensive and are usually therefore only bought to ensure production capacity in the case that the powerplant's own kettle malfunctions.

Besides, district heating produced on power from the grid is taxed as if produced on coal, as the power has no traceability. This makes it really expensive, unless you are directly hooked up to a solar or windfarm.

That's the law in Denmark at least.

PS: I worked in the administrative building just next door to Skærbækværket! :)


> district heating produced on power from the grid is taxed as if produced on coal, as the power has no traceability.

Sounds like there is room for improvement. E.g. an agreement with an energy provider and tracking when it was used on demand as a sink for excess energy instead of base-rate heating.


Ahh, it doesn't make much sense to install it away from a powerplant. It captures waste heat and electricity, where as one elsewhere would only be able to capture excess electricity.

> We had a huge electric kettle, which we used to produce district heating water.

...and you thought you were heating with renewable energy. You were not. Much of the "surplus" power on the grid comes from coal plants (especially in Denmark!) that can't throttle down, so someone burns coal, converts the heat to electricity at an efficiency of 40% or so, and you turn it back into heat.


> ...and you thought you were heating with renewable energy.

No we didn't. As a mathematical modeller and software developer for their inhouse production optimization software, I was perfectly aware of what was happening.

> Much of the "surplus" power on the grid comes from coal plants (especially in Denmark!)

Most of the power plants owned by Ørsted are bio-converted and runs primarily on wood chips and pellets. Unless you are talking about surplus energy imported from Germany, what you say simply isn't true.

Besides, the huge amounts of surplus energy that often came from germany were caused by their massive open sea wind farms, making the energy pretty green.

Ørsed operated almost exclusively combined heat and power plants, meaning that they can produce heat and power concurrently. The utilization of energy was well above 90%, when we ran the plants this way, because we cooled the plant with the district heating water, instead of sea water. The theoretical maximum is ~98%.

We also never planned for pure power production, only to turn it into heat again. That would be monumentally stupid.

We had many, highly skilled engineers and power traders, and they absolutely knew what they were doing.


So it seems many coal burners in Denmark have switched top biomass in the past few years. I didn't know that. But someone burning wood to make electricity and someone else wasting the electricity in a resistance heater still doesn't sound like a solution, it sounds like insanity. (Not necessarily pointing fingers at you personally. Negative prices lead to insanity.)

A great example of this is ice bank refrigeration, which literally uses a giant block of ice to cool air in a building.

https://en.wikipedia.org/wiki/Ice_storage_air_conditioning


This is insightful. The solution is probably to have a spot market for electricity that is accessible via an API so that smart AC or fridge or electric car charger can make use of it.

This will encourage market for devices that can utilize the lower spot prices dynamically and keep the things more efficient overall (in steady state).


We've got these in New Zealand - once you have a "smart meter" (which I believe most homes now have), then you can pick an electricity retailer like https://www.flickelectric.co.nz that bills you according to the current price. Flick provides an API to allow you to turn on/off loads when you see fit.

Even before smart metres, NZ has had a ripple control system since the 1950s which sends signals over the electric lines to your circuit breaker so the utility could remotely turn domestic hot water heaters off during periods of high demand. The technology is pretty simple, you could reverse it to turn appliances on when power is below cost.

http://www.oriongroup.co.nz/customers/load-management-and-ho...


Yes, in my house that is implemented as a ripple control "receiver", which switches on a circuit that has its own meter. The receiver is a rather simple thing I think; basically a high pass filter connected to the mains, with the filter output driving the coil in a relay. It audibly hums when ripple is on. Every couple months, the meter reader comes by and records the total amp*hours consumed at "night rate" and "normal rate".

So, it's important to note that the old system doesn't allow one to run the heat pump both whenever it's wanted, and also on the lower price ripple-controlled power. Similarly in the other direction, it doesn't make sense to use ripple control to decide when to feed back in to the grid if you have generating capacity from PV or whatever.


Do they have individual control per outlet? Those loads namely ask quite a bit of power. The last mile with respect to control in the sense of a smart switch or plug per device is the most expensive part till now. That, assuming you can for internet access use the smart meter connection or the consumer's WiFi.

It seems people reuse the API which is used by the app. An example: https://www.npmjs.com/package/flick-electric-api

So it provides pricing info, not any home automation.


that's brilliant

Some electricity utilities offer this as a sort of service to their customers, where they detect high grid utilization days and notify customers they can save $ by reducing consumption on those days. Here's PG&E's page about their version: https://www.pge.com/en_US/residential/rate-plans/rate-plan-o...

It's not "smart" or automated, but it's a baby step.


This concept is called Demand Response and is quite prevalent. Consumers receive a discount for reducing their load at peak times.

This frequently targets very high demand customers rather than residential for the simple fact that it's easier to ask a company to delay starting a single piece of machinery than to reduce the load on an equivalent but large number consumer appliances like refirgerators.

Doing this at a residential level will require significant costs to support at a residential scale. Technology is the key in solving this problem.


I've been signed up with PECO for years in Pennsylvania for their SmartSaver program that targets my residential AC during the hottest summer months. I get a bill credit every month for participating.

https://www.peco.com/WaysToSave/ForYourHome/Pages/SmartACSav...


Instead of API, they could encode relative price directly into the power source.

It’s not an encoded price but some smart grid connected devices do use the frequency as an indicator of the grid has lots of demand (slightly lower frequency, generally higher price) or lots of supply (higher frequency, generally lower price).

Rainforest Automation sells a little Linux appliance that reads smart meter data from your energy meter. Some providers, (including mine - ComEd) provide the spot price via that meter. The Rainforest device has an api both cloud & local.

Whenever I get a couple of bored minutes I go and update a little go library I have to work with it https://github.com/kklipsch/reagle


Easier solution: The net frequency is already used for load control. Require consumer devices to react to it by law. No internet or setup needed

There is a program to provide that feedback. I already own an enabled water heater for example.

https://smartgrid.ieee.org/ http://www.whatissmartgrid.org/smart-grid-101


This is the only valid reason I have heard for having smart household appliances.

You made me laugh, but yeah I can't think of another good reason for my refrigerator to be "smart".

Heating a big, isolated water tank was pretty common when I was working in the industry 25 years ago. Power was much cheaper during night so you used that to heat the water tank and daytime you used that water to heat the building. Lately this has been available to private customers also, price by the hour. (Sweden)

Check out https://mixergy.co.uk which recently came out with a nice solution.

Yep and yesterday FullyCharged released a vid about it being on trials - https://www.youtube.com/watch?v=z1Z4JCoPAGc

An interesting note from the video is how they said they could detect the grid frequency from the plug to detect times of over supply and (in theory) that would be the right time to absorb some of that excess.

Some other interesting benefits (mentioned in the comments) about how it can periodically cycle the heat better than traditional water tanks to kill off bacteria.


That's where I got it from. Was likewise intrigued by the frequency remark, interesting stuff.

Storage heaters are common in many parts of Europe: https://en.wikipedia.org/wiki/Storage_heater

They already work on this principle, more or less: heat up overnight when electricity is metered cheaper, then discharge during the day.

There are several companies working on making "smarter" versions that can switch on and off in response to real time data.


> The problem is I have no way to take advantage of any of that.

Some metropolitan areas have residential level demand response programs that address the obverse issue: when there is too little power, participating opt-in residential electricity customers with a qualifying Internet-connected thermostat would see their HVAC systems reduce power consumption through adjustment of the temperature set point. I suspect most of them use OpenADR [1].

If my skim of the OpenADR specification (requires free registration) is off, and we can't use it to pass pricing signals through the EIEvent/Quote/Report/Avail/Opt services, then we can use the OASIS Energy Interoperation parent specification, though that seems much more heavyweight and baroque to work with, and likely a harder sell to utility organizations to adopt. The utilities would need to expose pricing history as well, so longer-term planning by consumers can be performed through predictive trend analysis.

The communications and protocol infrastructure is there to convey the information to your residence, but the back-end at the utility side is an open question, and likeliest hardest to hook up. If I had access to near-zero cost electricity when they're trying shed load, then I would use it for drying clothes, chilling a pool (thermal mass) during hot months, heating a pool (thermal mass) during cold months, baking and pressure cooking while running a kitchen A/C at full blast, etc. All of these activities either use capital equipment already paid for, or very cheap to acquire to add to my existing equipment stock (like heat exchanger to thermal mass and even a brine tank).

[1] https://openadr.memberclicks.net/


I wonder if a less efficient desalination plant would be cheaper. The modern efficient plants use RO with pressure exchangers, I think. Maybe a flash distillation plant or an RO plant without pressure exchangers would be economical to operate intermittently.

But desalination may be a poor example in general. It’s not actually very energy intensive, at least compared to the value of potable water in an urban location.


Yeah, if I was gonna build a desalination plant built to use <$0 cost electricity, I would essentially build a giant (distillation) still. I'm not a process expert in flash desalination, but it looks similar to (maybe identical to) a still.

Just a big resistor in a big tank (or pond), a big fume hood and coil to another tank. Capital cost can probably be minimized a whole lot.


Seeing as "boiling the ocean" is the standard business phrase used to dismiss an overly ambitious and likely impossible to execute plan [1], there would be something beautifully ironic about a startup whose explicit goal is to solve a real world problem by literally boiling the ocean.

[1] http://workingwithmckinsey.blogspot.com/2013/11/Avoid-Boilin...


You can use sun light directly for that. Just paint your boiler black, maybe concentrate some sunlight with cheap mirrors.

This works well when you have a lot of sun. Instead you might have a lot of wind.

Also, you only want to run the desalination plant when the electricity price is too low ("below zero" with the transmission included), so you want generators for most of the time, when you actually sell the power.


Yea but not at night.

The entire point of this discussion is to figure out how to use electricity only during the day.

Even for RO the big expenses are running the pumps and fouling of the membrane, caused by high concentration of salt due to the high pressure used. If you weren't worried about throughput they last a very long time. You could use cheap electricity to pump water to a reservoir and use gravity as the pump for cheap RO. It isn't any different from any other source of off grid storage.

What about using the energy for various forms of carbon sequestration? Making biochar [1] for example? An area's biodegradable waste could be collected according to existing garbage schedules, and the grid's excess electricity used to create biochar from it at garbage/recycling sites.

[1] https://en.wikipedia.org/wiki/Biochar#Production


A desal plant is a useful thing and can be run around the clock off traditional energy sources. The "free energy" hours would help lower the costs.

I can even imagine a SETI-like application where people who over-generate power are able to donate it to causes of their preference...


But if you are using traditional energy sources to run it all the time, it is no longer 'solving' the problem of burning off excess energy during peak renewable times.

Someone is having to build a lot of highly wasteful, redundant infrastructure.


Rational cryptocurrency mining firms can use the excess (unstorable) energy by converting it back to money (while the sun shines and the wind blows).

Money > Energy > Money

> Someone is having to build a lot of highly wasteful, redundant infrastructure.

We're nowhere near having the energy infrastructure necessary to support everyone having an electric vehicle yet.

Energy storage is key to maximizing returns from renewables and minimizing irreversible environmental damage.


Not hours per day. But if your climate has wet winters and dry summers you might choose to build a desalination plant that you only really need to run for three months per year.

And then you have the plant sitting there for most of the year, able to help the power grid. So the example makes sense.


For something like a desalination plant, I wonder if that would be a good candidate for pumping water up a hill/tower/something, and then using the stored energy the other 21 hours per day.

I can't imagine that the capital required for "water boiling equipment" would be very high. Metal tanks, pumps, heating unit, etc.

Yes, but you are in one sense "competing" with other solutions (such as batteries) that face the same utilization factor problem.

Yes, depending on the timescale considered, the utilization factor of the plant should be weighed against the utilization factor of flood energy. In the long run it should pay itself back.

> In the long run it should pay itself back.

So in financial terms wouldn't this mean a rather weak profit margin? Plus the relatively high-risk that flood energy might not always result in free or negative energy prices gives it a bleak risk-to-profit ratio.

In other words, there would always be something more utilizable to be done with excess energy (e.g. mining bitcoins etc. and buy water with it when you need it).

PS: But I like the main point you make, to take in more aspects when calculating efficient renewable energy systems. Not a crypto-investor (or even believer).


Right, I explicitly mentioned not really believing desalination to be a good example, I was using it more as a fake illustrative example.

In hindsight I should have ended with posing the following question: how do we make a simple guide for factory/etc operators/consultants to recognize such steps in their production line?

Desalination is a bad example, because you need a complete new plant, while it is conceivable that other products have one or more energy dense steps.

What should such instructions look like?

Follow the product through your production line, and at each step measure the energy consumed per part at the step, and the volume per part when efficiently stacked. Also note if the step is automated or needs a human, if it is human, check if it can be automated.

If it is automatable, and the energy density for the step is high enough, calculate the cost for changing the production line, allocating sufficient storage, and possibly automating a certain task, and parallellizing the step such that it can be run during energy flood. Then calculate through the price difference how fast it pays itself back.

Mention the importance of actually measuring the energy consumption, instead of just reading off a machine specification of wattage, and cycle time.

Etc.

Edit:

The banks that wish to invest in cheapening such a step could train consultants and send them to factories interested in good deals. I.e. any potential profit is shared between company and bank, and the bank takes the risk (hence has the motivation to do the calculation properly, and will have best knowledge through experience of suitable step energy densities)


I think the core of your idea would work well in theory; a much simpler example would be heating water, which both residential and commercial buildings do quite a lot. Once you have hot water, you can keep hold of it for quite a long time in a properly insulated tank.

Or at a higher level of abstraction, instead of us trying to figure out which "energy dense step" is the right one to target, instead the grid can provide a real-time price signal that flexible loads can use to get a cheaper overall rate by selectively turning on when the demand is lower.

This stuff is pretty well discussed under the umbrella of "smart grid" technologies: https://en.wikipedia.org/wiki/Smart_grid#Market-enabling


In the oil market, stabilization of price occurs only because a handful of countries (really just Saudi Arabia) maintain extra capacity. They don't run their capital assets at 100%. This is where capitalism fails. You need one absolute authority, some autocrat who doesn't care that their processing plant isn't running at 100%, who is able to react instantly without making new capital improvements. This is the place for a state-owned market participant, either on the supply or consumption side.

This idea may be outdated. USA has been considerably undermining Saudi's traditional role of swing producer. Not through their centralised market control, but by having many intensely capitalistic shale operations, each with profitable capacity at a different price-point. Each one quickly toggles on/off when the market price crosses its own threshold.


just because there is fluctuation, doesn't mean there's nothing stabilizing it.

OPEC without a doubt decides output and price (with noise). They can hold the economy hostage nearly unilaterally and have for decades - see the 70s supply shock.

Interesting thought. In Richard Rhodes new book Energy, he describes how an early iron smelting works in England, faced with temporarily low demand due to a recession, rolled its excess iron into railroad tracks which could be re-used for other purposes once demand recovered:

  Richard Reynolds, who managed the Darbys’ Ketley
  ironworks, near Coalbrookdale, in the 1760s, introduced
  cast-iron plates and then cast-iron rails to protect the
  wooden rails from wear and tear or to replace them. He
  had another reason as well for using iron: as an
  ingenious storage system. A depression following the end
  of the Seven Years’ War in 1764 reduced demand for iron
  products. Prices fell. Reynolds wanted to keep his
  furnaces going and his employees at work. Rather than
  warehouse the excess production, Reynolds used it for
  rails. Then, if iron prices went back up, he could have
  the rails removed and sold. Reynolds “tried it at first
  with great caution,” his granddaughter recalled, “but
  found it to answer so well, that very soon all their
  railways were made with iron.”

For mobile users:

Richard Reynolds, who managed the Darbys’ Ketley ironworks, near Coalbrookdale, in the 1760s, introduced cast-iron plates and then cast-iron rails to protect the wooden rails from wear and tear or to replace them. He had another reason as well for using iron: as an ingenious storage system. A depression following the end of the Seven Years’ War in 1764 reduced demand for iron products. Prices fell. Reynolds wanted to keep his furnaces going and his employees at work. Rather than warehouse the excess production, Reynolds used it for rails. Then, if iron prices went back up, he could have the rails removed and sold. Reynolds “tried it at first with great caution,” his granddaughter recalled, “but found it to answer so well, that very soon all their railways were made with iron.”


Thank you.

Huh! I had no idea that timber railways were ever a thing to be replaced with iron in the first place! Neat!

Note the "Reynolds wanted to keep [...] his employees at work" part. This was at a time where being an employer was understood to come with a responsibility towards the people you employed. Well, at least today people have 40 hour work weeks with the weekends off.

Hard to know for sure, but it might well have been more self-serving than that: good employees might have been hard to come by, and hard to re-acquire/retrain once lost, so maybe he just wanted to keep them around and occupied so that they'd still be available once demand rose again.

It's likely a short-term problem. There are plenty of ways to fix it (besides the one you mention, just shut down coal & oil power plants for good and replace them with technologies like natural gas or hydro that can easily react to spikes in demand), but all of the fixes require capital investments and time to build factories & tooling.

Basically this is a problem because a bunch of existing incumbents are probably going to go bankrupt, or at least have to write down a lot of capital equipment and invest in new technologies. Boo-hoo for the incumbents, but it's good for consumers and good for society.


> Basically this is a problem because a bunch of existing incumbents are probably going to go bankrupt, or at least have to write down a lot of capital equipment and invest in new technologies.

That's not how it works. In Germany, the government subsidizes farmers to put up Windfarms, then forces the electric companies to buy the electricity at an inflated price, which those companies charge their customers for. As a result, energy prices in Germany are almost doubled for citizens, whereas companies get to have exemptions, of course.

Then they need to sell surplus energy for negative money when production is too high and import (often nuclear) energy from neighboring countries when it's too low. While they did get rid of most (domestic) nuclear energy, essentially the same amount of fossil fuel is still required to maintain the baseline.

It's utter nonsense, but the Germans get to pat themselves on the back for being so green. Well, except for all that coal energy that also needs subsidies because of those poor coal workers...


The coal terrorists are able to demand subsidies not because of their poor workers (they are in fact laying off lots and lots of workers as a side effect of mergers, and their total employment is just several thousand people) but because a lot of local government is funded by coal company shares held by cities. This is why coal is still a thing.

>"a lot of local government is funded by coal company shares held by cities."

Do you have a citation for this? What are examples of the many local governments that are funded by coal company shares? How do you fund a local government by buying shares in a coal company?

Coal is "still a thing" because it is incredibly abundant and despite being horrible for the environment, burning it is a thermally efficient means of creating steam to turn a turbine.


Over here, in Germany, specifically NRW, it's quite literally true - a bunch of local councils hold a lot of RWE (local coal company) shares and fund local services from dividents. They were very upset a couple years back when RWE decided not to pay out dividents. Here's a news article from back then (in German) https://www.welt.de/wirtschaft/energie/article152907251/Waru...

Oh interesting, were these stocks originally purchased with tax payer money then?

You hit at an important dimension which is that the problem is not technical per se, it's really a problem of market design. Wind power purchase agreements should allow curtailment (since it is very easy to ramp a wind farm /down/) when needed for system reliability. However, this reduces the rate of return for wind farms so politicians that are looking to maximize wind build-outs will not favour this.

It's also beneficial to increase the size of the power market geographically, which reduces the variability of wind generation, rather than arbitrarily stopping at national borders.


We already have a mostly-unified central European power market. IIRC the whole central Europe grid is in a single market. Also note that providers with international transport capacity can use that to arbitrage over them.

I think, it's only in theory like this, since you can't route energy over large distances without significant loss.

You do not want to force curtailment of clean energy. You either force curtailment of fossil generators (and let those operators deal with the operational complexity of doing so) or incentivize storage.

In the real-time operating window, some generators may have must-run characteristics. For instance, hydro with downstream flow requirements for fish habitat or agricultural use or nuclear without thermal bypass. It's easy to say 'let the operators deal with the operational complexity', but if you're going to need to that nuclear unit in 6 hours you can't tell them to pound sand and poison their reactor now. Furthermore, even if the energy from some conventional generators may not be needed, they may be required to run to provide grid ancillary services such as operating reserve (the ability to ramp up or down rapidly) or to avoid violating system operating limits due to physical constraints on the transmission system.

Since wind turbine generators will not experience or cause physical damage due to rapid curtailment, only commercial harm, in a scenario where the spot price is going to zero or negative (i.e. the marginal energy being produced is not valued by anyone), it can make operational sense to curtail them before higher emitting generators under certain conditions.

Keep in mind I'm speaking only to the real-time operating considerations (think a time horizon of 24 hours) not the larger generation planning perspective. The system should be planned in a way that minimizes the need for renewable curtailment, but that's a long-term goal that isn't accomplished yet. Operating on a strict zero-curtailment basis for wind turbine generators reduces system flexibility and maneuverability and results in costs for all ratepayers.


It's not utter nonsense because it provides a much more stable market for companies building renewable energy plants and allows them to finance research and development. A lot of the improvements in solar energy technology were financed thanks to this scheme.

Same in Ontario, Canada. They heavily subsidized green energy sources and then laid the debt on the publicly owned power utility which passed on the cost to ratepayers, leading to the highest power rates in North America and a utility that is still heavily dependent on legacy nuclear and hydro to provide grid stability.

Boston (also in North America) paid 21.9 cents/kWh in June. As I type this, Ontario residents are paying on-peak 13.2 cents/kWh.

https://www.oeb.ca/rates-and-your-bill/electricity-rates

https://www.bls.gov/regions/new-england/news-release/average...


RWE would like to shut down a few coal power plants that are no longer profitable in the current distorted market. But the government, the very same technically illiterate government that fouled up the market in the first place, declared that to be illegal, because the plants are "relevant for grid stability".

> Boo-hoo for the incumbents, but it's good for consumers and good for society.

Right, the most expensive electricity anywhere in the world, except for Diesel powered islands, is good for customers.


Is the responsiveness of an oil plant so different from a natural gas plant? Why? They're both essentially a furnace fueled by a flow of combustible fluid, right?

NG plants tend to use gas turbines, which can ramp very quickly indeed. Steam plants are a lot slower (thermal stresses and whatnot).

Very little electricity is produced with oil, BTW. Steam plants are usually coal or nuclear.


Note: many bigger gas plants are combined cycle, the exhaust of the gas turbine generates steam in a waste heat boiler for a steam turbine. Often multiple GTs on a single ST.

Natgas is a turbine engine directly; coal and oil uses a boiler running a steam turbine.

They are similar, but outside of small islands few people use oil for power generation due to the high cost compared to natural gas.

I think Pumped Hydroelectric Storage is what you are looking for. I've seen a few of them here in Switzerland. I think many were originally built out with the train system's grid for it's reliably scheduled low and high capacity times.

http://energystorage.org/energy-storage/technologies/pumped-...



Does Belgium (OPs example) have the geography necessary to support pumped hydro? Your example, Switzerland, is significantly more mountainous than Belgium.

Wallonia has at least one pumped hydro that I know of.

There were plants for a 'energy island' 300MW hydro plant at sea, near the large-scale wind farms. The idea is the same, pump sea water up an artificial horse-shoe shaped island. A nice bonus is that you can play with the tides as well. The height difference does not have to be great, if you can compensate with a large surface area.

As far as I know, those plans were shelved. A quick googling says that similar concepts are being considered for interconnected dutch/danish wind farms.


https://en.wikipedia.org/wiki/Coo-Trois-Ponts_Hydroelectric_...

It has 1164MW capacity, with ~1000GWh/year supplied.


I know of at least one pumped storage dam in Belgium, in the mountainous southern part (Wallonia)

There is a video in German on youtube where Prof. Hans Werner Sinn explains, why Germany can't store the excessive amounts of renewable energy in Pumped Hydroelectric Storage. You would need too much storage capacity, especially since you need two basins and the geological features necessary aren't there. He even calculated how this would work in a compound with Norway.

https://www.youtube.com/watch?v=rV_0uHP3BDY

I really doubt Germany's "Energiewende" is really possible, since solar doesn't generate energy at night and wind energy has really large spikes. This is not the energy you want to have in a large grid and storage isn't possible at such volume. I even calculated how many Tesla walls a city like Munich would need to have a week worth of energy stored and I really, really doubt, this is physically possible or economically viable.

Germany's "Energiewende" is something politicians would like to have, but the problems and cost this is causing (google "site:heise.de tennet") aren't shared fair.


This is somewhat misleading - there is a Europe-wide energy grid, Germany has many neighbors, and a lot of power has been flowing across borders even before this project started. It doesn't make sense to look at Germany in isolation. While I agree that the German approach is misguided (should have shut down coal first, not nuclear) I don't think it's as problematic as you make it seem - the spikes in wind average out excellently when you look on the scale of several countries, and daytime demand for solar power is large and growing due to industrial use (residential use peaks in the evenings, but residential use is insignificant compared to industry). A significant component of the Energiewende is replacing baseload fossils (coal) with peaker gas plants but the coal industry is very powerful and very much opposed to this, and many local governments are in coal industry pockets and resist any coal reduction (this is one reason why nuclear was shut down first). Peaker gas plants operate only when the demand is high and supply is low, running on a much lower duty cycle than a baseload plant. The way things are going now, there's been a rapid nuclear phaseout and there's a glacial coal phaseout very slowly happening, but solar and wind installations have been growing and are displacing more and more baseload. Eventually this will price baseload coal power out of the market, and then we'll see if the coal terrorists are powerful enough to get a bailout or to get solar legally destroyed like they did in Spain.

Peaker gas plants running on gas imported from whom, Russia? At least Germany has the biggest gas sorage capacity in Europe.

https://www.ecfr.eu/article/commentary_europes_vulnerability...

A possibly better strategy would be to produce DME using excess capacity and convert diesel vehicle engines to DME. Then export both the cars, the fuel and the tech to produce the fuel locally. Maybe even use it as input for peaker gas plants and shipping fuel. Germany has all the resources necessary to establish and lead such a market. Plus they don't need to throw away decades of investment into diesel ICE R&D. See chapter 2.2 of this article.

http://www.oil-gasportal.com/dimethyl-ether-dme-production-2

http://www.iea-amf.org/content/fuel_information/dme


Germany already uses large amounts of gas, mainly for heating, hot water, and cooking. It's not like using coal for electricity changes the fact that Germany depends on gas imports.

A few alternative storage mechanisms:

- Splitting water into the fuels for fuel cells

- Converting in-ground swimming pool to neighborhood-scale battery


Is there a way to implement gravity batteries on a household-level scale? Shouldn't we all be using solar to lift a weight during the day that will lower during the night to feed the grid?

I believe aluminum is nicknamed "solid electricity" due to the ore purification process or somesuch; which dovetails well with the strategy you outline here!

Unfortunately it doesn't. Aluminum needs a lot of electricity, but it needs to be consistent for several hours. It takes a lot of energy true, but the furnaces need to be at operating temperature. You can't just turn them on and off, there are startup and cool down times that need to be accounted for.

> Aluminum needs a lot of electricity, but it needs to be consistent for several hours.

Then Aluminium smelting is an excellent match for wind and solar. Quoting https://hal-mines-paristech.archives-ouvertes.fr/hal-0052998...

"Typical numbers in accuracy are an RMSE of about 10- 15% of the installed wind power capacity for a 36 hour horizon."


If I understand right, that figure is measuring the accuracy of a prediction of electricity production, not the constancy of the production. We can't smelt aluminium with no power even if we have predicted that there'll be no power.

To be honest I don't know, but I do know taking advantage unpredictable power of this sort is why Aluminium plants are built in the first place. Where I live they are paired with coal fired plants. The reason they are paired with coal fired plants is coal can't change it's output fast enough to match the somewhat unpredictable changes in electricity usage.

So the coal plant needs someone who will buy power when it's cheap, and not use (much) when its expensive. Apparently an Aluminium smelter fits the bill nicely. I presume it uses enormous of amounts of power to disassociate the Al(OH)3 but needs only a small amount of power to keep the pots at operating temperature which is not particularly surprising as the pots can be thermally insulated.

Maybe the above claim that Aluminium can't tolerate rapid changes in available electricity is true, but it sounds odd. Coal fired plants often "trip out" - meaning the generator drops off line without warning. This is an unpredictable change that happens much faster than the sort of unreliability we see from renewables - it's a huge change that happens in milliseconds. And it's not uncommon: https://leadingedgeenergy.com.au/coal-fired-generators-trip/ Again, the Aluminium plants seem to cope with this extreme unreliability just fine.


You might be able to add a separate process where salt gets melted, stored, and used to heat furnaces.

Current furnaces do. But what if you changed the manufacturing process as well so that maybe the yield isn't as high but it's essentially "for free" in terms of electricity?

What you’re proposing is synonymous with “let’s make unobtainium with our spare electricity!”

If we could make anodes which weren’t destroyed by falling to a low temperature, we’d already be doing it.


About ten years ago I read a paper describing a pilot plant in 1950's Norway that was electrowinning iron from sulfide ore. I think the energy usage was 4-5kwh/kg.

Roughly the reason it's not economic is electricity nominally costs about 5 times what coal/nat gas does. And with the current carbon footprint of the grid it probably doesn't reduce CO2 emissions.

But that could change with as clean grid that has wild daily price swings. Electrowinning iron and other metals could easily soak up excess power.


There are some aluminum plants in Germany that do this[1]

More ambitiously ARPA-E has a program where one of the goals is light metal production(aluminum, magnesium,etc) using variable energy sources[1]. One of the interesting possibilities they present in the program is being able to use molten metal produced in refining as an energy storage medium. Although I couldn't find any program participants doing this one is using thermal energy storage for metal production[2]. A fair amount of metal refining processes need high amounts of heat and heat can be stored easier than electricity at scale.

[0]https://www.greentechmedia.com/articles/read/german-firm-tur... [1]https://arpa-e.energy.gov/sites/default/files/documents/file... [2]https://arpa-e.energy.gov/?q=slick-sheet-project/high-temper...


Haha, I like that description a lot. You can even make small batteries out of little more than aluminum, an electrolyte like salt, and (I think) a way to bring oxygen to the cathode like activated charcol:

https://en.wikipedia.org/wiki/Aluminium%E2%80%93air_battery


Another idea along the same vein is temperature control. Say the comfortable range is 20 to 25 degrees. Normally air conditioning in the summer cools to 25, once electricity becomes free it could turn on and start cooling towards 20, storing that power in the form of cool air. In the winter, buildings with electric heating could do the opposite towards 25.

These systems spin up quickly (at least in residential homes) and are a substantial fraction of our energy use.


You "currently" have a drought, but otherwise you have plenty of water, so a desalination plant isn't a wise investment (yet).

Also keep in mind that these are energy spikes that cause negative prices, whereas most industrial uses need a constant and even supply. These spikes are countered by periods of little to no energy.

This is the biggest problem with (most) renewables, they cannot entirely replace coal or nuclear energy for that reason. Energy storage (at cost) is an unsolved problem.


> Energy storage (at cost) is an unsolved problem.

Super-true. It's actually pretty fascinating how it's currently done in the grid; storage of energy is often done by converting it (at significant efficiency loss) to a mechanical format.

Those formats can get very creative---traditional is "pump a bunch of water uphill into an artificial reservoir," but in areas where big dry mines are available, capping the mine and pressurizing the air inside is also used, which feels super-weird but apparently works?



I've never heard of this before and it sounds really cool. CAES on Wikipedia: https://en.m.wikipedia.org/wiki/Compressed_air_energy_storag... UK project: https://www.storelectric.com/technology/

Take for example UKs wind energy input, which is charted here: http://www.gridwatch.templar.co.uk/ (might need to zoom in a bit)

The periods of "little to no energy" take up less time than periods of "more than little". Such periods are not as your phrase suggested, the norm broken up by occasional spikes.

Total energy supply and demand is never constant or even, it varies throughout days, weeks and seasons. That variation has always had to be accommodated.

Even without more storage (hydro, battery, future??) the grid can use almost all of the input which renewables can throw at it, and use existing plants to fill in gaps.

But there will be more storage, and long range transmission lines, better solar panels, batteries and windturbines. There is no major unsolved problem here, like nuclear fusion or Mars habitation has, its just a matter of mobilizing with existing technology. A matter which has been politically delayed for too long...


Overbuilding renewable capacity can significantly reduce the needed storage capacity, so the issue will probably get more pronounced rather than better with time.

They will slowly eat away at base loads and lower costs.

In the meantime, you address marginal demand at a lower cost.


If you wait for power prices to be negative (or merely lower than usual) you are not getting an economic return on the money you put into the desalination plant when it is not running. Think about it, if you get a 100M Euros loan to make a desalination plant, how long will it take to pay that off if you only run your plant a few hours per day vs 24 hours per day. Whether it makes economic sense depends on the difference in power prices, the capacity factor, and the ratio to capital cost.

Germany has been attempting to make it work by turning the surplus electricity into hydrogen gas (and then maybe to something else, methane, diesel, ammonia, etc) by splitting water.


http://www.abc.net.au/news/2018-08-08/hydrogen-fuel-breakthr...

Ammonia would be preferrable as it is carbon-free and readily liquified.


There's plenty of demand for hydrogen as hydrogen. And one of the things the Germans are doing is mixing hydrogen into the natural gas supply. That's pretty cheap to do compared to having to spend energy on chemical alchemy to turn the hydrogen into something else. Another option is to turn it into natural gas, plenty of existing infrastructure for handling that as well. So, ammonia is interesting but by no means a slam dunk.

And whether it makes sense to ship it internationally is an open question given the differing economics of green hydrogen vs sticking a hole in the ground and having fossil fuels come out. Here's what I said in the other thread:

"The comparative advantage nations have over each other in energy in a post-fossil fuel world will be much reduced. That is, Saudi Arabia has a huge advantage over Japan in terms of cheap fossil fuel energy, so Japan imports a lot from them. Though Saudi Arabia likely has an advantage over Japan in renewable resources, its not as dramatic as their fossil fuel advantage, so Japan would invest in their own energy resources and import less of them.

Because of this there will likely be much less international energy traded in general."


Was about to mention that too. There is a HN thread about that currently: https://news.ycombinator.com/item?id=17711717

Yes, hydrolysis could be a good solution. Create hydrogen and oxygen. The hydrogen could also be used in hydrogen cars that we have been talking about for decades.

More like 1 hour every 4 days in Germany, if I'm counting the number of hours YTD correctly.

Well, I did also say low not just negative.

I think there are huge benefits if power was charged at spot rates that were very visible (and actionable). IE its a warm sunny day with lots of wind, the thermostat will let you go down to 74 degrees with AC because power is cheap. If its a warm still evening, let it be warmer in the house to save money. Similarly, run the washer and dryer when its sunny and windy. If power is expensive this week maybe we can't take that weekend trip.

With your desal example, I think a bulk of the energy requirement for desalination is building a pressure differential. That seems like it would be very easy to parallelize.. you don't need full on duplicative Desalination sites, you just need pressure vessels that can store large amounts of compressed air to take advantage of energy gluts.

If you can store large amounts of compressed air to take advantage of energy gluts, it's probably better to just storing it and generate electricity to sell on the market when the price is high...

I thought they used electricity to deionize salt water, the salts are already dissociated into positive and negative ions, so pass a current through the water, and every now and then raise the electrodes out, mechanically scrape it off or reverse current in dump brine to remove the ions...

There are two major ways to do it at scale: Distillation, or reverse osmosis. In large plants they are actually energy competitive - reverse osmosis needs pumps to build pressure. Distillation needs energy to boil water, but then that steam is cooled down with the input water which gets heated in turn.

I'm not aware of any large scale ion plants, I don't know if the chemistry can work or not.


Or boil via vacuum

Doesn’t work. By the time you’ve moved any non-negligible amount of ions, you’ve built up an insane amount of charge and hence voltage. That voltage will be impossible to work with, not to mention many orders of magnitude higher than the voltage needed to split water into H2 and O2.

One mole of singly charged ions is ~1e5 Coulombs. At an insanely high capacitance of 1 Farad (which you’ll never see in such an application) that’s 100kV of static charge by the time you move a few grams of salt.

This is why you essentially never encounter ions by themselves.


I was thinking of https://en.wikipedia.org/wiki/Capacitive_deionization

I was wrong about the desorption step, I thought they scraped the ions off...

Incidentally at that page: "Part of the energy input required during the adsorption phase can be recovered during this desorption step. "

With enough of those electrodes, can't we use the sea as a big electrolyte battery? the energy is storedd capacitively


Could you store electrical energy this way more efficiently than pumped hydroelectric? Like make a capacitor the size of a wastewater storage tank?

There are devices called “supercapacitors” that work a little bit like this. They have rather weird electrical characteristics. I think they’re occasionally used as car starter batteries, but they’re mostly used as very long-lasting devices that can store a moderate amount of energy for backup use. I have a nifty DIMM with some supercapacitors that power a circuit that will wrote the contents back to flash if the power fails.

Wouldn't it self-discharge? And at that size, also blow itself up?

There are a lot of interesting Demand Response solutions that are also somewhat applicable/useful for this problem.

In a normal demand response scenario, when too many people are demanding energy, certain loads are turned off or scaled back (ACs/Thermostats/Water Heaters).

Water heaters in particular have been shown to have been one of the better time shifting solutions. Seems like you could do the same thing with both water heaters and AC systems as most buildings have quite large thermal masses. For AC its a bit lame because the hottest time of the day is the best producing for PV frequently so shifting can be tough, but perhaps around the beginning of the day and end of the day there is some opportunity to precool homes before people return and then back off as the price goes above 0, that sort of thing.


I used to work for Alstom Grid (now GE Grid), and I was kinda abstracted from specific use-cases, but we developed energy markets [0] that I believe are relevant to what you're talking about. Our energy market tools allowed companies to bid for electricity and schedule their work. So if you had an energy hungry rock crusher that can run at any time of day, you could buy or sell energy depending on the supply/demand curves. But apparently not every utility participates in the energy markets.

[0] https://en.wikipedia.org/wiki/Regional_transmission_organiza...


There's a northern German copper plant which can dynamically adjust its energy usage to the availability of renewable energy. If the availability is low, they reduce their production and thereby greatly help the grid. I could imagine plenty of large consumers to dynamically adjust their processes to the price of energy, obviously costs money to setup and maintain, but will be beneficial regardless with very fluctuating energy prices due to the intermittency of renewable energy.

It's a problem for infrastructure investors, or more precisely, investors in traditional power plants. Since most traditional power plants tend to produce CO2 and other pollutants, I'm actually inclined to think it's a good thing if economic incentives begin to turn against them. We'll still need power, and energy is big business, so there's tremendous incentive to solve any problems in that sector.

I guess this will maybe emerge in the future if the trend continues and is fairly steady. The problems I see is that the capital cost of many of the most energy demanding processes are such that they only make sense to run almost 24/7, and if the cheap electricity is only available 8/5 (or something) the economics might not work out. Maybe there are some applications out there that are cheap enough for this to be sustainable.

I think sustainable ammonia production would be a good fit.

https://en.m.wikipedia.org/wiki/Ammonia_production

> Ammonia production depends on plentiful supplies of energy, predominantly natural gas. Due to ammonia's critical role in intensive agriculture and other processes, sustainable production is desirable. This is possible by using renewable energy to generate hydrogen by electrolysis of water. This would be straightforward in a hydrogen economy by diverting some hydrogen production from fuel to feedstock use. For example, in 2002, Iceland produced 2,000 tons of hydrogen gas by electrolysis, using excess electricity production from its hydroelectric plants, primarily for the production of ammonia for fertilizer.


I suspect it would be difficult to find an energy-intensive process with sufficiently low capital costs that it would make sense to only operate--recouping some of the costs--when energy rates are negative.

>I understand storing the energy in batteries is currently very expensive economically and materially

From what I understand, they recently have gotten cheap enough that they are starting to be adopted on a large scale.

And one advantage they have over many alternatives is they can respond instantly, so they can be used to deal with the momentary shifts in the supply-demand balance that all electric utilities experience on a daily basis. As a result they save a lot more money than just dealing with the daily cycle.


I'd also think another challenge is the issue of timescales. "Green" energy sources like wind and solar can have large fluctuations, on the timescale of minutes. I don't know much about desalination plants, but I'd imagine they cannot be started and stopped just like that.

(This, incidentally, is a reason I've heard power engineers give for preferring natural gas to e.g. coal, aside from cost considerations: generators are faster to start and stop.)


One reason I am very dubious about the various alternatives to batteries that so many people are proposing is that there are lots of very smart people with lots of money behind them who are working on the storage problem, and a good alternative would be worth many tens of billions of dollars. If there was a good alternative, we would be seeing it adopted on a huge scale. My conclusion is the only workable solution is batteries, either lithium-ion or flow.


I imagine something like this would happen, if this is a "real" economic phenomenon rather than a quirky price/billing system. I think that it's something like that though, a goof in a not-quite-designed collection of old energy funding/billing setups and newer green energy stuff.

Otherwise there'd be someone just consuming electricity for pay. I don't think this is "retail."


the point is that "just consuming" the electricity is nontrivial. Suppose you've been paid to take some number of megawatt hours of energy. Okay: What do you do with it? At the least useful, you have to safely convert it into heat it without damaging something. More useful would be storing it. If you know how to solve that, yeah, you will make money.

I don't think it's that difficult, depending on how much power you're talking about.

You could literally attempt to boil the ocean, if you want to be ambitious. Heat your pool, for a domestic application.


Okay, go for it then. Good luck!

One problem with this idea is that storage keeps getting cheaper, so a plan like yours that could be a good investment for present storage costs probably wouldn't make sense in a few years, and all that capital investment you hoped would be paid off over ten or twenty years would be lost.

Desalination is AFAIK energy AND capital intensive, so it's very expensive having such equipment sitting around doing nothing until energy prices fluctuate low enough.

Now, there are situations where demand response makes economic sense; just not enough by far to balance a huge amount of variable renewables.


I think that usually, stuff like desalination plants aren't over-dimensioned but are built to consume some known amount of power. There's nothing to consume near-free power because that capacity would sit idle the vast majority of time.

If they can produce so much cheap energy, doesn't that balance out with the more expensive batteries they have to buy? (which will only get cheaper in the years to come)

there is the crucial difference that batteries wear out, so you have to buy new batteries.

storage space for products or bulk matteer does not typically wear out (or not nearly as fast).


To reverse the process we can then run an osmosis power plant and have a way to store energy. I'm sure someone out there already ran the numbers.

Why don’t we just move all our solar panels 8 hours to the West?

time to spin up some giant flywheels.

I think the issue is, many regions in the U.S. operate on real time energy pricing markets. Generation companies get paid for what they produce based on these energy prices. When prices go below zero, they have to pay to produce.

The only groups that can afford to do this, are one's who can use clean energy government subsidies to bid in their cost of production at below zero, and essentially pay to produce energy on the power grid.

If you think clean energy should get a preference on the powergrid for dispatching energy, that is fine, and many places in Europe do it well and reliably. However, in this case, real time energy markets are probably not the best reflection of what incentives are truly at play.

An example of this is that clean energy gets an unfair advanatage in that it's weaknesses are not exposed. It is good to provide an economic incentive for the generators to need to perform better.

An example of this is wind plants in NY. They get energy subsidies for producing power, but not necessarily producing power on the power grid. So they can create energy, and never supply anyone with it, and get subsidies per MW for this. You might think the best way for them to double their income by

1. getting subsidies and

2. actually getting paid back the real time energy price on the power grid

would be by supplying power when it's needed by buying batteries and putting that energy they create (when the wind is blowing at night for example, when noones needs it) into the power grid when demand is high, at maybe 5pm on a hot summer day when everyone has their ac cranking, but it turns out that costs money? And they are already getting free money. Some power plants are starting to do that, but they could have easily done that a decade ago.

I believe we should have clean energy, and do what it takes to get there, that's why I specialized in Electric Power, but I think the way it's currently set up in the real time markets creates some preverse incentives that hinders optimisation in the field.

While clean energy is nice (solar panels, wind turbines) they could use alot of improvement on their efficiency and integrate batteries into their substation design. Many do not because it is too profitable as it is.

It's also important to note the people getting paid these subsidies are venture capitol firms funding these clean energy substations. They are not green tree hugging people, and most of the companies have an incredibly diverse portfolio that does not reflect a loyal dedication to clean energy cause. The profits they receive from these government funding go back to VC firms to be reallocated to...well.. whatever they see fit and many times it has very little to do with powergrid stuff at all, much less clean energy. This is free money for venture capitalists...think about that.

It's a very interesting market because people's idea of ethics and moral rightness are able to blind some very basic abuses in the system that degrade the performance, reliability and overall amount of clean energy produced on the power grid.


Bitcoin mining. This may or may not be a sincere suggestion.

Same flaw as the other ideas - mining is very capital intensive. You can use mining in a demand response capacity, but it's best used when you can run it 98% of the time and shut down during the most expensive 2%. If you look at some of the data from Australia, peak cost per MW can go really high.

It's also an environmental travesty, but that's already the case.


Remember that the alternative at the moments is literally pumping that energy into the ground as waste heat. I think that renewable resources otherwise wasted being used for mining instead of that seems like a win-win.

It takes resources - a lot of them, including energy - to build the miners. It's a net loss if you can't run the miners at a sufficient duty cycle. Cheap mining power is about 4c per kwh. A $350 GPU at 200W (hand-waving) takes about 20c/day to operate. At $70/year of power, and maybe a useful life of 3 years, it's actually capital-dominated.

True- so if you lived in a zone with negative price, then you would throttle your GPUs otherwise and only go full throttle when you literal get paid to use the power. But duty cycle just for that would be low... I would need to look more at the stats. But if full time operation on average over the year was closer to (or less than) $0 for power usage, could you net a profit over the life cycle? I would surely hope so!

> It’s left the utilities complaining that they can’t earn the returns they expected for their investment in generation capacity.

Good. That's a well functioning market economy. Those who make poor investment choices need to feel the sting of losses else the market fails to work correctly.


Low/negative prices (caused largely by various regulation/policies) have been putting a lot of economic pressure on existing nuclear power generation - sometimes causing it to close [1]. Generation that is largely replaced by natural gas plants. So maybe this very non-free-market state is actually not helping make forward progress on what many would consider to be one of the most important issues relating to energy - climate change.

[1] https://www.forbes.com/sites/jamesconca/2016/05/16/natural-g...


An energy industry where the bulk of energy production is wind & solar with natural gas plants to handle peak demand spikes is significantly more environmentally friendly than an industry where the bulk of production is oil & coal with a few nuclear plants thrown in.

Neither of the alternatives you propose are what we currently have or are where we are currently heading (IMO). As long as we are speculating - I think a future with good storage tech and 100% solar+wind would be better than one with gas plants thrown in the mix. If climate change is as big a deal as people claim, than why would we sacrifice existing non-carbon-emitting capacity for natural gas? We don't currently have anything remotely resembling a largely renewable grid nor the technology to even accomplish it at scale.

The article suggests that solar + wind with natgas for peaks is exactly where we're headed. At least in the regions being talked about (mostly Europe + California).

The Forbes article you linked is about New England. New England will probably be the last region to get decent renewable adoption. Solar panels don't work as well because they're far north and get a number of cloudy days, the winds are not that strong outside of the Cape Cod and certain parts of the Maine shoreline, and there are few rivers that are suitable for hydro.


> New England will probably be the last region to get decent renewable adoption. Solar panels don't work as well because they're far north and get a number of cloudy days...

Wrong. Most of Europe (especially Germany) is actually at a higher latitude than New England.


...but tends to be windier. My understanding is that renewable use in Germany is largely driven by wind power.

Germany has 5 times as much solar capacity as wind power, and the highest PV watts-per-capita in the world.

https://en.wikipedia.org/wiki/Solar_power_by_country

https://en.wikipedia.org/wiki/Wind_power_by_country


The chart you linked to shows wind at 45GW in 2015 and solar at 41GW in 2016, and this page [1] shows net generated energy in 2016 at 77TWh for wind and 37.5TWh for solar. Are you sure you weren't looking at the "New installed capacity" for wind and comparing it to the total capacity for solar? (The solar numbers are admittedly bigger than I expected to see, though it appears that wind is growing 4x faster than solar, which is the opposite from the U.S, where the installed wind base in greater but solar is growing 2x faster.)

[1] https://en.wikipedia.org/wiki/Renewable_energy_in_Germany


I cited natural gas being used for baseload power. In the last several years, gas has been installed frequently as baseload generation.

All I'm saying is that I think governments' approaches to incentivizing energy production are very suboptimal for mitigating (negative) effects of climate change. And negative energy prices are one of the red flags that this is the case.


FWIW, my understanding is that the bulk of the baseload natural gas plants are being installed as replacements for older coal plants that are being decommissioned.

Considering that the latest project to construct new nuclear plants in the USA nearly put Toshiba - like, the whole company, not just their power plant division - into bankruptcy, I'm not certain, on purely economic grounds, how realistic an option "more nuclear" is.


Toshiba was hit because they acquired Westinghouse, I remember reading that Westinghouse had some accounting irregularities before the acquisition that then Toshiba continued until recently.

I don't think it was the projects and the cost of them themselves but previous underlying problems in the companies.


The big problem was that Westinghouse signed a contract that put them pretty much exclusively on the hook for cost overruns, without any good way to get out of it. That explains why it hit them so hard, but it doesn't necessarily explain the cost overruns in the first place. A lot of that can at least be partially explained by other, deeper problems. For example, they kept reworking the design even after breaking ground, which seems symptomatic of the loss of engineering expertise in the field over the past few decades.

The whole saga has also led to two major manufacturers - Toshiba and Westinghouse - exiting the market, which I'm inclined to take as an omen that, at least in the North American energy market, a lot of these deeper problems can be expected to worsen instead of getting better.


Natural Gas "Peaker" plants are VERY expensive to run. (Mainly because of their low utilization compared to high costs). In many cases, battery storage is already cheaper than peaker plants.

Regarding the cloudyness... Has anyone ever tried to levitate photovoltaics into the stratosphere? Blimpy-space-elevator kinda thing? Is such a thing even possible?

I looked into this in a lot of detail about 5 years ago. There were a couple of studies, and one somewhat-active company I saw (Stratosolar - didn't seem to be very well resourced/capable).

My main focus was on aerodynamic modelling and panel positioning methods for various structure sizes, and the resulting LCOE. Main issues I found were: - Weather conditions in the stratosphere aren't well understood; most of the time pretty benign, but there are a bunch of extremes which could have a significant impact on the structural requirements. - It's basically a tradeoff of panel-cost/conventional-installation-cost vs aerostat-cost/non-conventional-installation-cost. The aerostat is definitely not going to be cheap, so having your panels on an aerostat has to result in a bunch more energy per PV-element than having them on the ground. - Having the aerostat option come out on top gets more difficult as PV gets cheaper. Let's say you get 2x energy from PV on an aerostat vs installed on the ground. That means the aerostat option will be competitive with the ground option as long as the total installed cost (per watt) is less than 2x the terrestrial installed cost. If the terrestrial installed cost reduces by a factor of two (and it's reduced by more than that since I did the analysis!), you suddenly have to reduce the marginal cost of your aerostat option by 50% just to remain competitive! - To be economic and sufficiently robust to expected weather, these structures have to be enormous; the architecture that seemed most promising to me (from memory) was cylinders of length 4km and diameter 1km (roughly 1GW electrical output peak, more like 500-600MW annualised). They're at least semi opaque, and are tethered around 20km altitude (and can drift within a ~10km radius around the tether point). At that altitude they're visible from several hundred kilometers away, and they look huge - 15x the width and length of the largest cruise ships. - It doesn't help THAT much with seasonal variation away from the equator. Summer output in northern europe is still 2-3x winter output, so you need long term storage or an energy dump.

So... I think it's super interesting, but I don't think it'll ever be commercially attractive vs either terrestrial installations, or space. The main nice thing is that it's still pretty easy to get the power back down to earth with high efficiency... in contrast to orbital solar.


Gah, what a formatting train wreck :-/ sorry...

Don’t apologize, this is super informative! :)

I feel like it's far easier just to transmit it 1000 miles or so from a sunnier place.

Not necessarily, because 1000 miles of a transmission line is a lot of metal, land, construction, and electricity losses.

Unfortunately, a power station at 100-200 miles above Earth, where sunshine is eternal, and which is relatively accessible, will not stay above the same spot, and GEO is way high (22k miles) and thus even more expensive to build at (and already pretty crowded nevertheless).


I think battery storage peaker plants are where we are going, like the one in australia that tesla built.

Yes, but we want the coal to be displaced. Not the nuclear.

Coal already has been displaced. The reason there's less of a downturn is because there's a lot less of it to begin with:

https://www.iso-ne.com/about/key-stats/resource-mix/

There's 20x more nuclear than coal energy in New England. Proportionally, the drop in coal energy (~50%) was a lot more than the drop in nuclear energy (~15%).


I'd much rather have solar/wind/nuclear than solar/wind/gas.

I would too, but that's not a possible combination. The issue is that at any given moment, the amount of electricity produced must equal the amount consumed. Solar and wind have production curves that are defined by the sun and wind, and typically peak early morning (for wind) and mid-day (for solar), which are often not the times of peak demand. So when everyone turns on their lights, TVs, stoves, and laptops in the evenings, there needs to be a quick-responding power plant to meet the excess demand. By far the preferred technology for this is a natural gas turbine, because it's one of the few technologies that can adjust its output within seconds. Nuclear power plants take several hours to days to respond to shifts in demand, because the control rods must be moved, the nuclear chain reaction must speed up, it needs to generate more heat, that heat needs to boil water, and the steam needs to make its way to the turbines.

There's more information in the wikipedia pages for "base load", "load following", and "peaking" power plants:

https://en.wikipedia.org/wiki/Base_load

https://en.wikipedia.org/wiki/Load_following_power_plant

https://en.wikipedia.org/wiki/Peaking_power_plant

Interestingly, solar-thermal is apparently coming online as a potential technology for peaking power plants, which could reduce the need for natural gas.


Afaik the problem is that the currently installed nuclear generators cannot stop their operation in the middle of a fuel cycle.

The green fantasy of renewables + nuclear doesn't work with the current generation of nuclear power plants. US nuclear plants either run at 100% power, or they are shutdown for refueling. That's pretty much the only way they are economical.

If negative externalities such as carbon were properly priced, the dynamics could possibly change (guessing, I'm not quite sure what a fair price on carbon would be, and what the difference in price between nuclear and natural gas is)

HN seems to have some macho fascination with nuclear power. Or at least that's the only reason I can think of why people would advocate for it, considering nuclear power is simply far too expensive.

Yes, maybe the population at large lacks statistical understanding and needlessly fears nuclear power[0]. But it's still too expensive, as demonstrated by the complete lack of new construction. It'd be rather strange for every single energy company and government to succumb to irrationality, simultaneously.

Even solar + storage has now crossed nuclear's costs. I

[0] And they may just have all read 'Black Swan'


I don’t know why you’re getting downvoted, it’s 100% about cost. It’s far too expensive, and the ROI horizons are far too long (multiple decades)

Edit: and that’s only if you cut a nice deal where the state picks up the insurance tab, because private insurance markets aren’t going to.


> I don’t know why you’re getting downvoted

Probably the oddly aggressive "macho fascination" bit.


> macho fascination

What does this mean?


Investment into traditional generating capacity is not a "poor investment choice." To the contrary, it's a necessary one. For better or worse, a fundamental premise of modern electric grids is that they should be able to meet all needs essentially 100% of the time. Electrical markets are then built on top of that basic guarantee.

With current technology, that means you need sufficient generating capacity from traditional sources to cover nearly 100% of your peak capacity needs--otherwise, on a day where the wind isn't blowing and the sun isn't shining, you can't produce enough electricity.

Current renewables subsidies results in a broken market structure: the market needs conventional generators, but the subsidization of renewables makes it unattractive to build those generators. A "well functioning market economy" does not eliminate incentives to produce products that people need.


There are two things happening, both because of the negative externalities that traditional sources produce, but aren't factored in to prices. One is subsidies, the other is source prioritization both of which favor renewables. Plants that can provide that peaker gap on windless+cloudy days should be rewarded by the market by very high kwh purchase prices, but that's all. The current benefits that renewables receive are aligned with the true costs. Alternatively you could replace the prioritization and subsidies with a heavy carbon tax on traditional sources but the result would be the same.

> The current benefits that renewables receive are aligned with the true costs.

So energy storage / building heavily underutilized plants is free in this theory?


No, it comes at a severe cost. The upside is that it removes the negative externalities of legacy plants.

Not only is this good, this is great! Hitting negative energy rates just incentivizes more and better storage technologies to accelerate. We need more grid-storage online fast and nothing could incentivize storage tech more than being paid both ways for electricity management. Get paid for storing it during the day and get paid for delivering it at night. It's not the best case for power plants right now, but once this new grid storage market settles the double-incentive will go away and things will even out a lot more.

I think that negative prices are prima facie evidence of a market economy not functioning "well".

Negative prices seem to me to be to be equivalent to fines for doing things that aren't socially useful. If they proliferate, that's a suggestion something is out of whack.


It's certainly not a free market economy because almost every electricity utility is a state monopoly.

When markets get "out of whack" it's almost certainly due to government regulation. In this case, it's the government setting fixed electric rates for consumers.

It depends on whether or not someone is able to demand delivery at that price and what other forces are in play. i.e. presumably there are regulatory requirements that some minimal amount of capacity must be available as generators typically can't quickly spin up based on the whims of the sun/wind... but what if the generator provides it and there are no takers which a zero/negative price would indicate? Of course that's not sustainable for long it becomes a persistent situation: at some point the generator must be subsidized, or can absorb a loss over brief periods for the 'privilege' of being a provider the rest of the time, or goes bankrupt.

Running parts of businesses at a loss isn't unheard of provided the governments responsible for overseeing it are OK with and/or mandate it (a wide variety of services to rural customers here in the U.S. comes to mind) and the impacted business makes up for the loss elsewhere.


"Running parts of businesses at a loss isn't unheard of"

A negative price seems fundamentally different than just running at a loss though.


Negative prices a perfectly possible in the ideal free market. The market of course requires the overall prices be positive, but given the very low ongoing costs of wind/solar it makes sense to build even if prices are sometimes negative - the alternative is to shutdown, but then the wind/solar operator needs to do something with that power, which in itself has costs. So long as the times the times of positive prices balance out you are fine with some negative.

In addition, there is probably some advantage to encouraging other parties to develop uses for cheap power as part of long term planning.

Of course as others point out nothing is every an ideal market.


I admit I’m confused by negative pricing. Presumably solar can be curtailed for free.

But with something like wind, I think production is all or none, and switching back and forth is a bit slow. It’s more economical to pay a tiny amount to get someone to dump the power.

On a smaller scale, it’s common for off-grid hydro to have a giant heater waste power as needed.


You are right, although it's not clear for me if you refer to the old/traditional coal plants or not. If you refer to the coal plants I agree, the 'negative prices are prima facie evidence of' coal plants 'not functioning "well"'.

Only if they stay negative

That's reasonable. The headline says it's spreading though.

In this case "spreading" means "happening more often". And you could have a stable rational market where power prices go negative for an hour every day.

It's spreading because the market is oversatured with renewables because of government subsidies. A sound investor would stop (or go bankrupt) when the negatives outweigh the positives.

Subsidies seem to be on the decline. In fact, I was just reading that due to the Chinese government cutting back, people are predicting PV prices will plummet in the next year.

For many utilities, it's not as simple as that. They're heavily regulated and their prices are generally set, capped or otherwise limited to give them a certain percentage profit. They often have to get price increases approved by their regulators. If they have debt outstanding on underperforming gas power plants, they may need to make this argument publicly so they can adjust pricing.

You're referring to distributors, the energy companies that are responsible for managing the wires/gas pipes to your house (Think ConEd, EverSource, etc). This effects the energy generators, which don't have prices regulated but are still regulated by FERC.

> Good. That's a well functioning market economy. Those who make poor investment choices need to feel the sting of losses else the market fails to work correctly.

You say that - up until the day there is a brownout on a cloudy, yet boiling hot day, because there is little sun and no wind, and no one wants to build non-economical power plants.


FTR i also believe there should non-regulated prices. If the price on that day goes up to $1/kwhr (or whatever) so be it. The market prices incentivises the right solutions to problems

eg: batteries and home generators for cloudy days for those who _must_ have power, but those who see the price is $1/hr will turn off their TV or dishwasher etc.

or maybe consumers will start to buy contracts from plants like "I will use 1K of continuous power if you provide it at 16c an hr"


Exactly - this will finally make them think twice about installing more generation capacity and will force them to consider installing battery storage or other solutions to fix issues on the grid.

These non-generation solutions exist, but utilities love to just install more generation because it's in their playbook and they don't want to innovate.


> utilities love to just install more generation because it's in their playbook and they don't want to innovate.

I'm curious, how did you reach this conclusion?


Utilities make a guaranteed rate of return (up to 10%) when they build new generation plants and when they build new transmission lines. This is payed for by rate basing the new costs to customers. The system works great for utilities because they know how to build these plants/wires and the get paid regardless of whether they are truly needed or not.

Local governments and state regulators have finally started to push back against and are now forcing utilities to consider new solutions to grid congestion. https://www.utilitydive.com/news/non-wires-alternatives-what...


Electricity isn't a great market. End-users with solar power are allowed to use the grid as a perfectly free battery, which is why everyone is dumping power on the grid at high noon.

Where I live its about 25c (of Australian Dollar) for 1kwh but you only get 7c back. So a real battery would be much preferable.

> Where I live its about 25c (of Australian Dollar) for 1kwh but you only get 7c back

I've read about places that don't actually do "net metering" and implement this with two separate meters, one for inflow and one for outflow.

Is that the case where you are? Are there any time-of-use options available that might sweeten the deal?

> So a real battery would be much preferable.

Assuming it were free (even to purchase, with only charge/inverter efficiency losses), of course it would. However, as much of the discussion in the thread points out, storage is very capital (if not maintenance) intensive, even at utility scale.


It doesn't need two meters, you can just keep separate track of the times that the connection is a net exporter and the times it is a net importer.

That's true, in that, if the metering is purely electronic, the only thing "separate" would be two different readouts. For electro-mechanical metering, I'd still expect a need for two physically separate ones.

Regardless, substituting "readouts" for "meters" is irrelevant to my question.


Its a single digital meter.

For a few weeks we had the old style meter. It span backwards on a sunny day. So for that time period it was same rate in and out.


Due to subsidies, in the US people dumping home solar into the grid usually get back more than the market rate.

I don't think that's the case. Depending on where you are, you either get paid retail or wholesale rates, and still have to pay some monthly service fee regardless of surplus or deficit. I've never heard of any utility in the US buying solar production at more than retail rates.

> you either get paid retail or wholesale rates

So above market rates. Sorry, your 10kw of intermittent unreliable power provided at your whim into a random neighborhood grid is not worth the same amount per kwh as reliable base/load following generation. And that's wholesale.

Retail priced net zero metering is even worse - that's simply poor people subsidizing rich folks with solar panels.

Maybe the subsidization is ok overall due to the system changes it (might) bring about - but man it's bothered me for decades that rich folks who can afford to blow $25k+ on solar installs act so smug about net-metering - when it's them simply stealing from other ratepayers for their free battery.


> I've never heard of any utility in the US buying solar production at more than retail rates.

That doesn't refute the parent's claim of it being greater than the market rate. The residential retail rate [1] usually doesn't change, except on a long time scale, after regulatory approval, while the market rate changes intra-day, based on supply and demand.

If peak sun doesn't correspond to peak demand (and, from what I've read, it doesn't), those periods are where the utility could be taking a huge loss. For example, if PG&E has a customer in the top marginal usage tier is "selling" power at 25c/kWh when the wholesale market is selling it at 4c, that's a pretty tremendous loss.

[1] Often not even a single rate but a tiered one, so a heavy residential user could be "selling back" power at a particularly high retail rate, much higher than average.


End-users who produce electricity aren‘t a problem for the grid, they produce electricity very close to where it‘s mostly consumed (typically they consume most of it themselves). Wind farms on the other hand are built where it‘s cheapest and yields are best, often far away from any relevant consumers.

With their own batteries for 24h+ (soon...), end-users will be the best thing that can happen to the grid.


> Good. That's a well functioning market economy. Those who make poor investment choices need to feel the sting of losses else the market fails to work correctly.

Unless it affects grid reliability. Energy is not just a market. It's something that underpins modern society and the modern economy. I, for one, do not want my power to go out at 7pm because demand is peaking, traditional plants had to close, and the sun is going down.


You've defined a rapid peaker plant, which no one is implying we should lose. The destruction of the market for this type of bad-actor legacy baseload is a market opportunity for those who can provide the services you're talking about. Whoever can provide it should earn a premium for doing it.

It is well functioning economy, but is it good for the environment, CO2 emissions in particular?

Because with negative electricity prices, the obvious "good" investment is in peaking power plants. And considering that the best spots for hydro are already well exploited, it means fossil fuel. Natural gas is the best but newer coal plants, like the one they are building in Germany can do that to some extent.

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