This solar farm has to switch off every second day due to negative prices - Page 1
Forum section: electronics / general

author: BBBbbb
author_rank: Unknown
timestamp: November 07, 2019, 12:01:34 pm
content: https://reneweconomy.com.au/this-solar-farm-has-to-switch-off-every-second-day-due-to-negative-prices-63529/Some thoughts:- This could be a great tool to penalize the non-green sources (coal, gas) that can't switch off on the cheap, and end up getting hit by the negative prices.- OTOH these agreements are confidential, and since the non-renewable sources can provide stable and weather independent supply they could easily negotiate a lot better conditions, meaning no negative prices, so without sufficient "hydro batteries" I doubt the pressure is meaningful on non-renewable sources

author: Marco
author_rank: Super Contributor
timestamp: November 07, 2019, 03:28:00 pm
content: Time to mine and refine more aluminium.

author: bdunham7
author_rank: Super Contributor
timestamp: November 07, 2019, 05:59:11 pm
content: There's nothing surprising or wrong about this. Obviously with a zero incremental cost, the solar plant would like to sell all of the electricity it can produce, but there will never be an exact match between capacity and demand. When the price of the commodity goes below the cost of production, you turn the system off. Since the only way you can have sufficient production all or most of the time is to have surplus capacity, it seems obvious that at times some capacity will not be needed. When solar was a small part of it, other non-zero incremental cost producers would drop offline first. As solar and wind become larger, curtailment will become the normal process for managing the grid. At least it is easy and quick to turn on and off!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 07, 2019, 06:06:02 pm
content: Quote from: Marco on November 07, 2019, 03:28:00 pmIt would be interesting actually to put it into an aluminum battery of some sort. Unfortunately the Hall process demands continuous operation at scale; indeed, it's usually run on hydro.Aluminum electroplated out of some kind of organic carbonate solution (analogous to getting lithium metal out of an overcharged ion cell) would be interesting, though I wonder if it could end up anywhere near economical anyway. (And in any case, energy storage is better with alkali metals, no need to try and sell an already quite cheap industrial metal out of it, etc. etc...)Tim

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 07, 2019, 06:20:42 pm
content: Any engineers know of a way of converting CO2into a solid? This would be a rather green way of using the over capacity by directly or indirectly removing atmospheric CO2and then, selling this carbon capture on the global carbon trading market. Yes New South Wales, you can tax that. Maybe even make hydrogen for fuel cells? Or just mine Bitcoins on 'negative' electricity days? Otherwise it's a tragic waist of sunlight.

author: coppice
author_rank: Super Contributor
timestamp: November 07, 2019, 06:29:11 pm
content: Quote from: T3sl4co1l on November 07, 2019, 06:06:02 pmMost aluminium used to be produced in countries with surplus hydro power. Look at the global production figures now, and you'll find most aluminium is produced in China, where there is a massive shortfall in renewable power. They are the world's biggest installer of renewables, but they have a long way to go to wean aluminium production off fossil fuels.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 07, 2019, 07:30:08 pm
content: Quote from: Syntax Error on November 07, 2019, 06:20:42 pmIt is pretty hard and energy inefficient to remove CO2 from the atmosphere as the concentration is so low. For the forseable future it is much more advantageous to remove it from waste streams where the concentration is much higher.In terms of fixing CO2, there are basically two options: 1) carbonate minerals. This is attractive because it doesn't require massive energy input. This is how geological carbon sequestration works. The downside is that you have to mine a ton of uncarbonated minerals. We actually mine carbonated minerals (calcium carbonate) and extract the CO2 in order to produce quicklime. 2) hydrocarbons. This doesn't require any particular mining, but again we currently mine hydrocarbons and burn them, so this doesn't make a huge amount of sense to do the reverse process.

author: daqq
author_rank: Super Contributor
timestamp: November 07, 2019, 07:43:09 pm
content: QuoteNot sure about solid, but carbon capture is a thing. Don't know how efficient it is.http://www.climeworks.com/our-technology/

author: Retep
author_rank: Regular Contributor
timestamp: November 07, 2019, 07:45:39 pm
content: Quote from: Syntax Error on November 07, 2019, 06:20:42 pmGrow a tree?

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 07, 2019, 08:55:28 pm
content: Quote from: Retep on November 07, 2019, 07:45:39 pmIsn't photosynthesis clever? This might work as a concept if the excess electric is used to power pumps to irrigate crops or even a forest. But then where does all the water come from in a desert where solar farms are often located?Quote from: daqq on November 07, 2019, 07:43:09 pmSucking air through carbon eating filters might work, but I doubt there are economies of scale when you calculate how much C02is produced making the fans in China or India. Idea for a Kickstarter/Snakeoil project; fit carbon eating filters on all kinds of extraction fans around the home. A million dollar$ please.Quote from: ejeffrey on November 07, 2019, 07:30:08 pmAgreed. I wonder if they'll ever worry about the levels of CO2on Mars?It's a crying shame that all of his sunlight goes to waste, but that's just the "the market" for you. Expecting governments, state administrators, industry and private venture capital to use joined-up-thinking to mitigate climate issues is not going to happen anytime this century.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: November 07, 2019, 09:01:30 pm
content: The other chemical pathway for energy storage is Ammonia. Ammonia can be burned, or put through a fuel cell or sold as fertilizer in liquified anhydrous form. Farms could be made entirely self powered.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 08, 2019, 03:18:23 am
content: A reasonable way to make use of the "extra" energy is to pass through the savings to customers. A large part would be to leverage existing thermal mass as storage, e.g. set water heaters to a higher temperature, run HVAC equipment more, set freezers to minimum temperature.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: November 08, 2019, 12:27:00 pm
content: Quote from: NiHaoMike on November 08, 2019, 03:18:23 amIn Canada I think this already being tried in a small way, I heard Nova Scotia or PEI has some kind of smart water heater program but I live on the opposite coast so not sure.. It is easily implemented with an IOT controller that checks in with the power utility and requires very low incremental infrastructure costs. Easy win.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: November 08, 2019, 02:10:29 pm
content: I don't know about using excess power to remove CO2directly but there are plants using excess power to generate hydrogen which is then fed in to the gas grid.https://en.wikipedia.org/wiki/Power-to-gas

author: Marco
author_rank: Super Contributor
timestamp: November 08, 2019, 04:44:52 pm
content: Quote from: T3sl4co1l on November 07, 2019, 06:06:02 pmEverything needs to be kept molten, but that can probably be done with far less power than electrolysis itself. The plants weren't designed with as hugely varying power costs as we have nowadays, there is obviously huge inertia given the capital and R&D investments involved but I expect intermittent plants at some point. Even if none of the alternative reduction methods bear out.It's solidified electricity, if you can make it and even get paid for the electricity you're consuming you're golden.

author: Someone
author_rank: Super Contributor
timestamp: November 08, 2019, 10:20:40 pm
content: Quote from: NiHaoMike on November 08, 2019, 03:18:23 amThis is significant "low hanging fruit" in the possible ways to develop demand responsive grids.VarioussourcesclaimHVAC alone is a significant part of the total energy demand so its not like the well funded yet minimally effective efforts to change to high efficiency lighting. Sadly very few customers are exposed to the wholesale market so many efforts so far have been by pooling resources through a wholesale market participant, who acts as a middle man and takes all the profit.More encouragingly energy for heating is dominated in "developed" countries bylow temperature demandwhich is easier to deliver/store or simply produce at low cost from renewables. Long term storage is still more expensive than oversizing the generation capacity there, so market fluctuations with negative cost periods are probably a healthy sign.

author: Marco
author_rank: Super Contributor
timestamp: November 08, 2019, 10:57:01 pm
content: Easier to store, yes. Easier to deliver, hell no. Only a small subset of houses have district heating, they pretty much all have electricity.

author: Someone
author_rank: Super Contributor
timestamp: November 08, 2019, 11:14:38 pm
content: Quote from: Marco on November 08, 2019, 10:57:01 pmNote the conjunction:Quote from: Someone on November 08, 2019, 10:20:40 pmStore and deliver, as in deliverable. Delivering low temperature deltas is much easier, particularly from local thermal storage.

author: Simon
author_rank: Unknown
timestamp: December 14, 2019, 10:49:04 pm
content: I was paid to use electricity last weekend.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 14, 2019, 11:32:31 pm
content: Industrial, larger consumers already see the variable costs and some cases they already make a good use of it (e.g. large scale cooling). It may need extra investments to get the production more flexible. To some degree this may also work with aluminum production, though this may not be the most efficient case. There are also some facilities that shut down in times of high demand (e.g. during winter or heat waves in other areas) and thus lower the need for storage this way. This could probably also be done with aluminum production - shut down for those months were the supply is usually short - this would replace long term (e.g. summer to winter) storage.With many small users (like private freezers) there is the problem of how to control it reliably. Such a control system showing glitches could bring down the grid, if it is doing the wrong thing. So it is not an easy thing.For storing carbon there is the option to use plant growth and make some kind of char coal, that can be stored in stead of getting burned. So kind of coal mining in reverse. So probably stop coal mining first. At least the plants could be used to get concentrated CO2, when pants are burned to produce energy.

author: David Hess
author_rank: Super Contributor
timestamp: December 15, 2019, 02:55:29 am
content: Quote from: BBBbbb on November 07, 2019, 12:01:34 pmThe Sierra Club actually had that as an bonus when enacting renewable energy laws in California a couple decades ago. Keep in mind that it affects nuclear also.If you penalized dispatchable energy sources enough, then they will not be available when you need them, as California is discovering. These laws are specifically intended to lower the capacity factor of dispatchable energy sources, especially nuclear, making them less economical. California and countries like Germany have ended up exporting their dispatchable energy demand to neighboring states and countries.And if you think batteries will solve that, they cost as much as a nuclear power plant with the same capacity but provide less capacity factor as California also discovered which is why they did not purchase battery capacity commensurate with their renewable energy capacity.You have to wonder about a political process which creates incentives to make money by installing megawatt scale toaster ovens.https://slate.com/business/2015/09/texas-electricity-goes-negative-wind-power-was-so-plentiful-one-night-that-producers-paid-the-state-to-take-it.html

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 15, 2019, 03:06:38 am
content: Quote from: David Hess on December 15, 2019, 02:55:29 amThe current California energy crisis is due to aging/neglected/unsafe infrastructure. That might shift things in favor of batteries, as in perhaps it would be more economical to convert houses to off grid or neighborhoods to microgrids than it would be to build new, safe transmission lines? With the current situation already getting the ball rolling on residential storage, it's only cutting into the funds utilities would have to rebuild with, and any attempt they might try to recover that will further push investment in residential storage+solar.

author: David Hess
author_rank: Super Contributor
timestamp: December 15, 2019, 03:14:41 am
content: Quote from: NiHaoMike on December 15, 2019, 03:06:38 amCalifornia is disfunctional in may ways but shutting down power plants so that they had to transmit power over longer distances did not help the situation. This is the state which legislated fixed wholesale but variable retail power prices and then blamed deregulation. The legislature knew exactly what it was doing when it created the Enron fiasco.

author: grifftech
author_rank: Frequent Contributor
timestamp: December 16, 2019, 04:46:43 pm
content: solid CO2= dry ice

author: Red Squirrel
author_rank: Super Contributor
timestamp: January 08, 2020, 01:53:00 pm
content: Wonder how feasible it is to store dry ice for long periods of time (days or even weeks). Could be interesting to store it, then use thermo electric generators in addition to the pressure it creates in a tight vessel to generate power. Would be a way to store excess energy to use it later. This would not be very efficient, but if you are using spare free green energy that would be wasted anyway, efficiency is less critical.

author: tszaboo
author_rank: Super Contributor
timestamp: January 08, 2020, 11:11:36 pm
content: Quote from: DenzilPenberthy on November 08, 2019, 02:10:29 pmP2G is an ingenious solution, that could solve the current storage problem.CO2 + 2 H2O = CH4 + 2 O2You can store enormous amount, and just burn it when you need energy in a natural gas plant.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 08, 2020, 11:21:45 pm
content: Quote from: NANDBlog on January 08, 2020, 11:11:36 pmHow much does it cost and how much energy.

author: coppice
author_rank: Super Contributor
timestamp: January 08, 2020, 11:25:47 pm
content: Quote from: NANDBlog on January 08, 2020, 11:11:36 pmThat's a very obvious method. Its just the Sabatier reaction, which many of us learned in high school chemistry. However, its not currently very efficient. The ingenious stuff is the work that is happening now (assuming it succeeds), that promises to raise the efficiency substantially, and could make methane production the holy grail of energy storage for a renewables network.

author: Whales
author_rank: Super Contributor
timestamp: January 09, 2020, 12:54:06 am
content: The whole idea of performing carbon capture with power, even positive-price power, seems silly to me. Reasoning:If we assume that the negative-price power is almost completely provided by burning sources (ie assuming all the renewables can quickly spool down to zero output) then we can imagine two pathways to using this power:(1) Power generated (CO2 released) * eff -> Aluminium smelter (aluminium made) * effvs(2) Power generated (CO2 released) * eff -> CO2 capture * eff,then someone else doesPower generated (CO2 released) * eff -> Aluminium smelter (aluminium made) * effIf we set a fixed CO2 budget for both of the above equations: the top version yields more aluminium. Ie it has better aluminium vs CO2 efficiency.If we assume that the market for aluminium is fixed (not true, but perhaps a good enough approximation) then it's more environmental friendly to use the negative-price power to make aluminium (or any other known/guaranteed useful good) than it is to try and use it for CO2 capture. Path (2) is less efficient than path (1).Conclusion: operating an electrically-powered carbon capture system is guaranteed wasteful unless you have no option of operating a profitable goods-making business instead. (Complexities like smelter thermal mass & operational requirements ignored)Thoughts?

author: coppice
author_rank: Super Contributor
timestamp: January 09, 2020, 02:15:58 am
content: Quote from: Whales on January 09, 2020, 12:54:06 amYour example is one where energy can be used at any time. A suitably designed aluminium production plant can keep ticking over as long as you don't starve it of energy for so long that it freezes. You have quite a bit of flexibility to use lots of energy when plenty is available, and less when there is a shortage. However, most uses of energy have to be timely. The need to store renewable energy in times of plenty, for use when renewable output is weak is the biggest challenge in expanding the deployment of renewables. Things like pumped storage are currently more efficient than the CO2->CH4->CO2 cycle, but hard to scale. We have established ways of storing vast amounts of methane, so we could build a stockpile big enough to provide power over extended periods of weak solar or wind generation.In the short term, establishing production plants with controllable demands, like aluminium plants, may be an effective way to absorb the surplus energy we see causing negative prices today, but it is just a short term solution. If renewable output keeps rising, we need effective large scale storage to use it effectively.

author: tszaboo
author_rank: Super Contributor
timestamp: January 09, 2020, 09:44:51 am
content: Quote from: ahbushnell on January 08, 2020, 11:21:45 pmI think right now they are at about 60% round trip efficient. But it doesn't really matter. Solar and wind is so cheap now, and it is getting cheaper every year. In a few years it could be cheaper to just build 2x the solar capacity then what you need, and use the excess in storage. When the price of electricity is negative, and you have to turn off your inverter, efficiency doesnt matter.The company I worked for did a study. We were gathering solar generation data, and using simple AI to analyse it. Turns out, 20% of Belgian home solar installations had to be switched off every now and then. What happens during the day, everyone goes to work, there is little electricity usage at home. Sun is shining, electricity is made. And the voltage increases on the grid. If you go above 240V (or something like that) then the inverter has to turn off. Of course you could install thicker cables, or use different ratio of the 10Kv/240V transformer, but that also costs money.And the P2G plant costs a lot now, because they are in research phase. CH4 is good, there is already infrastructure for it, unlike H2, so the total cost is lower. I mean, you could create P2G plants that are the size of two shipping container, one a tank full of CO2, the other electronics, that converts it to methane, and connect it to the city's gas and water pipelines.Cars can be converted to run on it. Possibilities are endless.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: January 09, 2020, 11:29:45 am
content: Quote from: NANDBlog on January 09, 2020, 09:44:51 amA UK pilot project is currently underway to use existing natural gas network to accept 20% hydrogen.https://hydeploy.co.uk/If the pilot (on a University campus) is sucessful, the second stage is to roll it out to 650 homes.It seems like there are a lot of very promising projects in the pipeline (excuse the pun!) for use of excess electrical energy to feed in to the gas system...https://sgn.co.uk/about-us/future-of-gas/hydrogen

author: coppice
author_rank: Super Contributor
timestamp: January 09, 2020, 12:46:54 pm
content: Quote from: DenzilPenberthy on January 09, 2020, 11:29:45 amThe UK gas network was originally built to carry a gas than was predominantly hydrogen - coal gas. It only started carrying natural gas in the 1960s, when gas from under the North Sea started coming ashore.Why would anyone use hydrogen in the natural gas network, when they can use natural gas? The efficiency of the CO2->CH4 process may not be fantastic right now, but neither is the generation of hydrogen. You can't mix too much hydrogen with natural gas, or all the gas appliances need to be changed, just as they needed to be changed to move from coal gas (lots of hydrogen and some methane) to natural gas (mostly methane) in the 1960s.