I'm a bit surprised that they are using Hydro power to handle the extra demand, given that natural gas turbines generally are easier to locate close to urban areas. However, their marginal costs are lower. I'm more surprised that this is done manually. In the US, or at least in New York State, this is a market system and scheduling is done by a big 'ol linear program. It takes the supply curves from power plants, the amount of energy required by each region, and the constraints imposed by the physical limits of power line capacity, and solves for the lowest overall cost required to power New York State.
To be more detailed:
For a given region, the algorithm schedules the lowest-cost sources first and keeps adding higher and higher cost sources until it reaches necessary generation capacity. Then, everyone is paid the same rate as the the marginal watt that just got scheduled. As a consequence, sources of power which cost money to shut down, like nuclear plans, will actually bid negative into the market to ensure they are scheduled. This is followed by low-marginal-cost plants like hydro dams. Then coal, which is relatively cheap. Then natural gas which is more expensive (or at least was before fracking) but the turbines for which can respond quickly. This actually happens twice as they run this market once the day before based on predictions and then run an adjustments market in real time. IT is actually possible to sell power in the day-ahead market and sell it in the real-time market without owning any generation capacity and do arbitrage. Another way to do arbitrage is to build two reservoirs and pump water to the higher one at night when power is cheap and then generate hydro power during the day when power is expensive [1]. You can also use flywheels or batteries. There are also markets for ancillary services like standing by ready to generate electricity or decrease generation with a few seconds' notice.
Thing with Britain is that pretty much everywhere is close to an urban area. The National Grid is truly that: national. Hydro comes online instantly, faster even than gas. It's perfect for these unique-to-Britain spikes.
The interesting parts of this video are the reasons why it's needed to be done manually: catering for spikes in demand which are easy for humans to predict, but very hard to provide for algorithmically. Commonly it's stuff where a significant chunk of the nation is watching the same program on TV. For example, half time in the FA Cup Final; the end of an important episode of a nationally-loved soap opera like Eastenders; the first commercial break in the new series of Downton Abbey, that sort of thing. On those occasions nearly everyone will go to their kitchens and switch on their electric kettles to make tea at the same time. The extra demand of 14 million one kilowatt kettles all going on at once is gigantic and instantaneous, and on a whole different timescale to the kind of day-by-day market pricing and scheduling you're talking about.
I don't think there's any equivalent in the USA at all. There's no spike in demand during the Superbowl half time, for example; the most you'd get is a little bump as everyone opened their fridge doors at once to get another beer. The only similar thing I can think of is the drop in gas pressure you get in a major city on Thanksgiving.
Not exactly the same - especially since water gets drawn out of reservoirs (typically) so there's already significant buffer, but here's a plot of water consumption in Edmonton during Canada's gold medal olympic hockey game back in 2010.
Water can be stored almost losslessly, with cheap fixed costs (e.g. the many cisterns in a household, e.g. the iconic watertank that appears in US movies). Transporting water long distances usually has large fixed costs, and has massive marginal costs if it has to go uphill.
Electricity is expensive to store, both marginal costs (losses) and fixed costs (plant). Pumping water into hydro-electric lakes is a reasonable solution at present but: 1. pumping has significant marginal losses, 2. usually lakes can't be placed near significant urban loads (desireble to reduce network failure risk, and optimise network loading), 3. hydro-electric lakes are often hard engineering (earthquake risks, difficult to get good potential energy storage if flat land), or politically difficult (consent, water rights), etc.
We need to invent better systems that can profitably sell peak load and buy off-peak load (or buy constant load). Especially for periods of a day or even longer. That would also solve a lot of issues with eco-friendly power (solar, wind). Especially that can absorb huge amounts of load (e.g. overnight). Especially that can absorb and release load within sub-minute periods. Big engineering :-)
This is why wind and solar are good partners with hydro. They're more unreliable due to weather but if you have the wind or sun available to generate more power than you need, you can use the excess power to pump water uphill into a hydro lake and store it for later. So even though it's a lossy operation as you say you're basically getting it for free. And like the video showed, hydro is very responsive to short term load demands so if the wind falls off you can quickly start up a hydro plant, as opposed to something like coal or gas which takes much more effort to start/stop.
Theoretically you can put wind/solar much closer to urban centres but in reality the NIMBYs don't want them either near cities where they can be seen or in remote areas which are typically areas of natural beauty.
I would guess due to a design flaw in the market rules (or the rules for the interaction between different national markets).
I think most large windmill turbines are designed to be able to be feathered to limit electricity production - they need some way to not fail when winds exceed generator constraints - but maybe designs use wind stalling or other dynamics to prevent that? Alternatively they could build dumping loads close to the wind power - e.g. warm some seawater with big resistors!
Edit: I love the quote "Wind farms in West Texas earlier this year were paying utilities to use their electricity on particularly gusty days because they can still earn $22 a megawatt-hour in federal tax credits." LOL.
Electrical cars with "smart" chargers. The chargers will have two settings. Express (high price, uninterrupted charging), and Economy (low price, maybe even free (fixed cost), charging controlled by the power grid, "full by the next morning").
This is has been the dream/vision of the power companies in Denmark for at least a decade. It is usually brought up when the government pressure them to generate more power from wind. Current level is 20%, goal is 50% by 2020.
Even 20% is more than is practical in isolation, but we export peak production to Germany, Norway, and Sweden. The two later have hydropower production (and no earthquakes), which can be lowered when cheap Danish excess wind power is available. Not sure that can be scaled to 50%, especially as Germany has similar plans.
I have read that electric cars will be the new "smart grid" connected appliances. Once say 50% of people have an electric car, which is probably usually left plugged in on the driveway, that's a huge amount of battery power available nationally, ready to be fed back into the grid as needed.
They are! They also cost a bloody fortune for a crappy model when you do manage to find one. None of that lovely British high-tech, insta-boil, sleekly designed space age stuff here: it's all vintage 1980 two-cup Travelodge hotel room specials. For $150.
When we moved to the USA my wife was furious with me for refusing to buy her an electric kettle. It took me months to explain that I'm not spending over $100 (plus the electricity to run it) when I already have a nice old fashioned stovetop model and the landlord pays our gas bill. Water still boils at 100 degrees, and it's just as fast on the burner. (She claimed it 'tasted different' but I didn't have the heart to point out that that was more due to the different water than changing how we applied heat to it.)
Depends on how efficient the heat transfer from the gas burner to the bottom of the kettle is...
I suspect that in the domestic setting an induction stove and kettle with appropriate base would be the most efficient.
I have both gas and an electric kettle (being British in the US) and the electric kettle is significantly faster for me (with similar amounts of water) but loses out because it takes up counter space, whereas the kettle on the stove is only a nuisance when cooking large meals...
I doubt it. Even if you had perfectly efficient electrical kettle, you're starting out at about 50% overall efficiency since a lot of energy was wasted creating the electricity from heat in the first place. This is why I limited my statement to electricity generated from fossil fuels, which does cover a lot of electricity.
I am more surprised they didn't mention load control i.e. turning off consumer or industrial loads.
If consumers use electric hot water cylinders or thermal storage heaters, then that uses a massive percentage of consumer power usage. It can be automatically reduced by using ripple control to turn off.
Perhaps they already have turned off those demands during peak base load evening hours? Or maybe that part is already automated and the person in the video is dealing with the excess usage above that? I think in the UK it is very common to use gas powered hot water, and boilers for central heating, so perhaps load control opportunity is not significant?
The existing system works perfectly, with very little increase in costs (the major engineering works were done years ago, Tea after TV has long been part of British life!), so there is no need for a compromise like load shedding.
Electricity networks are all about ensuring there are multiple independent ways to deal with uncommon problems, so that you don't get failures.
If you get an uncommonly dry season and the reservoirs are empty, then the BBC will be forced to stagger your coro, or more likely you will get in line at the post office and receive ration-books for your tea breaks ;-P
It hasn't happened in the past 30-40 years that this system has been running, about the only thing you can count on in those parts of the UK where the hydro is based is rain...! I think the investment needed for such a remote possibility isn't warranted, especially as water supplies dry up fairly slowly so there is at least some warning to start rationing the tea-bags. Coronation street is ITV by the way, the BBC will be staggering EastEnders. The best way forward is probably to axe such shows....(dreams of more room for better programmes on TV..)
Edit: just noticed polishaw saying UK had a 100 year drought in 2011. Also STOR and Triad mentioned above are load shedding. Following is musings, not facts :)
New Zealand has mostly reliable rain, but a few years back it had a national drought which caused noticable economic problems (Noted that the problem was due to lack of power and the forced changes to control power usage - not so much due to load management!).
If the UK had a drought, I suspect there would be a lack of hydro power, and that could easily have some interesting effects upon the network. Yes there is plenty of fore-warning, but that doesn't mean it wouldn't cause difficulties.
Also in New Zealand the constraints on hydro-electric have been slowly getting more restrictive over time due to eco-friendly rules (min and max outflow rates, min lake levels). And if the UK is anything like New Zealand, over decades the network load will increase but hydro-electric capacity will remain fairly static.
We did indeed have a drought in 2011, and there were no ill-effects on this system. That's the point. Water shortages in the UK tend to affect the southern end, and most of these hydro buffers are up north, where they wish it would stop raining.
Increasing loads on the system won't really effect this type of setup, hydro is used as a peak buffer not for base load, peaks like these will tend to have the same order of magnitude (they have over the past 40 years while base load has increased).
There are other issues with power in the UK, but dealing with post TV tea peaks isn't one of them, and isn't worth investment which could be spent better elsewhere on the grid.
The drought only really effected the south, the north and Scotland still had less water reserves than normal but plenty of capacity left. The hydro generation is mostly based in Scotland.
There is also a Welsh hydro-electric dam, excess capacity from the grid pumps the water up the mountain during the night and then it's released as and when.
The demand is increasing by 3 gigawatts in less than 5 minutes, right at the end of a popular TV show. The operator who oversees the whole grid has a TV to be able to watch the show, to know exactly when it ends and be prepared. That is insane.
The demand for the whole country is ~40 GW on average. That's an 8% increase in 5 min.
Right... and I thought that the story about the destruction of Melmac was crazy:
"In Pennsylvania 6-5000, Willie asked if the reason the planet was destroyed was nuclear holocaust, but ALF claimed it was because every Melmacian plugged their hairdryers in at the same time. If this theory is true, it must be that the power system of Melmac is linked directly into the core & the energy surge would cause the planet to detonate."
actually, what strikes me as insane in that summary is that the end of a popular TV show might not occur at a fully predictable time. Barring preemption, I think of TV shows as occuring with clocklike regularity, and even with preemption, it's more common for the interrupted show to make like nothing happened and just air the parts that would have been showing then anyway, than to air over an altered time period. Is british TV so different? Why does the operator need a TV to know when a show will end?
The best example is sporting events. I mentioned half time in the Cup Final in another comment: there's a referee-determined amount of injury time added to each half of the game, then that is subject to the ref (who is, as is required by the job, blind) bothering to check his watch. It's impossible to point to a given five minute window when the game will end.
And yes, British TV is pretty different, at least on the main channels. Over-running programmes will push everything else out to start later, rather than simply starting five minutes in.
TV shows - even in the USA - start all over the place, they are absolutely not 'clocklike' at all. So bad even TiVo has a hard time getting it right.
I think that's partially due to the fact that syndication, national providers selling programs to local affiliates is a larger thing here in the States. Those programs go out at a specific time and often the local stations are just relays and can't time shift things.
Contrasted against the system in the UK with the BBC where there's not really a local affiliate but a national station. In that case it seems much easier to shift for longer running programs.
Both the BBC and ITV are regional, with a core national schedule but lots of opt-outs. Most news broadcasts will be followed by a regional news programme. BBC Scotland, Wales and Northern Ireland regularly opt-out of the main schedule to show locally-produced programmes.
"EastEnders" is the most-followed national soap-opera (rivalled only by "Coronation Street"(aka "Corrie"), but that's not on BBC and has a more Northern focus, so I guess Corrie's kettles are less powerful? Who knows). It's aired twice every day except Sunday (when they air all episodes for the whole week in one go). Like every soap, it will end every episode with a carefully-timed emotional cliffhanger. Episodes are filmed well in advance, but edited fairly close to the actual airing date, to avoid too many plot-leaks. Hence, episodes can be slightly longer or slightly shorter, and they usually make up for it by cutting the credits reel (which starts with the famous "tum-tum-tututum" sound you hear in the video); nobody cares about that, of course, so I guess programmers are just guaranteed "at this time there will be credits", which is not enough for the "electricity watcher" because people will fire up their kettles as soon as credits roll.
Cutting short actual EastEnders footage to accomodate some abstract timing issue would result in a lot of angry calls to the BBC!
Also BBC does not have ad breaks so if it is a popular program all the tea making demand takes place at once unlike the more commercial channels which have 4-5 ad breaks per hour.
My guess is that Corrie's kettle effect is similarly powerful, but since it's not a BBC series the BBC chose not to feature it in their documentary...
I'm also a little bit cynical about how the show presented the failure of the French interconnector - I'm inclined to assume that the documentary producers egged up the seriousness of the situation a little bit in order to provide the obligatory reality-TV deadline-drama.
They actually cover this in the video. The operator is given a time when the show is ending but the time is actually incorrect so he has to watch the TV for instances like that.
Perhaps he wants to know when most people will leave? While a show might end at the hour mark, the important bits will end at different locations near the hour mark, and he might need to judge when viewers would be most likely to stop watching?
That doesn't happen in Greece. Shows usually air within five minutes of their specified time, but it's not clock-like by any stretch.
One show, in particular, regularly airs 40 minutes after its specified time. I find countries with TV shows that air exactly when they're supposed to to be almost magical.
Here in Brazil, where Globo is like BBC for its power and popularity we have 3 soap operas at night, the 6-oclock Soap Opera (Novela das 6), the 7-oclock Soap Opera (Novela das 7) and the the 8-oclock Soap Opera (Novela das 8). But in fact, the novela das 8 starts at 9:00 at least. And we have another thing, in the regular season of football, in wednesday start at 9:45, so the soap opera has less time to run.
In Brazil, you can never trust the time of the programmes, when the networks make ads of it's shows they announce not the time, but the show that was before. Like "Watch Avenida Brasil just after the Jornal Nacional".
In France, Italy, Spain and Portugal, shows air usually very timely... These are the countries Greece is usually compared to. Commercials in Spain and France (that I know of) are heavily regulated and monitored.
This has made me think about what happens here in Germany: All the main TV channels start their big show of the night at 20:15 (but I guess due to competition for viewers sometimes a channel will start their show one or two minutes earlier).
Then the main channels will often have ad breaks at the same time (I guess so they don't lose viewers zapping to other programs). This seems like a bad idea given Germany's push for green energy production, but I wonder how could the government or the energy producers persuade the TV companies to spread out their ad breaks?
The problem is not with timing of shows, but with the British obsession with tea combined with the credits of a very popular show. In a million homes there are people (2.4 million?) who are suffering tea withdrawal symptoms and they all turn their kettles on at almost the exact same time.
The Germans I know would probably just get a beer or open a bottle of red wine.
20 years ago in Australia, there used to be a comedy show on the government TV channel (no ads) called the Big Gig. It was a live show, but people claimed it was pre-recorded. So one of the hosts had a TV to show what was on the commercial channels to prove that they were live. Didn't quite work as planned - each of the other channels had advertisments running at the time :)
I have lived in France for 24 years, and TV shows were (in the 1990s and 2000s - not sure these days) routinely late or early by ~5 minutes or more with respect to their planned time. I totally understand why the operator needs to watch live TV to know when the show ends, given that the window of power surge is only 5 min.
I don't think it really bothers anyone here, so they haven't really tried to change it. We have a lot of live shows on all timeslots (morning, mid-day, afternoon, and night), so if each one overruns by a bit, another one must compensate. I think that might be (part of) the reason.
You can actually view electricity production on an hour by hour basis in Ontario. After a big game finishes in Ontario, there is generally a spike in the production of electricity.
It begs the question why can't the operator watch a computer that does the operator's job for him. Is split second power allocation really done better by a human? Note I'm not suggesting computers are perfect operators, just less error prone.
This is exactly what i was thinking, even though the finish time of Eastenders might not be what the BBC says it is, its not like it would be hard to write a program to listen for the "Dun, dun dundundunduuun" and turn up the power.
The good thing about humans is they have very well-written exception handlers built in!
Such a program is likely to be brittle and could fail unexpectedly requiring human intervention. There are also many other events that couldn't be triggered, such as the beginning of commercials for non-BBC shows, the beginning and end of popular sporting or other TV events that would trigger the same phenomenon. It's probably far simpler and cheaper to have someone sit there and press buttons, with the added bonus of high accuracy.
I don't know. I haven't heard of any major outages as a result of this guy not doing his job properly, and if it's just the one guy... why replace him with software? It doesn't seem worth it.
Well i'm a typical software geek, if i see something that can be automated, i cant help but think of a way to do it, not saying that everything should be, but it almost always crosses my mind.
Given the level of care required in writing software for running the national electrical grid, I think it's quite likely that writing the automation software would be more expensive than paying a human to deal with it. (Especially since this is just a small part of his day -- he presumably has other responsibilities as well.)
Emphasis should be on often. I don't think a cost benefit analysis would show automation in this instance to be worthwhile. But it would be interesting to see if I'm right!
I would assume that the National Grid have done such an analysis and determined that it isn't worthwhile, seeing as how... they still employ a bloke to do the job!
I'm pretty cynical... I suspect the analysis was - do we allow the guy on duty watch East Enders and do his job after hours, and pay him a bit of overtime, or do we pend a lot of money for IT to come up with an automated solution that might not work th first time...
There is already an impressive amount of work put towards the software monitoring the whole grid, as well as its frequency. I don't think engineering is the problem.
It's not just "turn those and those supplies on when the show ends" but actually managing the best possible supplies and possible exceptions. Plus, the show ending is a very visual example, but I'm sure not always (and not everything) is up to EastEnders credits rolling.
If humans end up creating an army of robots that genuinely are better than humans in every conceivable way, why /should/ we continue to exist? (Other than how humans currently allow animals "lower" than ourselves to exist, ie for food and entertainment)
Remember that determining when something on TV ends is not that simple. Most will leave when the credits show. And for football when people leave could actually depend on which teams play and which team wins. E.g. if England wins I bet the spike will be delayed. Teaching an AI this seems unnecessary compared to just having a human do this.
Fine, that solves the problem for exactly one ephemeral correlate of power consumption surges. What about the next one?
If we're talking armchair first-stabs at automation, I'd much rather have 1) a large set of historical data from distributed consumption data feeds across the service area and 2) analysis of that same data live and with near-realtime latency. Given that, it seems plausible that a well-chosen machine learning based system could provide useful automated assistance.
That said, there are a bunch of practical reasons why it probably never makes sense to take human judgement out of the equation, esp. given the potential infrastructure impact here.
An explicit signaling solution seems more appropriate here. Suppose the BBC were to embed a frame containing a time-remaining flag at various points in the broadcast. Then the power guys could write some software to watch the stream for these frames, decode them, and estimate the spike.
If necessary, legislate the presence of the frame.
That's why we don't let politicians design technical systems. They're bound to come up with solutions that sound good but that will not work in practice.
Some problems with your approach:
- partial loss of signal -> false positive -> power surge
- loss of signal -> false negative -> grid overload
- how do you signal the need for a little bit more power?
And so on.
The British solution is typical: it's simple, and it 'just works', the speed with which hydro comes online it is just not enough to be reactive but even a little bit of forewarning and they'll be fine. Heck if the TV fails he can call home to mum, or some other place.
Solution of last resort: a slight brown out due to lack of information, but as long as this system has been in place you'd think if that were a statistically frequent thing that it would have happened by now.
Compare it with the auto-traffic-info system present in most car radios.
The alternative frequencies system works along the lines you suggest (though technically it's not a 'frame' but an entire channel with its own carrier wave). This fails so frequently that I usually disable it. Either you get switched to some totally unrelated station (without traffic info to boot) and then never switched back or you're listening to a CD or so and then you'll suddenly be in the midst of some radio broadcast and again, you're never switched back.
Easy to propose, using an unreliable medium such as a TV or radio channel apparently very hard to get 100% right.
And if you're going to change major parameters in the electricity generation capacity of a nationwide grid I assume you'd put the bar for reliability a bit higher than I do for my car radio.
This system is fairly poor in the UK. It has an ostensibly useful feature whereby local radio stations transmit a flag to say they're currently broadcasting traffic information. This then instructs car radios to interrupt what the listener can currently hear (eg. a CD, a national broadcast) and play the traffic bulletin from the local station. Sounds useful.
In practice, FM radio signals travel so haphazardly that in most areas, you're likely to be interrupted several times an hour with travel news for towns and cities 40, 50, 60 miles away. I regularly get the bulletins for places as far afield as Shropshire, Humberside, Merseyside and Lincolnshire. If, while driving, the signal becomes too weak for the 'traffic off' flag to be received, the radio will simply stay tuned to the FM frequency until the listener manually cancels it.
In addition to this, illegal 'pirate' radio stations have started to take advantage of this feature - some of these transmitters have the traffic flag set to 'on' constantly, with the obvious effect of switching listeners' radios to the illegal station regularly.
Ah, yeah, I think you're slightly misunderstanding this proposal.
First, and the biggie, the BBC would be responsible for including Cue Dots/Marks/Frames which signal the program's TTL not that "more power is needed in UK". That'd be irrational and dangerous. It's up to the power guys to interrogate the cue information and then react to it. That's just basic separation of responsibilities.
Second, you'd still want a centralized component to interrogate the cue information and then tell power utilities to turn on/off, just like the current model. Of course, they will still need people in the loop - the computer would be there to propose which assets to activate and to provide a countdown to when a decision will need to be made - a guided decision making system. (Computers can do this sort of cost optimization faster then people.)
Third, their man in the power HQ is already relying on a TV set to predict when the spike is about to occur, so any sort of system has to be at least that reliable (i.e. not very).
Fourth, what if the power boffins lose the signal to the BBC? Calling "mum" is a terrible idea, but having automatic failover and/or redundant reporting stations are the type of precautions a basic safety review should uncover.
TLDR: Not suggesting that the BBC tell the Power Co that they should add more power to the grid. Just suggesting a system to augment decision making based on Program TTL.
That's probably too brittle a solution. Eastenders ads, other programs etc. could conceivably play enough of the Eastenders theme tune to trigger unnecessary power surges.
Well it was a half sarcastic comment but theoretically you'd only have to have it active when the program is live, i'm sure theres some kind of computer system at the BBC that tells you whats on air at the time even if its unscheduled.
And then EastEnders changes the tune ever-so-slightly (without notifying National Grid operators, of course), and the program breaks. Or the soap gets moved, or cancelled, and the program breaks.
1. if a statement or situation begs the question, it causes you to ask a particular question It's all very well talking about extra staff but it rather begs the question of how we're going to pay for them.
As a philosophical term of art, 'Begging the question' is a logical fallacy whereby the conclusion of an argument is just the restatement of the premise(s).
Commonly however, it is used to mean 'raises or leads the question'.
Whether the common usage is correct or not depends on which side of the descriptive/prescriptive language fence one sits on. (A matter totally off topic)
I am aware of its philosophical meaning. But normally one does not correct someone's usage of a word if that usage is in the dictionary, even if it might not have been fifty years ago, except if the topic under discussion is philosophy or logic.
Yes, but that's not what the phrase originally meant. Its usage has changed over the years to the point where things like your source consider the new version to be accurate.
However, there are many - including myself for a time - who still fight to preserve the original meaning. I stopped doing it when I realized that a) English is a fluid language, and b) some people - again, possibly including myself - simply liked to correct people to show off.
I hate this trivially predictable response. Similar to observations of Betteridge's Law of headlines, "begs the question" corrections just seem like HN karma pumps.
Notably, it does not mean what the logical grouping of those words would mean: "begs for the question to be asked".
Of course, I believe I've seen "begs the question" used correctly exactly never, and there's an obvious need for a pithy idiom for "begs for the question to be asked", but we don't really have one.
This once again awakens my suspicions that the English language is an elaborate practical joke. And I say that as a native speaker.
The misuse of "irony" is another one of those situations that seems to show that there's a missing word in the English language.
To take one specific example from Alanis, (yes I'm going there), there's something peculiarly funny about "ten thousand spoons when all you need is a knife" in a way that wouldn't be if you had "ten thousand turtles when all you need is a knife". I think we needed a word for "bittersweet happenstance", and people wrongly latched onto "irony".
Which is presumably where the confusion with irony (as a stand-alone word) comes from.
Interestingly enough, the term exists in a literal translation in other languages, too: "Ironie des Schicksals" in German, "ironie du sort" in French, and "ironia della sorte" in Italian.
It's just a way of filling time and distancing yourself from the question. Irregardless of pendantry about the definition you usually improve your sentence by just leaving it out.
If you're paying for an operator anyway, you may as well get him to do the job rather than spend all that money on a computer and have the operator watch the computer. The operator is likely to need rotating in a watching job like that too, further increasing costs (I believe CCTV operators need to be rotated every 20 minutes, but that may be misremembering).
Unless you're suggesting that people can trust the computer to do it unobserved then there is little value in having the computer there. Which is a case, I might agree with. My first thought is I would absolutely love to have that job. I'd pay to have that job. Then I could optimise the hell out of it.
Can you take a computer to court if something goes wrong? The British tabloids need some one to blame, and a computer isn't that photogenic. It has to be a human scape goat.
I don't know enough about the English power market to draw comparisons, but I'll outline a little bit about how the Australian NEM (National Energy Market) works and how it deals with situations like this. My understanding is derived primarily from an old house mate who did his electrical engineering honours around the NEM.
A while back the various disparate energy grids in Australia were more-or-less unified into one big grid (well, a few small grids with intercouples), the NEM was established, and the newly formed company NEMCO tasked to govern it.
The NEM is a bidding market, where various energy providers (and interestingly consumers, more on this later) provide bids detailing how much energy they are willing to provide and at what cost. These bids are placed, I believe, at least one day in advance though they can be revised after being placed.
If a providers bid is successful, its output gets adjusted automatically by the NEM to fulfil the quota allocated to it (note: "NEM" is used to describe both the market and the computer system that manages it, as far as I can tell). The providers will be paid whatever the current 'spot-price' is, regardless of the original bid price.
The spot-price is determined by, essentially, greedily consuming the cheapest energy possible until demand is met. Demand is met when the frequency lies within an acceptable bracket (around 50Hz). So a coal power station with high base-load capacity will place low bids for the majority of its capacity, to ensure that it gets picked first when demand is being met. It costs a lot of money to turn a station like that off, so they price their bids accordingly. Gas turbine engines have extremely low start and stop costs but their operating costs are significantly higher. These turbines will price themselves so that they get turned on only when demand is high and the spot-price has increased accordingly.
During some heatwaves in the summer the spot-price can increase to thousands of dollars per megawatt/hour and it is extremely profitable to have a diesel generator hooked up to the grid to take advantage of precisely these situations.
I mentioned before that some consumers will place bids. The realities of power generation mean that a station shutting down can be a long and expensive process. They need to ensure that someone is buying their electricity so that that doesn't happen. Typically this comes in the form of a brokered agreement with a large consumer, such as an aluminium smelter. The smelter agrees to buy a large amount of energy at a certain price (the details are a bit fuzzy to me) and the station ensures that they never drop below minimum load. The thing is, there is a point where the difference between the spot-price on the market and the brokered purchase price is larger than the value of the aluminium that can be smelted with that energy. When this happens, the smelter shuts down its smelting operations and sells the energy back to the market instead.
Now its not so simple as the greedy algorithm I outlined before, for precisely the same reasons as brokered deals happen - physical and political constraints. It's an incredibly complex job to schedule power station ramp-ups and ramp-downs while still balancing the load, but for the most part it's handled by the NEM. It takes into account renewable energy quotas (what my house mates thesis was on), maintenance shut-downs, water supply (for hydro stations) and much more.
One thing in particular that I found interesting was the cost of transporting the energy. There might be tariffs on intercouples between states, but the main cost is actually the distance the energy has to travel. You can't simply turn a coal power station up when a town in the middle of the desert has a power spike, as the attenuation between those two points (well, the closest station that has excess capacity as a result of the increase) means the demand isn't met. Instead, a diesel generator near the town might need to be turned on, which can be very expensive. The grid has a number of way to mitigate issues like this, but it's still very interesting.
The point is, a well written system makes this market work efficiently, but the domain of the problem is still huge. The (mostly) free market takes care of many of the load balancing issues, however human intervention seems unavoidable because there are simply so many things that can go wrong.
[Edit]
NEMCO is now called the Australian Energy Market Operator (AEMO) and their website is at [0]. It has lots of good stuff to look at for the interested. In particular [1] has lots of nice details about the history and structure of the Australian Energy Markets.
Most electricity markets are highly regulated markets, and the regulations are enforced. You are "free" to trade if you follow the rules.
Read some of the PDFs for http://www.google.com/search?q=electricity+market+design
and you can see some of the issues and some of the suggested solutions. Market rules are designed to create a functioning market - like a system architecture - to achieve network reliability, price stability, reduce political interference, and prevent gaming the system (Enron, but gaming can happen anywhere in the system).
Physical electricity connections for consumers are often natural monopolies, and thus require regulation. Imagine you could only buy power from an unregulated AT&T and that there was only one AT&T :-)
It is a very specialised job to design the rules and enforcement systems for a market so that the players (independent suppliers, consumers, and network operators) have the correct incentives to acheive systematic goals.
When the regulations fail, you get Enron and Southern California. When the market rules are not designed correctly, Iraq consumers have blackouts even though their next door neighbour has power to spare, because there is no incentive to build or run a transmission connection between them (e.g. due to fuel subsidies, or political instability). When contracts or the free-market fails, they cause Germany to dump excess wind turbine power to a buyer in another country, but they overload the network of a third party country stuck in-between the generator and load. Regulations are set up to help prevent the whole US eastern seaboard blacking out due to domino effects of network failures and individual incentives of the players to avoid costly redundancy or over-capacity.
99.9xx Reliability costs huge money, and rules help incetivise players to be capable of handling black swan events. Most consumers care about reliability, but most are too small to have any purchase power to effectively influence power producers/network operators (networks have monopolies on connections to consumers, only a very limited number of huge consumers have independent connections).
Deeply hard problems: political, economic, and technical.
700 million people blackout! Long article, but not very technical, contains some excellent quotes and sound like free anarchy at individual, corporate and government levels - corruption, politics, theft, fraud, overload, fatalaties.
I liked this quote: "No one is taking care of the grid — the network of transmission lines, interconnectors and transformers that is essential to life as we know it; two, supply cannot keep up with demand; and three, rate-setting is a political rather than an economic process. It should not come as a shock, so to speak, that neglect, failure to prepare and playing politics with essentials should lead to disaster ... No less than the American Society of Civil Engineers said in a report released in April that the [US] grid could break down by 2020 unless investment in it is increased immediately by about one billion dollars a year. Why so much? Because, according to the report, more than two-thirds of the system’s transmission lines and power transformers are at least 25 years old, and 60 percent of the circuit breakers have been in use for more than 30 years."
Here are some of my favorite quotes:
..."At 13:30 EDT, the MISO EMS engineer went to lunch. However, he forgot to re-engage the automatic periodic trigger."
..."Also at 15:42 EDT, the Perry plant operator called back with more evidence of problems. “I’m still getting a lot of voltage spikes and swings on the generator . . . . I don’t know how much longer
we’re going to survive.”
..."At 15:46 EDT the Perry plant operator called the FE control room a third time to say that the unit was close to tripping off: “It’s not looking good . . . .We ain’t going to be here much longer and you’re
going to have a bigger problem.”
A great read both for its tutorial and historical value.
> "So a coal power station with high base-load capacity will place low bids for the majority of its capacity, to ensure that it gets picked first when demand is being met. It costs a lot of money to turn a station like that off, so they price their bids accordingly"
Nuclear puts in bids of zero since adjusting the power output of those is difficult. Coal is quite flexible once the turbines are running so can be used to deal with upcoming demand (ie if you realise that you need more generation in 30mins time) - apparently this is because they run most efficiently at 70% of max output. Gas generation/stations are most efficient at 90-something-percent of max output, so they have less short-term flexibility than coal. Hydroelectric storage is the quickest to respond but also the most expensive (generation within minutes - some folks I knew called it the 'emergency button' :).
That's all random stuff I learnt years ago over a summer in the industry.
This is very interesting. I can add to this that the NSW and Victorian governments passed some legislation that all retailers of electricity must offer a percentage of power used be fed into the grid through renewable sources.
Some people go for 100% renewables - this means that if they consume 3Mw power then 3Mw power will be guaranteed to be generated from renewable sources. Would love to know how they calculate this.
The kicker is that they pay for the privilege of using renewable energy, yet they still have to pay a carbon price on their power.
My understanding is that the Renewable Energy Target is actually set by the Commonwealth. Though since it's not really something directly under any S.51 heading I imagine they do it by paying the States and then the States pass the laws to make it work. [1]
I too find it weird that the RET stayed after the introduction of the carbon tax. The entire point of putting a price on emissions is to allow the market to sort out the most efficient way to abate them.
Buuuut of course the RET was started by Howard et al to prop up sugar cane farmers and now it's propping up Gillard's mob in the Parliament. So for now it's unkillable.
[1] On the other hand, when has the concept of limited heads of power ever stopped the High Court from giving the Commonwealth what it wants? I guess they could shove it under 51(i) (interstate commerce) or 51(xx) (the corporations power).
They work out how much renewable generated energy they're obligated to provide (or estimate) and ensure that they have at least that much renewable energy generation capacity. The actual electricity supplied to the households doesn't have to be generated from renewable sources.
The current (conservative) government in Victoria is no friend to renewables. It's brought in rules saying that anyone within 2km of a proposed wind generator has total veto rights, regardless of whether they can see or hear it from their property. There are also six areas in the state where wind generators are simply not allowed, period - most are around coal stations.
I used to work for a company where the owner was also involved in the wind power industry, and every now and then we'd hear things like the above. It ain't exactly being encouraged by our state government, that's for sure.
In the UK, I believe that the electricity companies have to provide a certain percentage of renewable, but electricity paid for by people who want "100% renewable" counts towards that target so people are paying the electricity company to do what it was mandated to do anyway. It's not like the electrons coming into your house are in any way connected with a specific type of provision anyway.
>The thing is, there is a point where the difference between the spot-price on the market and the brokered purchase price is larger than the value of the aluminium that can be smelted with that energy. When this happens, the smelter shuts down its smelting operations and sells the energy back to the market instead.
That seems odd, Aluminum smelters are even harder than coal fired power stations to power cycle. The cells have to kept constantly molten, freezing damages them.
Pot-lines can be turned off for periods of seconds to hours because they have plenty of thermal inertia (assuming the control systems are modern enough, and the power regulations make it profitable for the smelter to do so).
They can also temporarily shift taps (change voltage and power draw) to increase or decrease load, within some constraints.
Only if the pot is turned off long enough to solidify is it a problem - and even in that case if base load prices shift enough it can be profitable to do so in a functioning electricity market, e.g. for a pot cathode that is nearing replacement time they could turn it off earlier than otherwise. In New Zealand they once turned off a whole Aluminium smelter for months when we had a long dry spell and the country ran out of hydro-power (I recall the frozen pots had a > 50% possibility of getting restarted too - the chemistry is somewhat of an art so some luck involved!).
I have two friends who work architecting whole electricity markets (for a whole countries). They have masters degrees in operations research. Pretty cool designing how to set up the pricing, bidding, and rules to optimise for changes base load, spot load, failures, network limits, etc etc. It is hard to design bidding systems to avoid market failures - think Enron & California!!!
If you ever get a chance to visit a smelter, do it, they are damn cool engineering. High current at low voltage (the pots are like huge molten batteries) and the bus-bars cause very large magnetic fields and are apparently dangerous if you were to carry a magnetic tool! IAAEE - I am an electronic engineer - even though I do full-time JavaScript development ;-(
Also a smelter essentialy only has two variables that control its profitability - the price of electricity and the price of aluminium. A smelter wants to have a long term futures contract for electricity supply, and matching long term futures contracts for selling aluminium on the commodities market.
They have some control over the price of electricity - the control is via:
* long term electricity supply options (e.g. the New Zealand government gave a smelter here a special decades long contract, so a company would set up a smelter in NZ, even though the bauxite is mined in Australia and shipped thousands of kms).
* possibly owning their own generation capacity (the NZ smelter had a large hydro dam built for it, and they had contractual control over its power).
* most importantly to optimise where to put the smelter to best take advantage of long term cheap power (cheap base load prices, supply reliability, political stability).
Shipping bauxite to NZ from AU is not far. Lots of bauxite is shipped from Australia to Norway to be smelted. Because NO has cheap hydro power, this is considered economical!
Interesting, I guess on those time-scales it does make sense. I was Qatar a few years ago when a series of power failures caused all the pot-lines on Qatalum's brand new smelter project to freeze.
My understanding is somewhat limited, as that is a second-hand anecdote.
They probably don't turn the smelters off completely, instead simply scaling production down to a minimum. This seems like the most reasonable action in any case, as they would want to continue smelting as soon as the spot-price dropped.
For me the most interesting part of this was the fact that energy brokers existed (not that surprising) and that the free market allowed for instruments like this to be developed.
There are quite a few levels of distribution as well, and each of those implement different market instruments to optimise for reduced risk and costs.
A hard problem that is starting to emerge is actually based on both how distributors amortise risk, and the emergence of smart meters.
Smart meters should be able to help regulate the entire market, because they give us better control over the load profile. The thing is, a typical consumer buys their energy from a retailer, who themselves will have agreements with wholesalers, who in turn work with energy providers and the NEM. Who should have control over the smart meter, its data and operation? Who should benefit from the cost savings and reduced risks?
At the moment the cost savings seem to be shared fairly equally, but ownership of data and control varies based on legislation (state to state in Australia). There is definitely a lot of room for innovation in this space; I'm looking forward to seeing how things progress as more and more of these devices are deployed.
The UK used to have that kind of system (from about 1990 to 2001). Since that time a more complicated system has operated known as NETA[0].
In the current system, generators and consumers (domestic supplier companies are "consumers") trade freely with each other but have to submit notifications to the system operator of the trades that they have done. You trade electricity in half-hours but 1 hour before each half-hour in question you must submit your final notification of your traded position. This profile is what the operator expects you to product/consume over that half hour.
You may also participate in the balancing mechanism[1]. This is where you also submit bids/offers to produce/consume more/less during that half hour. The National Grid will accept bids/offers in order to balance what it sees at the difference between your traded position and forecast demand. If you get your traded position wrong, the grid will have to balance things up by accepting bids/offers and the cost of doing so will fall to you (plus a bit more to teach you a lesson).
The Balancing Mechanism works on a minute to minute type level, to handle second by second fluctuations there is also a service known as Frequency Response which the more flexible generators may provide to the grid. This is a mostly automated system in which their generation equipment continually adjusts to compensate for the changes in frequency.
In the film we saw, at least one Hyro plant was ready to come on. We're not told whether it had sold its power on the open market or had had a bid accepted on the Balancing Mechanism. However, when the French inter-connector trips the Grid brought on another hydro plant. This would probably have been via the Balancing Mechanism. The operators of the inter-connector would have had to pay for failing to meet their traded position.
I worked in Western Power (Western Australia's distribution power utility) for a short while.
The thing with the smelting plants is that they are usually located far away from population centres, and close to a port (or they have their own port!). This doesn't help with the situation, as they are usually quite a long way from the generation plant. But it usually means they have a very substantial connection to the grid.
I'd love to go back there and learn more about this stuff. Power engineering is fascinating.
The corresponding graph is very interesting as well [0].
Demand rose steadily from 4:30am through to its peak at 4:30pm. Just after this the spot-price jumped from ~$100 where it had been fairly steadily throughout the day to ~$2300. The market quickly corrected itself, but that half an hour would have been expensive.
Assuming an average price of $2350 per unit, for 2800 units, that half an hour would have cost around $3.43M. In all likelihood the market would have corrected much more quickly than that, but even at half that price it is still a lot of money.
[Edit]
The market is actually calculated in 5 minute intervals, and this graph [1] shows it broken down like that. From it we can see that for 5 minutes the load was at 3050 units, and the price was $12750. The price is an hourly rate, so if this had continued for the hour it would have cost $38.9M. As it was for only 5 minutes, it was actually 'only' $3.24M
Looking at the half-hour averages, this seems to match up, so maybe we were fairly close to begin with.
1,500 miles of high voltage transmission lines would cost a lot ($billions). Much more than the economic benefit of sharing power resources across the distinct markets.
AEMO's National Transmission Network Development Plan [0] describes in great detail how they foresee investments in the (eastern) grid infrastructure. As a frame of reference, just upgrading a couple transformers to increase the transfer capacity between South Australia and Victoria will cost tens of millions.[1]
Stepping down from aluminum smelter load levels, consider the comparatively low power demands (orders of magnitude less) of modern lighting and electronics. There's some interesting geekiness to be found in their power demand under varying line voltage.
Voltage-regulated "inverter technology" electronics can, ironically, behave less "linearly" under adverse supply voltage conditions than resistive loads such as incandescent lighting and electric kettles.
Electronically-ballasted fluorescent lighting, CFLs, computer power supplies, VFD motor drives, "inverter technology" microwave ovens all electronically regulate their current draw inversely against voltage supply changes. Voltage goes down, current draw goes up, power demand remains ~relatively~ constant.
So when a brownout (voltage sag, not an outage) comes along, to some extent, these "well regulated" devices hide it from the user. You might not see a "brownout": The electronically ballasted fluorescent lights don't dim so much -- or at all --, your laptop computer keeps running fine if the sag doesn't drop too much, and any DC-powered fans won't necessarily slow down so much or at all. But maybe you heard a universal motor somewhere slowed down. Or maybe the lit-up display area on your old CRT monitor (is anyone still using those anymore?) shrinks 10% then comes back. You hear your computer's desk-side UPS click in (if it has a relay, cheap ones do) then back out but don't see the lights dim. I've seen and heard this and found it rather jarring.
The term "brownout" may become an anachronism (perhaps it has already), not because brownouts don't happen anymore, but because they don't dim the room lights anymore.
To see how much variation a small "non-dimmable" CFL will tolerate, I just put one on a variable transformer and lowered the line voltage gradually from normal (120 Volts) downward. Here's what happened:
o It lost very little brightness until about 60-some Volts
o Below that threshold, it just turned itself off
As a device user, this is what I'd expect of a "well-regulated" device that runs on mains (grid) power.
But I don't imagine such "well regulated" loads make grid dynamics marginally easier to control under the severe conditions which lead to voltage sags. Probably not much worse though, considering all the heavier loads a grid must support.
I wonder if this is offset by industrial loads that are integrated into the network to drop their loads within milliseconds or short timeframes? Large server farms that do offline processing can instantly turn off large loads without problem e.g. Youtube background video processing.
India has perverse loads too: "Microtek, an Indian company that specializes in selling power backup inverters, claims to have 100 million satisfied customers.". I have read of the same thing happening on water networks, where individual households connect pumps to the the public water supply to suck water when pressure drops too low (supplier can then only restrict rate rather than control pressure, and customers at end of line go without!).
Many Inverter loads have a bigger problem in that they often only suck current at the peak and nadir of each voltage swing (Volts), leading to an ugly non-sinusoidal current waveform (Amps) with odd or even harmonics. Networks add large expensive HV equipment to reduce harmonics. Networks also charge large industrial users more if they have bad current waveforms (either harmonics, noise, or power factor).
The opposite effect happens once a year in Australia, when factories across the country down tools for 10 minutes to watch a horse race, resulting in a large drop in aggregate demand over a short time period.
Almost universally electric. Remember that (being essential for tea) they may be used many times a day and be found in offices and other places without other cooking facilities.
Unfortunately, you can't make tea correctly with moderately hot water like what you get from some water coolers. The tea won't steep correctly.
Depends on the kind of tea. For black tea, near boiling is good, but for whites and oolongs it's not. Though I suppose the British are famous for black tea.
(I got a electric tea kettle with a built in thermometer not too long ago, so this is an interesting issue for me.)
Depends on the kind of tea. For black tea, near boiling is good, but for whites and oolongs it's not. Though I suppose the British are famous for black tea.
In the UK (& Ireland) "tea" means black tea. You can get fancy teas, but "tea" on it's own just means black tea.
We tried washing our hands with it instead, but that worked out even more poorly. :P Don't worry, the milk (and quite possibly sugar) kills the taste of the black tea nicely.
Well, British Tanks have a tea brewing device [1]:
"Similar to every British tank since the Centurion, and most other British AFVs, Challenger 2 contains a boiling vessel (BV)[citation needed] also known as a kettle or bivvie for water which can be used to brew tea, produce other hot beverages and heat boil-in-the-bag meals contained in ration packs.[9] This BV requirement is general for armoured vehicles of the British Armed Forces, and is unique to the armed forces of the UK."
They would always use electric kettles. The idea of putting (basically) a pot on a stove to boil water sounds like still going outside to an outhouse to go to the toilet.
When renting a house for a holiday in USA once, my family went out to buy an electric kettle to make tea & coffee, and they weren't as common in shops as we thought. That was a weird eye-opener.
We almost universally use electric kettles - to us they are regular kettles.
The US/UK difference is mostly due to the electric supply I think. At 230v with a max draw of 13Amps per socket UK electric kettles boil fast compared to US ones in my experience.
Canadian tea drinker checking in. I've used an electric kettle all my life and don't see what the problem is...
Electric kettles are common here even though we use 110V power. I've never timed it, but I think they can bring cold water to a boil in maybe 3 minutes, which is okay with me.
If electric kettles are rare in the States then I think it's because of a cultural difference, not because of the mains voltage. Sure it would be convenient if kettles boiled faster, but I don't think it makes that much of a difference.
Simply a question of available power. Typical British kettles use 3kW (comfortably doable with 240V@13A); under US power (110V@15A) you can only manage about half that, which means waiting twice as long for your kettle to boil.
(American here) I recently upgraded from a 1kW to a 1.75kW kettle and thought it was a huge improvement. It does trip the circuit breaker if I try to run the toaster at the same time as the kettle though.
Oh, I thought US circuits would be spec'ed at higher amperages to make up for the lower voltage. How does that work for high power appliances then? I have a 10kW induction stove, how could you ever get that kind of power from an installation running at 110V?
Some people put a cordless electrical kettle on a gas stove, and melt the bottom and damage the kettle. Seriously, I've seen this happen a number of times, I've almost done it myself.
Some are mostly metal, which might not help. In any case it's probably something you'd do reflexively, without thinking about the material composition of the kettle at all.
I am English, and was partly mimicking the parent who used "regular kettle" to mean "stove top kettle."
I did grow up with one though. My parents had previously lived in a house with a very small kitchen with no convenient place for an electric kettle. When they moved they kept their stove-top kettle until it burned through (about 10 years) and replaced it with an electric. I bought a stove-top kettle a few years ago for the same reason. It still comes out occasionally when an electric kettle breaks (which is quite often if you live in one of the "hard water" areas of Southern England.)
"when an electric kettle breaks (which is quite often if you live in one of the "hard water" areas of Southern England.)"
The trick is to every now and then turn the kettle on with no water in it. The calcium on the spiral at the bottom of the kettle will break into big chunks and fall off, if you just turn the kettle up side down they will fall out and you'll have a heating element as good as new (don't let it get too hot obviously, as that will damage the heating element and/or kettle itself).
There is a better way: just boil 100-200g of citric acid in a kettleful of water. It will dissolve the limescale with no damage to the heating element.
Yeah but it takes way longer if you need to remove a thick layer of calcium. What you can do is put in vinegar and then turn the kettle on. It improves the effectiveness of the vinegar, but it gets all frothy and stinks up your house. Also if you are are with your face over the kettle when you open it, the vinegar steam or whatever it's called stings in your eyes. So personally, my money is on turning the kettle on with no water :) (well actually my money is on buying a calcium filter, which is what I ended up doing in the end, but apart from that :) )
That will remove limescale from the heating element. Unfortunately some of it also finds its way into the auto-cutoff mechanism, causing it to switch off prematurely (or occasionally fail to switch off.)
But Americans do seem to speak as though their ways were universal, more than other nations. I remember a Canadian who worked near the border expressing her amazement at being asked "do you take normal money?"
Americans, to an absurd degree, are rabidly ethnocentric. I'm not sure why this is; I think it has to do with being the major superpower during the global information explosion era.
I'm speaking as an American myself: I have a very hard time, despite being conscious of it, not thinking of all things American as a baseline for normalcy. I know, intellectually, that American dialects stagnated for centuries after being imported from Britain and eviscerated by Webster, but I still think of "colour" as a foreign and exotic spelling.
I suspect one of the reasons for the popularity of small electrical appliances in Britain is that electricity is traditionally cheaper than gas, which is the opposite of what you'll find on mainland Europe.
> [in Britain] electricity is traditionally cheaper than gas
Rubbish, electricity is around 3x more expensive per KWh than gas in the UK. The UK has traditionally been a big gas exporter, too.
Electric kettles are used for convenience (faster, turns itself off) rather than financial reasons. Most people have little clue about what contributes what to their energy bills, too.
Presumably they are slower in the US because of lower mains voltage (x Amperage).
Back in high school, i visited the JET nuclear fusion project in Oxfordshire, they told us that they have to plan fusion experiments so they don't coincide with the end or commercial break of a soap, due to the tokamak requiring (i can't remember the exact figure) ~1 - 5% of the national grid's output.
if you can find it the BBC documentary "the secret life of the national grid" (3 episodes) is a fascinating look into the history of the UK National Electricity Grid
EDIT: You can find it on youtube if you do a search.
Unique British problem caused by tea. What must you Americans think of us? (is it true that Americans don't have enough power through the mains to boil a kettle?)
Is that tongue-in-cheek? Of course they can boil a kettle.
It does take ages, though.
Conventional kettles seemed to take perhaps twice as long to boil in CA than in UK. Boiling water at 230V,13A in the UK is going to be much faster than 120V,15A in the US.
Assuming you're heating 300 mL of water. The specific heat capacity of water is 4.2 J / (g°C) [3]. If you're heating it from 20°C room temperature to 100°C boiling, that's a temperature increase of 80°C. The metric system is set up so that 1 mL of water weighs 1 g (give or take a little based on temperature, pressure, impurities, etc), i.e. the density of water is 1g / mL. Plugging in the numbers:
So approximately 100 kJ of energy is needed to boil 300 mL of water. One kW of power is a delivery of one kJ per second.
How much power do we have available? In the UK, there's 230V * 13A = 2990 W ~ 3 kW. In the US, there's 120V * 15A = 1800 W = 1.8 kW.
So in the UK it takes 100 kJ / 3 kW ~ 33 seconds. (One kW is 1 kJ / s.) In the US it takes 100 kJ / 1.8 kW ~ 56 seconds.
These times are likely lower bounds. Assuming the voltage and current given by the parent are correct (or you measure them directly and substitute those numbers) and you measure out exactly 300 mL of distilled water, the biggest source of error is probably the fact that you're heating more than the water. You also have to heat the resistor in your kettle or electric stove, the thermally conducting, electrically insulating housing for the resistor, the kettle itself, and the surrounding air. And water molecules heat unevenly (my thermodynamics is a bit sketchy but I think this is called a Boltzmann distribution [2]?) so a few will evaporate before the water reaches a uniform 100°C, carrying off energy.
My guess would be that the above effects matter less in the UK because the higher power means they would have less time to operate.
I'm pretty sure that this analysis deals correctly with the fact that the current is AC [1]; if any experts on the mysteries of power engineering want to correct me, please do reply.
Branch circuit voltage sag, from running the vacuum on the same circuit as the room lighting. Doesn't happen in commercial buildings, where the lighting runs on 277v.
In the US in the places I've lived, Ive uses and continue to use municipal gas to cook, and boil water for tea. It heats up water fast. Doesn't strain the electric grid but has other issues.
If the power grid in the US drops to 57HZ, we're all boned.
Fun fact: Texas is the only state in the union with it's own power grid independent of other states. It is literally the only state that could successfully secede from the union.
Sorry, you mean Alaska and Hawaii have some sort of connection to the rest of the grid, and Texas does not? Or do you mean that Alaska and Hawaii are not states in the union?
Hawaii's energy needs are 90% based on imported oil. If they seceded, they'd go dark.
While Alaska certainly has the ability to make money off its oil, most of its heating, power and other needs is actually provided by diesel fuel. Add to that the fact that most of the jobs are either government or military related and other industries in the state rely heavily on government subsidies, the state would probably find itself in a real predicament if it cut off contact with its pimp.
At least in the U.S., they deliberately adjust the speed of the generators so that the frequency averages 60Hz over time. They may lose a few cycles during periods of high demand, but they make up for it later. The clocks in my house that are driven off line voltage are very, very accurate over the long term; I only need to adjust them when daylight time changes. (This is much more accurate than my wristwatch or my car's clock, which need frequent adjustment.) Since I don't have to set my alarm clock or time my cooking with split-second precision, this works out well.
They do. Most likely the frequency is adjusted during night hours (when there is less fluctuation) such that the average comes to 50 Hz (or 60 Hz in the US). (See [1].)
They do. Over a day, they end up getting the clock back to the proper time.
Keep in mind that in a complex power system (any modern system in an industrial company) that there are multiple interconnected power-generating elements. The difference between a motor and a generator is simply a function of the relative phase. that is to say, if there are two interconnected generators operating, the one that is slower will draw power from the other proportional to the relative phase angle between the two.
The story told is oversimplified, as they are only noting one particular type of event (turning on kettles at the end of a TV program), whereas in any complex interconnected power system, there are events that are much less predictable.
I suspect that in lots of systems that it is much less manual than the video shown.
Before they started making electric organs, Laurence Hammond's company made luxury AC clocks. The problem was that they didn't keep very good time because of fluctuations in the grid frequency. The story goes that he solved this problem by making gifts of his clocks to the executives of all the power companies in the areas he was selling in to, and within a few months, all his clocks were keeping perfect time.
Frequency as in the alternating current alternates direction fifty times a second (or sixty in some countries), not as in power usage is consistent throughout the day. This didn't change the frequency. (Disclaimer: I haven't finished watching the video yet.)
The main buffer for immediate sub-second changes in load is the rotating inertia of electricity generators (e.g. spinning turbines).
When the total power load of the network exceeds the power generation, the immediate load is taken from generators and they slow down. Alternatively if the total load drops, the turbines speed up as they have more mechanical power pushed into them than is being absorbed by the network.
You might think it would be easier to droop the Voltage (lower the load), but for a variety of reasons it works out much better to let the frequency drop (e.g. system frequency can be reliably measured over sub-second periods, frequency is the easily measured everywhere on the network independent of phase, simple control systems before there were electronics).
The whole network relies on this for control purposes. If a network goes out of synchronisation, very very bad things happen - designing for big electricity is true engineering :) e.g. hundreds of millions of people go without power for many hours e.g. design failures in substations and commercial loads can explode due to ginormous power changes!!!
The thing that stands out to me is how inefficient kettles are in terms of power usage. Is it a simple case of more power equals shorter time to boil? Is there a more efficient way to turn electricity to heat?
Of all the types of energy, it's easiest to turn other types of energy (such as electricity) into heat. That's why, when converting amongst other kinds of energy (such as light, or motion), a side effect is often heat (and things getting hot which don't need to be is a sign of an inefficient process).
Essentially the kettle just converts electricity to heat (very efficient) which heats the element inside the kettle which is transferred to the water surrounding it via conduction (also very efficient). There's almost no wasted energy, and you know that because the area around the kettle does not get hot.
Kettles do use a lot of energy because water requires a lot of energy to heat up - in fact it's among the highest of all substances (the measure of this is called the heat capacity or specific heat - the amount of energy to raise an amount of a substance by one degree Celcius/1 Kelvin.
If you want to be more energy efficient at boiling water, put only the amount of water you need in the kettle, rather than boiling extra, but obviously this is not a solution when scaling electricity infrastructure.
edit: I should note that Kettles are not completely efficient - there is still some energy loss (for instance, through resistance in the wiring in the kettle, and heat conducted to the kettle itself or radiated to the surrounding air).
Could one make a heat pump kettle that would be "more than 100% efficient", by moving head from the surrounding air into the water rather than just resistive heating? I remember seeing that approach recommended for heating houses.
Thanks for the information. I guess it's that I can't comprehend the scale required to make that much of an impact. It's easier (for me) to think at the single unit.
There's no such thing as an inefficient way to turn electricity into heat. A light bulb, a television, a fan, a refrigerator, a speaker, a kettle are all going to turn all of their power into heat.
And given the climate in the UK for most of the year the excess heat means your heating needs to do a little bit less[1].
1. But probably net less efficient in that the majority of houses in the UK use gas for their heating and gas is cheaper than electricy kWh for kWh in the UK.
There are some interesting consequences of this. I heard about a "Earth Hour" or something, a campaign for people to turn off their lights (or something) for a hour (or minute) to use less power.
However unless the National Grid can plan for how many people will do it (nigh on impossible), they'll probably wind up wasting power, and more people can be used preparing for everyone to turn things back on, resulting in Earth Hour/Minute actually use more power than if they'd done nothing.
Yes. This goes around every year Earth Hour comes up. It's a 1 hour shut down. If people actually did this, then yes, the coal power would stay on. Some would be stored (pumped hydro), but most will be burned off.
National Grid do have very good prediction, as per this (old) video.
I'm not sure I understand why the spike happens. Is there some etiquette that says you must wait until the T.V. show is finished before you may start making tea (why not switch the kettle on during a commercial break)? Also, is tea in the evening really that popular? Sorry if these are dumb questions, I'm not a tea drinker and I live in the U.S.
"Why not switch the kettle on during a commercial break?" The BBC doesn't have commercial breaks. Most UK stations that do have commercial breaks spread them out at about 20-minute intervals, so if you switched the kettle during a commercial break, it would have got cold again by the end of the programme.
Besides, if everyone switches the kettle on during the commercial break, you just shift the spike forward a bit.
There aren't commercial breaks on the BBC, it's funded by an annual license fee, so programmes generally run without interruption.
And yes, tea is that popular. In my office, each person will typically drink 3-4 mugs of tea during the day. Many people continue with at least two mugs when they get home.
I don't know about Top Gear, but Doctor Who is cut on reruns. It is broadcast in its entirety, albeit interrupted by commercials, on first showings (which means it runs long by about 15 minutes).
It really depends. Quite a lot of older people drink only tea. Young professionals living in London drink espressos, capuccinos, that sort of thing. I don't know anyone who drinks instant coffee (although I'm sure some people do).
Oh yes. People drink tea throughout the day. Basically black tea with milk and depending on the person sugar. Water is boiled in an electric kettle and poured onto tea bags.
Is there some etiquette that says you must wait until the T.V. show is finished before you may start making tea
It's not an etiquette thing, but more just co-incidence. When a TV show is over, lots of people might want a cup of tea and so it's more that lots of people are doing the same thing at the same time (i.e. a spike).
(why not switch the kettle on during a commercial break)
Channel that have ad breaks would have them every 15 → 20 mins, so the water would go cold.
Very interesting. I live just a few miles from the Dinorwig hydro plant that is mentioned and have been on a tour. It's and incredible feat of engineering - if ever you get the chance to go there (or somewhere similar), I'd recommend it.
Absolutely, I live quite near by to and highly recommend it to anyone interested, I've been a few times now, and would quite like to go again. For those who are interested: http://www.fhc.co.uk/ There's Ffestinog further south too, but there isn't a tour around that like the one at Dinorwig.
The fundamental issue here is that it's hard to store electricity, so that demand has to be met in realtime. This kind of problem should fade away as cheap grid-scale batteries become available in the next decade.
Reminds me of the apparently fake story that large numbers of people simultaneously flushing their toilets during breaks in the Superbowl damaging sewerage systems.
I wonder if some kind of evil flash mob could bring down the grid by having everyone turn on all their power hungry appliances at the exact same time.
If you want to make a flash mob big enough to do that you would need to post the information publicly. Then I think there's a good chance of word getting back to National Grid who could then plan for it. The only thing they wouldn't know then is the size of the demand.
yes they could bring down the grid that way. as you can see a million people turning on their kettles at about the same time is something that must be planned for. If it happens unexpectedly, it is unlikely the generation would be ready to be dispatched fast enough
I don't know why they say it's unique to Britain. I've visited a hydro station in South Africa a few times where they've shown me that surge, and South Africans have fewer television channels to choose from.
For me it just screams for the question what if that guy will not keep up or just will go to the bathroom? Power outage on the national scale? Frankly that story just blew my mind, all that seems so ridiculous in its hilarious epicness, but very thought provoking. And of course what I did first is checked was not it an April's Fool Day joke. Also the main property of stereotypes is that they often come out to be true. Great post.
One gobby bloke in my flat would take the lift and run out for his bits and bobs -- that spanner would come back after a fortnight with a hold-all and straight away put the kettle on, then have an ice lolly.
To be more detailed: For a given region, the algorithm schedules the lowest-cost sources first and keeps adding higher and higher cost sources until it reaches necessary generation capacity. Then, everyone is paid the same rate as the the marginal watt that just got scheduled. As a consequence, sources of power which cost money to shut down, like nuclear plans, will actually bid negative into the market to ensure they are scheduled. This is followed by low-marginal-cost plants like hydro dams. Then coal, which is relatively cheap. Then natural gas which is more expensive (or at least was before fracking) but the turbines for which can respond quickly. This actually happens twice as they run this market once the day before based on predictions and then run an adjustments market in real time. IT is actually possible to sell power in the day-ahead market and sell it in the real-time market without owning any generation capacity and do arbitrage. Another way to do arbitrage is to build two reservoirs and pump water to the higher one at night when power is cheap and then generate hydro power during the day when power is expensive [1]. You can also use flywheels or batteries. There are also markets for ancillary services like standing by ready to generate electricity or decrease generation with a few seconds' notice.
[1] http://en.wikipedia.org/wiki/Blenheim-Gilboa_Hydroelectric_P... Source for the rest of this: I interned at the New York ISO four years ago. Read more here: http://www.nyiso.com/public/about_nyiso/understanding_the_ma...