6 ms·

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 ar

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. [1] http://en.wikipedia.org/wiki/Blenheim-Gilboa_Hydroelectric_Power_Station 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_markets/energy_market/index.jsp http://www.nyiso.com/public/about_nyiso/understanding_the_ma...

scrumper 14y ago
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.
- icegreentea 14y ago
  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. http://chrisblattman.com/2010/03/08/graph-of-the-day-canadians-pee-between-periods/ http://chrisblattman.com/2010/03/08/graph-of-the-day-canadia...
  - robocat 14y ago
    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 :-)
    - mprovost 14y ago
      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.
robocat 14y ago
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?
- RobAley 14y ago
  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.
  - robocat 14y ago
    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
    - RobAley 14y ago
      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..)

scrumper 14y ago

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.

icegreentea 14y ago
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. http://chrisblattman.com/2010/03/08/graph-of-the-day-canadians-pee-between-periods/ http://chrisblattman.com/2010/03/08/graph-of-the-day-canadia...
- robocat 14y ago
  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 :-)
  - mprovost 14y ago
    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.

robocat 14y ago

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?

RobAley 14y ago
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.
- robocat 14y ago
  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
  - RobAley 14y ago
    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..)