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.
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.
[0] http://en.wikipedia.org/wiki/New_Electricity_Trading_Arrange... [1] http://www.bmreports.com/bwx_reporting.htm