my name is mwd

I suspect most people, myself included, just think that power stations are on all the time, but apparently not. At Reboot Britain it was explained to me that on the UK National Grid the power producing capacity changes due to demand. At times of low demand, less energy is produced, and a high demand some of the older, dirtier power stations are fired up to help.

This means that not all energy is equal. Energy used during peak demand has a higher CO₂ cost than than at low demand points. So, if you really care about the environment you really don’t want to be boiling your kettle when the National Grid is in dirty mode. But how can you tell?

One way is to look at the frequency of the electricity on the grid. Ideally the grid should produce AC electricity at 50Hz, but this drops as the National Grid is under strain, and rises as there’s spare capacity. If you don’t fancy wiring a oscilloscope to the mains yourself (and I advise you don’t!), you can look at Can I turn it on?, which will tell you whether the grid is straining or not. Clearly if the grid is straining then any load you put on it will cause the National Grid to fire up more polluting generators, and that’s clearly something you don’t want.

Yesterday saw the launch of an alternative approach, RealtimeCarbon.org, a website that tells you the current CO₂ output of the national grid. This is a very useful website that tells you the current CO₂ output of the National Grid, compared with the average. If the CO₂ output is above average, then clearly we’re generating dirty energy and thus again it’s probably not time to turn on the kettle if you can avoid it.

All well and good, but when you look at the two sites together, you’ll perhaps start to get a bit confused. Last night RealtimeCarbon was telling me that the NationalGrid was in a dirty mode, and I shouldn’t use electricity, but Can I turn it on? was telling me the grid was lightly loaded and it was a good time to make a cup of tea. This morning RealtimeCarbon was telling me the grid was in a cleaner energy phase (time to make tea!) but Can I turn it on? told me the Grid was loaded (so much for that cuppa then). What does one do?

James Smith, one of the smart peeps at AMEE, explained to me that what I was seeing was yesterday the grid had too many power stations on, thus polluting too much and had spare capacity, and this morning there’s not enough on at the moment so the energy is clean but the grid is straining.

The upshot of this is just to note that a single metric doesn’t tell you all you need to know. Despite both these sites seeming to contradict each other, they are in fact telling the same story, and you need to know both bits of information to make your decision – looking for that rare moment when the grid isn’t straining and the energy production is clean. Perhaps it’s time to invest in a thermos?