Monday, July 27, 2009
Wouldn't it be better? No, I don't think so! (Hot Air Oscar nomination)
The website realtimecarbon.org encourages people to be aware of the carbon intensity of the grid, saying "Wouldn't it be better if we could use power when it's greenest?". I am pretty sure that the answer to this question is No!
Imagine, for the sake of simple discussion, that we have a country in which on average half the electricity comes from baseload nuclear power (intensity, 20 g/kWh) and half from demand-following gas (470 g/kWh). And that at night, demand is 60% of the average, and 83% of the electricity comes from nuclear. And that in the day, demand is 140% of the average, and 36% comes from nuclear.
Under these assumptions, the nighttime grid intensity is 95 g/kWh, and the daytime grid intensity is 310 g/kWh.
People using the RealTimeCarbon service will be advised by the red flashing "carbon alert" icon to avoid using electricity during the day, and will be rewarded with feelings of green smugness if they go to great lengths to use electricity at night instead. They may delude themselves into claiming that they have reduced their carbon footprint. You could even imagine them selling carbon offsets based on this sort of electricity-consuming time-travel. But, in the cartoon world that I have just described, the time at which you use electricity makes no difference at all to the carbon emissions! Imagine that 1000 people all earnestly follow the RealTimeCarbon guidance and turn on their 1kW toasters in the middle of the night instead of during the day. What happens? Well, in response to the increase in demand, an extra 1MW of electricity is generated while their toasters are on; and this electricity (in my cartoon world) comes from the gas power stations being turned up just a little bit, whether they turn their toasters on at night or in the day. The true marginal impact of their consumption is 470 g per kWh, whenever they consume.
Now, I am not saying that this cartoon is a faithful representation of what's going on in the UK. Maybe in the UK there are some times of day that are "good" times to use electricity, and others that are "bad". But I think this cartoon proves that "knowing the grid average" doesn't tell you anything useful about that. And I think that the cartoon is a fairly good cartoon of the UK, since in the UK much of the really low-carbon electricity is wind and nuclear, both of which are (at present) not demand-following.
Moreover, I think that if people go to great trouble to check RealTimeCarbon for guidance on "when it is ok to consume", the end result may be a worsening of the UK carbon footprint! Here's two arguments why:
(1) I can imagine people inconveniencing themselves in order to switch on their equipment at night - their inconvenienced lifestyle may well use more energy (for example, when they wait up late for the RealTimeCarbon to go from red to green, they may keep the lights on for longer at night!);
(2) If people think that their electricity is "green" they may give themselves permission to consume more of it. (I know some people argue, for example, that "their electric car is powered by wind, therefore they can drive as much as they want, and it doesn't do any harm to the planet".)
I therefore nominate RealTimeCarbon for a Hot Air Oscar for "Best intentioned but most useless consumer-engagement".
Thanks to Kim West for pointing me to the website and asking questions.
PS - I posted a message on the realtimecarbon forum 3 days ago, querying another aspect of their methodology, and there has been no response.