Marginal abatement cost curves (MACC or MAC curves) are a way of showing both the cost of saving carbon, and also the size of the potential saving from that source. I’ve mentioned them before in a post about low hanging fruit offered by refurbishment. They are usually used at a policy assessment level, looking at […]
A lot of people find this blog through the post about the embodied carbon of tap water so I thought I’d do a quick follow-up post.
I found the water industry body, Water UK’s sustainability reports covering the period from 2001/2002 up to 2010/2011. This gave me all the data I need to update the old post, and also to put the figures in some sort of context.
Click on the table for a larger view.
I’ve added sparklines to the table of data to show the change in the indicators over time. It is a shame that several of the indicators used by Water UK have been discontinued and new ones have come in in their place which makes for some difficulties in comparisons. It’s interesting to note just how static annual household water use has been over the past 10 years, but unfortunately that indicator has now been phased out, in preference for a return to average daily use in metered and un-metered homes.
The embodied energy of water has varied quite a lot over the past decade, falling by 28% between 2003 and 2007, before climbing back up a little in recent years. Embodied carbon is down slightly, but shows no sign of a continuing decline. Water UK attribute the recent rise to an increase in the carbon factor of electricity, which makes up the majority of fuel use in the water industry.
The tables show that my previous rough calculations were not too far out, but certainly worth updating. The figure I arrived at before was 0.59 gCO2/litre. The Water UK figures are between 30% and 46% higher with the latest figures coming out at 0.79 gCO2/litre. The question this raises is where did my previous calculation go astray?