My bike is fitted with a power meter (Quarq DZero) so I was able to track my power output whilst riding. The following graph shows the average power for each stage (red points) along with the time spent riding each stage (blue bars). The Green dashed line indicates the turnaround at Munich.
It is interesting to correlate the variations in power output with my ride notes and preparedness for each stage: Stages 1 (the start), 9 and 10 (leaving the conference) were preceded by one or more rest days, so are expectedly higher than average. In particular, Stage 9 was a short stage and a dash to avoid the torrential rain that followed me from Munich to Straubing. Stage 14 was the 'TT' up East England with flat terrain conducive to sustaining a higher average power, and was also proceeded by a shorter stage in The Netherlands which afforded 6-8 hours more rest and an extra meal. For the lows, Stage 4 involved crossing central London with stop/starts every few hundred meters for traffic lights, whilst 6 I expect was due to a late finish the day before which cut into sleeping time (the blue bars do not include stopped time so the actual time outside could be significantly longer).
The total energy expended (power ∗ time ∗ human efficiency) over the 16 stages amounted to roughly 81,000 Kcal or 5,000 Kcal a day on top of my normal daily expenditure (RMR).