I wonder if Mike Hall is charging his Di2 from his dynamo? Brave move to go for electronic shifting in the TD!
There was at least one rider that used Di2 on last year's TD...the name escapes me at the moment. But yeah, with all the climbing and gear changes (to say nothing of the expense), that's a point of failure I'd think pretty hard about before adding to the mix.
It doesn't appear to be slowing him down so far.