If I may ask, why exactly are abstaining? Just curious.
I don't like the idea of 'tax credits', nor am I happy about doubling the cost of the Carbon Tax by having the government pay the taxes back to its citizens- it would be cheaper/more efficient for the government to simply pay our carbon taxes for us (but I am also aware that, simply due to being unable to think of an alternative, I have provided similar propositions in my own environmental bills).
I don't know, I don't feel very educated about the subject, so I didn't mount any sort of strong opposition, but I felt that the approval didn't need to be unanimous...