Kragelund et al. provides an interesting contribution to operations scheduling in liberalized electricity markets. They address the problem of profit maximization for a power plant participating in the electricity market. In particular, given that the plant has already been dispatched in a day-ahead market, the aim is to schedule production throughout an operation day while complying with the day-ahead commitments, referred to in the paper as tracking a predefined production reference. The authors refer to Fig. 2 for an example of a production reference plan for a power plant of DONG Energy. A minor objection applies to this figure. It should be noted that DONG Energy operates at Nord Pool, where such plans are piece-wise constant hour by hour. However, given both smaller and larger power ripples lasting for only minutes, the figure most likely shows the actual production of the plant. This indicates that the research may have been done at some distance to the reality of power operations. As opposed to formulating the tracking as a hard constraint, the authors penalize volume deviations between reference and actual production (tracking error) in the objective function. This is not entirely consistent with the balancing mechanisms in most electricity markets, since no (or only very small) deviations are acceptable.