While gains may have been seen in both the power and gas markets this week – the gains were not equal - that is to say that the corresponding clean spark spread prices continued to be squeezed with all the seasons (except Summer 12) slipping further when compared with the previous week. At these levels the economics don’t work and that explains the big shift from gas fired generation to coal (coal accounted for 39% of the generation mix on Monday compared with 24.8% the previous week). When we have these type of price moves it’s interesting to see the impact it has on the generation mix. For many decades the mix was always set with nuclear running first and always, followed by coal then gas with oil managing the peaks in demand. The shift in fuel prices then meant that gas started to takeover after nuclear forcing coal fired plants to become more flexible. Here we see again how a change in price has again forced a change to the mix!