Nuclear experts get it wrong and Ontario’s Bruce Power gets it right – 2013 September
By: Donald Jones, P.Eng., retired nuclear industry engineer.
The Ontario power grid has around 13,000 MW of nuclear capacity but only 2,400 MW of nuclear flexibility and even that comes with operating limitations (reference 1). Most grid flexibility is provided by combined cycle gas turbine generators (coal is being phased out) and by a part of the total hydro generation. The large amount of nuclear, hydro and combined heat and power baseload leads to periods of surplus baseload generation (SBG) where supply exceeds demand. The SBG is exacerbated by over 2,000 MW of installed wind/solar, soon to increase by several thousand more MW. When demand is low and wind generation is high this has led to shutdown of vital nuclear units. Changes made by the grid operator, the Independent Electricity System Operator (IESO), now allow it to dispatch down wind generation to reduce the frequency of nuclear shutdowns. The 2,400 MW of nuclear flexibility is provided by the eight units operated by Bruce Power and is much appreciated by the IESO since it enables the nuclear units to reduce power to accommodate increases in wind generation without having to shutdown and then be unavailable for two to three days. Wind generation does not need to be curtailed until the nuclear flexibility has been used up (gas and hydro generation would have already been minimized and exports maximized), maximizing wind generation. More nuclear flexibility should be welcomed to cater for the intermittent and variable wind/solar on the grid. However there appears to be some reticence amongst pro-nuclear organizations about promoting nuclear flexibility to support wind/solar generation on the power grid. Let’s take a look at what the experts say.