In electricity demand, the need for low-cost continuous, reliable supply can be distinguished from peak demand occurring over few hours daily and able to command higher prices. Supply needs to match demand instantly and reliably over time. There are number of characteristics of nuclear power which make it particularly valuable apart from its actual generation cost per unit – MWh or kWh. Fuel is a low proportion of power cost, giving power price stability, its fuel is on site (not depending on continuous delivery), it is dispatchable on demand, it has fairly quick ramp-up, it contributes to clean air and low-CO2 objectives, it gives good voltage support for grid stability. These attributes are mostly not monetised in merchant markets, but have great value which is increasingly recognised where dependence on intermittent sources has grown.