The Duck Curve And Firm Power

Midday solar carves a deep belly into net load and a steep evening ramp; firm dispatchable generation is what climbs that ramp.

Reading the duck

When abundant solar is added, the net load, demand minus renewables, sags at midday and rises sharply as the sun sets while people come home. Plotted over a day the shape resembles a duck. Two features stress the grid: the deep midday belly, where inflexible plants must back down, and the steep evening neck, where several gigawatts must appear within a couple of hours.

A firm, flexible resource is valuable on both counts. It can reduce output during the belly and ramp hard up the neck. The burner (MetroVolt), designed to be dispatchable without steam-cycle inertia, is aimed at exactly this ramp.

The ramp is the challenge

The neck of the duck grows steeper as solar penetration rises. Meeting it requires resources that can move quickly and reliably. DEC removes the thermal-mass limit that slows steam plants, which is the design basis for a fast burner ramp.

Honest position

MetroVolt's ramp capability is a simulated design target, not a measured one. The stable operating band and achievable ramp rate depend on plug physics that sits 166 to 830 times beyond any operated device. The duck-curve fit is a motivating use case, contingent on the test program.