Solar with diesel: why a controller sometimes holds solar back

A diesel generator should not run at a very light load for long periods. Running lightly loaded wastes fuel per kilowatt-hour and can damage the engine over time, so manufacturers specify a minimum load.

When solar is added to a site that runs on diesel, the panels can produce more than the generator can give up. A hybrid controller watches the load and the generator, and limits solar output so the generator never drops below its minimum.

The result: solar supplies as much of the load as it safely can, and fuel use falls. When the grid is available, the same controller can run solar alongside it instead.

At Baghdad Precast Factory, Tanweer's 301.8 kWp plant runs alongside the grid and the factory's generators under a hybrid controller.

Use the sliders to change the factory's load and the sunshine, and watch how the controller divides the work.

Draft for review by a Tanweer engineer.