“Black-start capability” is the ability to restore a power plant to operation after a shutdown independent of the power grid, i.e. without relying on external electrical energy.
It is extremely important to have a sufficient number of black-start capable power plants in a transmission grid so as to be able to quickly resume grid operations after a widespread power failure.
Power plants with black-start capability – which in Austria are usually hydropower (storage) plants – can be used to ramp up generating units with no black-start capability. This is because unlike plants with black-start capability, other plants – especially thermal power plants – require a high level of electrical energy for their own use before they can provide electrical power themselves.