Power distribution grids are subject to major challenges in implementing the energy transition. A high increase in photovoltaics and heat pumps, electricity storage and electric vehicles must be integrated through the distribution grids. A digital twin is a digital image of the power distribution network that opens up the growing amount of measurement data for operation and planning. With a digital twin, power distribution system operators can efficiently and reliably provide green power with at least 30% reduced investment costs. The digital twin makes the energy transition possible at affordable electricity costs and at the same time reduces CO2 emissions.