The Dinorwig scheme, which is one of the UK's largest construction projects, was designed with minimum impact on the environment. The station consists of 6 × 300 MW generators with the turbines capable of both generating and pumping. In addition, the units have the facility of spinning at no load, giving rapid response times between zero and full load. The flexibility of the plant enables it to be cost effective, replacing high-cost oil or low-efficiency coal plant, particularly for short-run periods