The Turlough Hill pumped storage plant is in the Wicklow mountains in the Irish Republic. It pumps water from Lough Nahanagan up to a reservoir 550 metres above it. (i) The scheme is described as using 2.3 million cubic metres of water. Calculate the total stored potential energy in millions of kWh if this quantity of water is pumped from the lower to the higher reservoir. Assume that the density of water is 1.0 kg 1, g = 9.81 m s, 1 cubic metre = 1000 litres and 1.0 kWh = 3.6 MJ. (4 marks) (ii) If this stored water is allowed to flow back down to the lower reservoir through a turbine with an efficiency of 87%, calculate the maximum number of hours that the plant will be able to supply its rated output of 292 MW. I (2 marks) (iii) Explain how the transmission of popular TV programmes creates a need for such pumped storage plants on the national grid.