Question

RSES Tutorial 2 (2017) The total UK electricity delivered to customers during 2014 was approximately 3 approximately 91.5% of the electrical energy available was delivered to customers, some 85% of the available electrical energy was lost in transmission and distribution 1 01.7TWh. In that year a) Determine the total electrical energy that was available (generated within the UK and net imported) during 2014. (329.7TWh) b) Determine the average UK electricity power consumed and the average UK power available over the year. (34.4GW, 37.6GW) c) Determine the annual energy produced contribution to the available energy, as a percentage, made by two 600MW power stations, one of which was operating for 82% of the time and the other operating for 76% of the time. (2.52%) 2 The distance of the Earth from the Sun is approximately 1.496x101" metres and the total power output of the Sun is approximately 3.825x1026 W. The International Energy Agency estimated that the total global primary energy supplied was approximately 1.575 x 10* kWh a) The Sun is an average star and our galaxy (The Milky Way) is thought to be an average galaxy. As a very rough estimate (Kornreich), there are 1x10 stars in our galaxy and there are 1x10ts galaxies in the universe. Make a rough estimate the total power output of all the stars in the universe. (4x10° w) b) Determine the total energy output of the Sun in one second, stating your answer in units of joules and kWh. (3.825x1026 J, 1.063x1020 kWh) c) Determine the time taken for the Sun to produce an amount of energy equivalent to the annual global demand. (1.5 us) d) Determine the surface area of a sphere of radius 1.496x10m. (2.812x10 m) e) Imagining a hollow sphere of radius 1.496x101"m centred on the Sun, all the power emitted by the Sun would fall on the inner surface of this sphere. Assuming the Sun radiates equally in all directions, determine the power falling on an area of 1 square metre of this surface. (1360 w) The value calculated for part e is the approximate solar power that is falling on each square metre of the Earth's upper atmosphere and on the satellites orbiting the Earth. f) The size of the active area of photovoltaic solar panel on the International Space Station is 35m x 12m. The solar panels are around 14% efficient, chosen for reliability above efficiency. Determine the total solar power falling on the panel and the power generated by the panel for the ISS. (571200v g) Earth's atmosphere reduces the total solar power falling on the Earth's surface at sea level to around 77% of the power falling on the upper atmosphere when the Sun is overhead and to around 73% when the Sun is 350 above the horizon. Determine the approximate solar power density on the Earth's surface at sea level from an overhead Sun and the power expected from the ISS panels if they were located there. (1047W.m,61580W) h) Determine the approximate solar power density on the Earth's surface at sea level from a Sun that is 35° above the horizon and the power expected from the ISS panels if they were located there. 58380W)

Answer 1