Generating Electricity 7 3.2 e the need for the National Grid as an electricity distribution system including power use and responding to changing demand. 3.2 f The advantages and disadvantages of using different using different voltages of electricity at different points in the national grid to include transmission of electricity and use in the home selecting and using the equation P=VI

Starter – Start up times Type of Electrical Generation Start up time Where used? Nuclear Coal Oil Gas Hydroelectric

Transformers Transformer can change the voltage. They are found in several places in the national grid.

Transformers Step down transformer – makes voltage smaller Step up transformers makes the voltage larger

Is it step up or step down? 1 3 2 4 Where are step up transformer found in the national grid? Why are they used? Where are step down transformers found in the national grid? Why are the used?

A diagram of the National Grid is shown below. Explain how transformer A makes the national grid more efficient Transformer A supplies 950MW to the national grid at 475 000V. Write down the input power of the national grid in watts. Calculate the current . Explain the purpose of transformer B. Discuss how the national Grid maintains a reliable supply of electricity to consumers. You must explain How the demand for electricity changes through the day Which types of power stations generate electricity continuously Why HEP are so useful to the national grid. A B

Plenary Why does the national grid have to be flexible? When is demand the greatest? How can they vary the amount of electricity they provide to the grid? What types of electrical generating technologies are flexible?