The energy consumption for a small factory is given at the end of the brief.

a) Three commercial tariffs from an energy supplier are shown below. Using these (or other commercially available tariffs), determine the most suitable tariff for the factory detailed. Your answer must be supported by mathematical analysis.

Tariff A

Standing charge per quarter of £21.95 and every unit is charged at 19.93 ppu

Maximum demand is charged at £6.95 per KVA per annum

Tariff B

All units are charged at 25.70 ppu

Maximum demand is charged at £5.95 per KVA per annum

Tariff C

First 1500 units in a quarter is charged at 21.82 ppu

All additional units in the quarter charged at 18.49 ppu

Maximum demand is charged at £7.45 per KVA per annum

b) Suggest changes to the working practices of the factory detailed in order to reduce the energy consumption and the cost of the energy bill.