Quiz: Are You an Electricity Expert?

We’ve all done it; you walk into a dark room knowing full well you’re in the middle of a power cut – and you flicked the light-switch all the same! It’s automatic; electricity is just there. We’re all so used to having it around, that just like water, we don’t really think about it and most of us don’t know that much about how it’s generated or gets to us either.

Are you one of the few who buck that particular trend? Are you an electricity expert? While the rest of us struggle to remember how to wire a plug, are you happily discussing resistance coefficients with your PV installer, or kilowatt hours with your energy supplier? Well, here’s your chance to test your knowledge with a few questions about Britain’s electrical supply, and how we use it in the home.

The answers are at the bottom, so have fun and good luck!

    1. Most of the UK’s energy is generated by:

    • a) Coal and gas.
    • b) Hydro electric.
    • c) Nuclear.

    2. How much of the UK’s electricity is generated from renewable sources?

    • a) 1.6 per cent.
    • b) 6.6 per cent.
    • c) 16.6 per cent.

    3. What is meant by the efficiency of electrical generation?

    • a) How much energy you can save by using high efficiency appliances.
    • b) How clean a power source it is.
    • c) The percentage of the original fuel’s energy that is turned into electrical energy.

    4. Electrical current is measured in:

    • a) Amps.
    • b) Volts.
    • c) Watts.

    5. Roughly how big is the carbon-cost of every unit of grid electricity?

    • a) Half a kilogramme of CO2 equivalent.
    • b) One kilogramme of CO2 equivalent.
    • c) Five kilogrammes of CO2 equivalent.

    6. Roughly how much electricity does the average UK household use per year?

    • a) About 400kWh.
    • b) About 4,000kWh.
    • c) About 40,000kWh.

    7. Which two colours are used for the earth wire in a standard UK plug?

    • a) Red and blue.
    • b) Yellow and green.
    • c) Brown and white.

    8. Normal UK mains voltage is taken as:

    • a) 50V.
    • b) 110V.
    • c) 230V.

    9. What is a kWh (kilowatt hour) better known as:

    • a) A unit of electricity.
    • b) The rating of a fuse.
    • c) The carbon equivalence of electricity.

    10. How long will a 20W low energy light bulb take to consume ONE unit of electricity?

    • a) 5 hours.
    • b) 15 hours.
    • c) 50 hours.


    1. (a) Around two-thirds of the UK’s electricity is generated in power stations burning coal or gas.

    2. (b) According to the Office of National Statistics latest figures 6.6 per cent of Britain’s electricity demand is met by renewable means.

    3. (c) Electrical efficiency is the percentage of the original fuel’s energy that is turned into electrical energy. The latest generation of combined cycle gas turbines can achieve almost 50 per cent efficiency, but for most of the rest around 30 per cent is fairly typical, meaning that 70 per cent of the energy is lost as heat.

    4. (a) The amp, short for ampere, is the unit of electrical current.

    5. (a) According to DEFRA, it’s 0.544 Kg of CO2 equivalent – about half a kilogramme per unit.

    6. (b) The average UK house uses around 4,000kWh of electricity per year – and a further 16,000kWh of gas!

    7. (b) Earth wires are yellow and green.

    8. (c) In common with the rest of the EU, Britain’s mains voltage is a nominal 230V, but in practice, it is often nearer to the ‘original’ 240V while many European countries which formerly supplied at 220V also keep to their old ways! Fortunately from a practical point of view, it makes very little difference when it comes to using appliances around the EU.

    9. (a) 1 kWh = 1 unit of electricity.

    10.(c) A 20W low-energy bulb will take an incredible 50 hours to consume 1kWh of electricity; the old-style 100W incandescent bulb it replaced would do it in just 10 hours.

    So, How Did You Do?

    • 10 – Sparky!
    • 7 to 9 – High Voltage!
    • 3 to 6 – Low Wattage!
    • 0 to 2 – Blackout!