Generating electricity and saving energy

What is a power station? Explain in your own words what is done there: where does the electricity it produces come from?

In a thermal power station, the following steps occur, but they are out of order: steam moves a turbine; coal is burned; the generator produces electricity; heat heats water and turns it into steam.

1. a) Order the sequence from start to finish.
2. b) What type of energy is stored in coal before it is burned?

A nuclear power plant heats water like a thermal power plant, but without burning anything.

1. a) What "fuel" does a nuclear power plant use?

1. b) State one advantage and one disadvantage of this type of power plant.

In a hydroelectric power station, there is a reservoir with water stored at height, as shown in the figure.

Explain where this power station gets its energy from and what device moves when the water falls.

Look at the wind turbine in the figure:

What moves the blades of a wind turbine? What energy does a wind farm utilise? In what type of locations do you think these wind turbines are installed?

Classify these energy sources into renewable and non-renewable: the Sun, wind, coal, water in a reservoir, natural gas, and uranium. Explain the difference between the two groups.

Put these stages of electricity's journey to your house in order: the sockets in your room, the power station, the cables on high-voltage pylons. Explain what happens at each stage.

Describe the complete journey of electricity from dammed water in a reservoir to your bedside lamp, naming all the steps: what moves when the water falls, what device generates the current, and how it reaches your home.

A town wants to supply itself with electricity using only solar panels.

1. a) What problem will it face at night and on very cloudy days?
2. b) Propose two solutions to have electricity during those times as well.

An LED bulb of $10\ \text{W}$ gives out the same light as an old bulb of $60\ \text{W}$.

1. a) Which one uses less energy to provide the same amount of light?
2. b) How many times more energy does the old bulb use compared to the LED?

A mobile phone charger plugged into the mains consumes $1\ \text{W}$, even when no phone is connected.

1. a) How many hours does it spend plugged in if it is not unplugged for an entire week?
2. b) How much energy does it consume in that week, in $\text{Wh}$? Hint: multiply power by time.

The internet router consumes $10\ \text{W}$ and is turned on all day, every day of the year.

1. a) How much energy does it consume in one day, in $\text{Wh}$?
2. b) How much does it consume in a year of $365$ days, in $\text{Wh}$?
3. c) Convert the annual result to $\text{kWh}$, knowing that $1\ \text{kWh} = 1000\ \text{Wh}$.

Why does turning off the light when leaving a room save energy, even if the bulb is small? Explain it by considering the amount of time it stays on.

In the living room of a house, there are $5$ light bulbs turned on.

1. a) If they are old bulbs, of $60\ \text{W}$ each, what is the total power consumption?
2. b) If they are replaced with LED bulbs of $10\ \text{W}$, which give the same light, what total power do they consume now?
3. c) How much power is saved by making the change?

Household appliances have an energy rating label with a letter, from A (those that consume the least) to G (those that consume the most), like the one in the figure.

1. a) Between two fridges of the same size, one rated class A and another rated class F, which would you buy considering the electricity bill?
2. b) The class A fridge is more expensive to buy; why might it be worthwhile in the long run?
3. c) Why does efficiency matter so much specifically for a fridge, which is plugged in $24$ hours a day?