Renewable Energy
Explain how solar panels generate electricity without using a turbine.
Photons in sunlight strike the solar panel and cause electrons in its metal wires to move directly, creating an electric current
Describe the full energy transformation chain in a coal-fired power station, from burning coal to producing electricity.
Chemical energy (coal) → thermal energy (heat) → kinetic energy (spin) → electrical energy
A power station takes in 500 units of chemical energy and produces 175 units of useful electrical energy. What is its efficiency?
35%
Wind and hydropower both use turbines, so why is hydropower generally considered more reliable than wind?
Hydropower stores water behind a dam, so operators can release it on demand regardless of the weather
Advantages of non-renewable resources
Reliable and constant, more cost effective
According to the lesson, why is no energy transformation ever 100% efficient?
Some useful energy is always "lost" to the surroundings during the transformation, usually as heat or sound.
Electricity generated from renewable energy sources would be better for the planet because it produces little or no ___ and will not run out.
Air pollution
"All non-renewable energy sources work by burning fuel to release heat." Is this correct? Or not? Explain.
It is not accurate for nuclear energy where no burning occurs at all. Instead, heat is released from the nucleus of atoms through a nuclear reaction.
A coal power station converts chemical energy into electricity at an overall efficiency of 38%. If the turbine's mechanical efficiency is 90% and the alternator's efficiency is 95%, what is the approximate efficiency of the boiler?
(Hint: Overall efficiency = boiler efficiency × turbine efficiency × alternator efficiency)
44.4%
The fastest-growing renewable energy source in the world (2026) is
Solar
What are five specific environmental impacts of mining nonrenewable resources?
Creating toxic chemicals, destroying biodiversity, causing water and air pollution, habitat destruction from land clearing, etc.
Two power stations both need to produce 300 units of useful electricity. Station A is 30% efficient. Station B is 60% efficient. How much total energy input does each station need? Why higher efficiency matters?
input = output ÷ efficiency.
Station A: 300 ÷ 0.30 = 1,000 units of input needed
Station B: 300 ÷ 0.60 = 500 units of input needed.
The more efficient a station is, the less fuel it burns (and less waste it creates) to make the same amount of electricity.