# P3.1 How much energy do we use?

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• Created by: sofsdvds
• Created on: 03-05-16 10:45
What are the issues raised by the continually increasing demand for energy?
The availability of energy sources and the environmental effects of using these sources
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What are the main primary energy sources that humans use?
Fossil fuels (oil, gas, coal), nuclear fuels, biofuels, wind, waves, and radiation from the Sun
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Why is electricity a secondary energy source?
because electricity is generated by using primary sources
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Explain how power stations generate electricity?
1. Energy is released from burning fossil fuels, 2. This energy is used to boil water to create steam 3. The steam turns a turbine 4. The turbine turns a generator which turns kinetic energy into electrical energy
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What do power stations produce when burning fossil fuels and what does this contribute to?
Power stations which burn fossil fuels produce carbon dioxide which contributes to global warming and climate change
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What happens when an electric current passes through a component or device?
Energy is transferred from the power supply to the component and/or to the environment
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What is power?
The power (in watts, W) of an appliance or device is a measure of the amount of energy it transfers each second, i.e. the rate at which it transfers energy
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What is the equation to calculate the amount of energy transferred in a process?
Energy transferred (kilowatt-hour, kWh) = power (kilowatt, kW) x time (hour, h)
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What is the equation to calculate the rate at which an electrical device transfers energy?
Power = voltage x current
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Why does a domestic electricity meter measures the energy transfer in kilowatt hours?
A joule is a very small amount of energy
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What is the equation for the cost of electricity?
Total cost = number of units x cost per unit
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What is a Sankey diagram and what do the arrows show?
A Sankey diagram is an energy transformation diagram and the thickness of the (input, useful output and wasted output) arrows shows how much energy is being transferred
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What is the efficiency equation?
Efficiency = (useful energy transferred ÷ energy supplied) × 100
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How can people reduce their energy usage?
Stop heat escaping from their homes by using; cavity wall insulation, loft insulation, double glazing, draught-proofing, hot water tank jacket, thick curtains, buying efficient appliances and energy-saving light bulbs, turning lights off
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How can businesses and government reduce energy usage?
Reduce photocopying, incentives e.g. public transport, car-sharing and cycling, grants for insulation, trade in old boilers, investing in alternative energy sources, recycling and laws to make sure new buildings are efficient
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## Other cards in this set

### Card 2

#### Front

What are the main primary energy sources that humans use?

#### Back

Fossil fuels (oil, gas, coal), nuclear fuels, biofuels, wind, waves, and radiation from the Sun

### Card 3

#### Front

Why is electricity a secondary energy source?

### Card 4

#### Front

Explain how power stations generate electricity?

### Card 5

#### Front

What do power stations produce when burning fossil fuels and what does this contribute to?