Generating electricity Flashcards
What are the environmental concerns of generating electricity?
Burning fossil fuels releases Carbon dioxide into the environment which reflects back heat that otherwise would escape into space - this causes the earth to heat up and is leading to global climate change
How do you improve efficiency of generating electricity?
In ‘normal’ power stations energy is wasted at every stage and they are around 35% efficient. The most efficient type of power station are combined heat and power stations - here waste heat energy is used to heat local homes and businesses. These can be up to 80% efficient
What are the energy sources used in generating electricity?
- fossil fuels (coal, oil and gas) which ate burned to heat water or air
- Uranium and plutonium which release energy from nuclear fission and are used to heat water
- Bio fuels that can be burned to heat water
What is ‘start up time’?
This is the time it takes for a power station to begin producing electricity after it has been ‘turned on’. Gas had the shortest start up time and is often used to meet ‘peak demands’ times.
What is decommissioning?
Nuclear power stations have limited operating lifetime of 20-30 years -after this time the very fabric of the buildings become so radioactive it isn’t safe to work in them. At this point the building has to be dismantled and safely disposed of.
What happens at pumped storage?
When the amount of electricity produced exceeds demand the surplus can be used to pump water to a higher reservoir. This water can then be released and generate extra electricity at peak times
How does hydro-electric power work?
Stations use falling water to turn turbines. A dam will hold back a river to form a reservoir. The water from the reservoir is allowed to flow through the turbines. The turbines then generate electricity
How does Tidal power work?
Stations are often built across river estuaries. As the time comes in, water flows through the turbines, which spin and generate electricity. As the tide falls the water again flows through the turbines.
How do Wind turbines work?
Wind causes the blades to spin, which if connected to a generator, generates electricity. The faster the blades spin, the more energy produced.
What are solar cells and how do they work?
Solar cells use the suns light to directly produce electricity.
What are solar panels and how do they work?
Solar panels use the suns heat to heat water meaning less electricity needs to be produced.
What is geothermal energy?
In some volcanic areas hot water and steam rise to the surface. This steam can be trapped and used to drive turbines.
