p3 Flashcards
where does the most the energy we use come from
fossil fuels such as oil, coal or gas
what is a biofuel
any fuel obtained from living or recently living organisms
what are benefits of biofuels
renewable sources of energy
carbon neutral
give some examples of biofuels
waste vegetable oil, methane, ethanol
what fuel is used in nuclear power stations
uranium or plutonium
how is uranium used in a nuclear power station
nucleus of uranium atom is unstable and can split in two which releases energy.
there are lots of uranium nuclei in the reactor core and the energy releases is used to heat water turning into steam
what are examples of renewable energy
wind, waves and the tides
how do waves produce energy
movement of waves in the sea drive a floating turbine that turns a generator.
how does a hydroelectric power station work
water is collected at a reservoir at the top of a hill and when the water flows down the hill it turns turbines.
what happens at a hydroelectric power station when demands are low
the same water is pumped from the bottom of the hill to the top to be used again
how does a solar cell work
transfers suns electromagnetic energy directly into electrics energy.
why are solar cells only used to power small devices
as each cell only produces small amount of energy
what can a large number of solar cells create
solar panels
what do solar heating panels do
use the suns energy to heat water directly
what does a solar power tower do
uses thousands of mirrors to reflect sunlight onto a water tank which heats water and produces steam which then drives turbines
what is geothermal energy
comes from energy releases by radioactive substances .
how does a geothermal power station work
very deep holes are drilled and cold water is pumped down to the hot rocks and the water Is heated and comes back s steam which drives turbines
what are some disadvantages of fossil fuels
non renewable resources
when they are hurt, greenhouse gases are released
burning coal and oil produces sulphur dioxide which causes acid rain
what are the advantages of nuclear power
do not produce greenhouse gases
transfers much more energy per kg than fossil fuels
what are the disadvantages of nuclear power
used fuel rods contain radioactive waste that must be stored safely for centuries
an accident can make the surrounding area unsafe for years
what are some advantages of renewable energy sources
they will not run out
do not produce greenhouse gases
what are some disadvantages of renewable energy resources
cant currently meet world demand for energy
wind tidal and hydroelectric can affect plant and animal life and can be eye sore
what is base load demand
the constant amount of electricity provided by nuclear and coal fire power stations
how is seasonal variable demand met
using gas fired power stations and pumped storage schemes
when are renewable energy resources used
when demand is high and the conditions are suitable
what power station shave the longest and shortest start up time
nuclear is longest
then coal and oil
natural gas is shortest
what is a renewable resource
a resource that is used up as quickly as its used
what type of area is good for a tidal power station
significant difference in water level between high and low tides
space to build a barrage across the river
why is a pumped storage power station good for meeting surges in demand
when demand is low, energy from other power stations pump the water back to the top of the hill.
