Solar cells convert light energy directly
into electrical energy. Solar panels heat
water for use in boilers or to generate
steam and turn electricity generators
ADVANTAGES
useful when small amounts of electricity
needed or in remote places
costs nothing to run
produces no harmful
waste/pollution
DISADVANTAGES
expensive to buy
reliant on lots of sunshine
you need lots of them to generate enough
power to be useful
they don't work at night
Wind
the force of the wind
drives the blades of a
wind turbine round,
turning an electricity
generator
ADVANTAGES
wind is free
good method for remote areas
produces no waste or greenhouse gases
DISADVANTAGES
wind turbines can kill
birds
turbines can affect TV reception
wind is unreliable
they also produce noise
pollution
Geothermal
Radioactive decay in rocks produces heat
energy, which sometimes naturally causes
water to rise as steam. This steam can be used
to drive turbines. If none is produced then
water can be pumped down to the hot rocks
where it runs through fractures, heats up, and
returns to the surface as steam
DISADVANTAGES
Most parts of the world don't
have suitable areas where
geothermal energy can be usd
ADVANTAGES
no fuel costs
no polluting gases are produced
reliable
Biofuels
A biofuel is any fuel obtained
from living/recently living
organisms, which is then used to
heat water to produce steam, as
in most fossil-fuel-run power
stations
DISADVANTAGES
land used for biofuel crops causes
loss of habitat
crops that could be used to feed
local people are instead used as
fuel
ADVANTAGES
produces less greenhouse gases than fossil
fuels when burned
(theoretically) carbon neutral
provides better fuel security for
countries that don't own oil reserves
Waves
Wave machines use the
kinetic energy of waves
on the surface of the sea
to drive electricity
generators
DISADVANTAGES
difficult to scale up wave
machines to produce large
amounts of electricity
wave machine must be able to withstand rough weather
don't produce a constant
supply of electricity
cables connecting wave
generators to the elctricity grid
spoil areas of coastline
ADVANTAGES
no fuel costs; the energy is
free
no harmful waste
produced
cheap to operate
can produce a lot of energy
Tidal
A tidal barrage is a barrier built over a
river estuary which uses the kinetic
energy of the moving water because of
the tides to turn electricity generators
DISADVANTAGES
there are few
suitable sites
tidal barrages destroy habitats
undwerwater rotting vegetation produces the
greenhouse gas methane
ADVANTAGES
very reliable, can be turned on quickly
tides are predictable
no fuel costs
not expensive to maintain
no polluting gases produced
Hydroelectric
A dam traps water from a river. It is allowed
to flow through tunnels in the
dam, which turns turbines and
in turn moves electricity
generators
DISADVANTAGES
dams flood farmland and push
people from homes
undwerwater rotting vegetation produces
the greenhouse gas methane
water quality and
quantity can be affected
downstream