We are only able to extract energy
when the tide flows in one direction.
Electricity can be produced fo about 10
hours per day. This can be increased by
storing water in tidal lagoons.
Stream farms can have a small impact
on marine life. Barrages can affect the
environment for many miles.
In Britain we could generate 11kWh
per person per day from tidal power.
Water movement caused
by tides can be used to
turn turbines to generate
electricity.
We can have stream farms where turbines are set
out like an underwater wind farm or tidal barrages
that act like dams, allowing water to flow through
tunnels and turn turbines.
Electricity generated by stream
farms cost 29p per kWh whilst
barrages cost 59p per kWh. They
usually last for about 100 years.
Tidal power stations are about
85% efficient. Coal power
stations are about 30% efficient.
Stream farms can produce
about 6W per square metre
whilst barrages can produce
10-30W per square metre.