Chemistry Reference
In-Depth Information
equipment at the plant which was used to ensure the
temperatures were maintained at a correct level. Work
is still going on at the plant to remove the nuclear
material safely.
Biomass and biogas
When any biological material, whether plant or
animal, is converted into energy, this energy is called
biomass
energy. It can be taken from animal or
plant materials in different ways:
●
by burning it, for example wood (Figure 6.15)
Figure 6.15
Biomass energy is produced by burning wood.
Figure 6.13
Workers wearing protective suits and masks at the
Fukushima power plant.
●
by pressing out oils that can be burned
●
by fermenting it to produce fuels such as ethanol
or methane.
At least 50% of the world's population rely on wood
as their main energy source.
In India there are millions of methane generators.
Methane generated by the digestion of animal waste
is called
biogas
. The biogas produced is used for
cooking, heating and lighting. The by-product of
this process is an excellent fertiliser.
Some countries have already experimented with
ethanol as a fuel for cars. Up to 20% of ethanol
can be added to petrol without the need to adjust
the carburettor. Brazil, which has few oil reserves,
produces ethanol by fermentation (breakdown
by enzymes) of sugar cane and grain, and uses it
as a petrol additive (Figure 6.16). The Brazilian
government has cut down its petrol imports by up
to 60% through using this alcohol/petrol mixture.
Hydroelectric power
Hydroelectric power (HEP) is electricity generated
from the energy of falling water (Figure 6.14). It is
an excellent energy source, and electricity has been
generated in this way for some time. For example,
the Hoover Dam in the US provides HEP for
the surrounding area. It is a very cheap source of
electricity. Once you have built the power station,
the energy is absolutely free. In some mountainous
areas of the world, such as the Alps, HEP is
the main source of electricity. One of the main
advantages of this system is that it can be quickly
used to supplement the national grid at times of
high demand. A disadvantage of HEP schemes is
that they often require valleys to be flooded and
communities to be moved.
Figure 6.14
A hydroelectric power station.
Figure 6.16
In Brazil cars use an ethanol/petrol mixture.
