Civil Engineering Reference
In-Depth Information
12.4.3
Bio-Power
Bio-power is the generation of electricity or heat from biomass resources. Main
technologies that are used for bio-power generation are direct combustion, co-fi ring,
and anaerobic digestion.
In a direct combustion method, which is the most common technology, waste
wood from agriculture and wood processing industries directly burns in a wood
burning boiler to generate steam. This steam will be used to spin a turbine which
spins a generator and therefore can generate electricity.
In a co-fi ring system, part of the petroleum based fuel is replaced by biomass,
which in result can reduce the emission of petroleum based power plants signifi -
cantly. In an anaerobic digestion technology, bacteria are used to decomposes the
organic waste and produce methane which can be piped and used to produce elec-
tricity or heat.
12.5
Hydropower
Using water in order to provide power for running a machine or to generate electric-
ity is known as hydropower. Hydropower plants can be generally categorized to
impoundment, diversion, or pumped storage types.
In an impoundment system which is the most common type of hydropower
plants, usually a dam is used to accumulate a river's water behind it. The stored
power in this accumulated water would be utilized as the source of power to run a
turbine. The spinning shaft of the turbine then generates the input power for an
electricity generator, which fi nally and in exchange generates electricity.
In a diversion type facility, a small stream of the river's water is branched out
from the main river body of water in a higher elevation. The diverted branch of the
river's water will be directed to a turbine in the plant and makes the turbine to rotate.
Similar to the previous method the spinning shaft of the turbine will be the initial
power to a generator which in exchange will generate electricity. The diverted water
in this process then will be redirected back to the main river in a lower elevation.
In a pumped storage facility, during the hours that the electricity demand is low,
the water energy will be stored by pumping water from a lower reservoir to an upper
reservoir. During the hours that the electricity demand is high, this water will be
released to the lower reservoir to create electricity, by using a turbine and generator
assembly, similar to the other discussed methods above.
12.6
Ocean Energy
Ocean energy is so plentiful that some researchers predict energy derived from
ocean waves alone could generate more than the current world energy demand.
But most of the technologies that can effi ciently utilize this hidden energy in
