Environmental Engineering Reference
In-Depth Information
Although environmental impacts resultant from energy use are usually directly
linked to the use of fossil fuels, there are also problems that originate in the use
of renewables, particularly if one evaluates the complete cycle, from “cradle to
grave,” of all the equipment and technology involved.
Because renewable sources presently make a modest contribution to the world's
energy consumption, these problems will receive more attention as the contribution
of renewables increases. The main impacts of the most important renewable
sources are the following:
- Liquid effluent discharges and the use of fertilizers for modern biomass production
contaminate groundwater aquifers with nitrates and other toxic substances and pose
massive threats to fish and sea life in general.
- Wind equipment causes noise and aesthetic pollution and working blades pose a threat
to migratory birds.
- Copper and lead found in the collectors and batteries used for solar energy result in the
accumulation of toxic wastes in the environment.
- The reservoirs used for small hydro interfere with local fauna and flora and conflict
with tourism.
Hydroelectricity plants, particularly the large ones, can seriously interfere with the
environment because they require building large dams and the flooding of vast
areas, changing water flows and blocking fish migration.
Flooding is an important indicator for the environmental impact caused by
dams, but it is not the only one. Among other impacts are population removal (tra-
ditional native populations included); the alteration of river regimes downstream
(which occurs after the dam has been built); sediment accumulation upstream; bar-
riers to fish migration; proliferation of algae (eutrophication), water plants, and
mosquitoes; extinction of endemic species; and loss of historical and archaeolo-
gical heritages and tourism. Dam bursts are another possible risk. The impact of
hydroelectricity enterprises can usually be estimated according to the power pro-
duced by hectare of reservoir. The larger this number, the lower the impact on the
environment. A typical number for hydroelectric plants is 22 kW/hectare.
Hydroelectricity plants in operation do not produce CO
2
or other pollutants re-
lated to fossil fuels, with the exception of CH
4
, which is produced by the decom-
