Environmental Engineering Reference
In-Depth Information
2.3.5 Renewable Energy
Research into future alternatives has been and is still being conducted to
solve today's complex problems such as the rising energy requirements
of a rapidly and constantly growing world population and global envi-
ronmental pollution. Therefore, options for a long-term and environmen-
tally friendly energy supply have to be developed that lead to the use of
renewable sources (water, sun, wind, biomass, geothermal, hydrogen) and
fuel cells. Renewables could shield a nation from negative effects in the
energy supply, pricing and related environmental concerns. For many
years, hydrogen (for fuel cells) and the sun [for photovoltaics (PVs)] have
been considered as likely and eventual substitutes for oil, gas, coal and ura-
nium. They are the most abundant elements in the universe. The use of
solar energy or PVs for everyday electricity needs has distinct advantages:
avoiding consuming resources and degrading the environment through
polluting emissions, oil spills and toxic by-products. A 1-kW PV system
producing 150 kWh each month prevents 75 kg of fossil fuel from being
mined. It avoids 150 kg of CO
2
from entering the atmosphere and keeps
473 L of water from being consumed. Electricity from fuel cells can be used
in the same way as grid power—to run appliances and light bulbs and even
to power cars because each gallon of gasoline produced and used in an
internal combustion engine releases roughly 12 kg of CO
2
, a greenhouse
gas (GHG) that contributes to global warming [67].
Sunlight is not only inexhaustible but also only energy source that is
completely non-polluting. The World Summit on Sustainable Development
held in Johannesburg in 2002 committed itself to 'encourage and promote
the development of renewable energy sources to accelerate the shift towards
sustainable consumption and production'. Accordingly, it aimed at breaking
the link between resource use and productivity. This can be achieved by the
following:
1. Trying to ensure economic growth does not cause environmental
pollution
2. Improving resource efficiency
3. Examining the whole life cycle of a product
4. Enabling consumers to receive more information on products and
services
5. Examining how taxes, voluntary agreements, subsidies and regula-
tion and information campaigns can best stimulate innovation and
investment to provide cleaner technology
Until 2002, renewable energy contributed as much as 20% of the global
energy supply worldwide [79]. More than two-thirds of this came from bio-
mass use, mostly in developing countries, some of it unsustainable. Yet, the
