Environmental Engineering Reference
In-Depth Information
energy is usually associated with large environmental impacts arising from
the drowning of river valleys and the alteration of river hydrology. These
energy forms could contribute modestly in particular regions to an environ-
mentally responsible energy supply.
Energy issues
In public discussions about energy concerns, a number of issues are raised
both in favour and against the widespread use of solar energy. In addition,
considerable confusion has arisen in public debate about the roles of hydro-
gen, fuel cells and carbon sequestration in the sustainable energy economy.
This section briefly discusses these issues.
Energy efficiency
Hand in hand with the utilisation of solar energy goes energy efficiency, that
is, measures to ensure that the least possible amount of energy is required to
complete the task. For example, an energy-efficient building is a building
that utilises natural solar light and heat sensibly. Walking rather than driving
uses a small amount of solar energy (biomass in the form of food) rather
than a larger amount of oil energy. Clothes lines, solar salt production and
putting on extra clothing displace electric clothes dryers, fossil fuel fired kiln
drying of salt and gas or electric heating respectively. Australia has one of the
highest per capita energy consumptions in the world, and major reductions
in greenhouse gas emissions are readily achievable from a concerted energy
efficiency program.
Energy storage
Energy storage issues are not likely to prove to be major obstacles to mass
utilisation of solar energy. However, considerable work will be required on
storage once solar energy begins to be a major part of electricity supply.
Solar energy is generally less predictable and despatchable than energy
supply from fossil fuels. However, fossil fuel generation is not completely
reliable. The question to be solved is how to ensure that the probability of
failure of energy supply in a solar-dominated energy mix is similarly small to
that in a fossil fuel dominated energy mix.
A number of storage options are available, including thermochemical
energy storage, pumped hydro, flywheels and compressed air. There are
many options for the storage of low temperature solar thermal energy (for
