Environmental Engineering Reference
In-Depth Information
with space and water heating as a by-product, could considerably reduce
total greenhouse gas emissions from houses, particularly in cold climates.
Solar energy for transport
Energy for transport is one of the most difficult markets for solar-derived
energy to penetrate. Liquid fuels from biomass (e.g. ethanol) can power
vehicles, but only at substantial environmental cost if used on a large scale.
The private car in cities can be largely replaced by public transport, which is
much more energy efficient than a car and can be powered by renewable
electricity. Freight can be shifted to electrically powered trains. Lightweight
electric cars are more efficient than current automobiles for city use. It is an
open question as to whether significant private motor vehicle ownership can
be afforded in an environmentally constrained world.
Carbon sequestration
Carbon sequestration is a means to stop the carbon dioxide created by
burning fossil fuels from entering the atmosphere. It has been touted as a
means by which Australia's large coal resources could be utilised for many
more decades without adding substantially to the enhanced greenhouse
effect. One method of sequestration is to separate the carbon dioxide from
the products of combustion, compress it and pump it into saline aquifers.
Another method is to capture the carbon dioxide using rapidly growing
genetically modified plants. The plants use sunshine, carbon dioxide and
water to make biomass. This biomass can either be buried in the mine from
which the coal came, or dried and burnt in a power station to produce elec-
tricity. This method is, of course, a solar energy technology.
Current estimates for the cost that 'zero emission coal' electricity might
reach over the next decade or two are comparable with estimates for various
forms of solar electricity. Carbon sequestration may assist the transition to a
greenhouse-neutral energy economy in the period to 2050. The fossil fuel
industry is devoting considerable resources and political capital to the devel-
opment of methods of storing carbon dioxide from power stations under-
ground or in the ocean.
Sustainable energy in Australia
Solar energy collection technology is immature compared with fossil fuel
technology, and solar electricity is relatively expensive compared with energy
