Environmental Engineering Reference
In-Depth Information
enough to service entire towns or urban districts are currently in operation, mainly in
northern Europe (see
Figure 4.21
). Even larger applications are in the offing. In 2011,
Saudi Arabia unveiled the world's largest solar thermal plant, a 25-megawatt system that
numerous industrial processes require hot water, solar heating has great potential as an
industrial technology. However, in most cases higher temperatures are required than those
produced by typical flat-plate or vacuum tube collectors. Higher temperatures require
collectors that concentrate light using parabolas and mirrors.
Figure 4.21.
The large-scale solar heating system that supplies hot water to the town of
Marstal in Denmark, one of several pioneering projects in Scandinavia.
Source:
Marstal
Fjernvarme.
Over the last thirty years, the costs associated with solar thermal technologies have
fallen considerably. By now they have also reached a degree of technical maturity that
makes them reliable. Passive solar technologies are already cost-effective in most locations
for new buildings, but their development is limited by the slow turnover of buildings in
developed countries.
Solar hot water generation costs between 10 and 20 U.S. dollars (2005) per gigajoule in
countries, such as China, where the technology is widespread and therefore an economy
of scale exists. It is also economical in countries with plentiful sunshine. However, in
countries with little sunshine (800 kilowatt-hours per square metre per year), it may cost
