Environmental Engineering Reference
In-Depth Information
250
200
heat to
the storage
150
secured power
100
heat from
the storage
heat from
the storage
electricity
direct from sun
50
0
Figure 7.6
Solar thermal power plants with thermal storage can provide guaranteed
output around the clock.
appearance, these trough facilities were incredibly similar to those used today.
However, problems with materials and other technical diffi culties ended this fi rst
attempt at large-scale technical generation of solar electric power in 1914, shortly
before the start of the First World War (Mener, 1998).
In 1978 the foundations were laid in the USA for a resurrection of this technology.
The Public Utility Regulatory Policies Act obligated American public electricity
companies to buy energy from independent producers at clearly defi ned costs. After
the surge in energy costs in the wake of the oil crisis, the electricity provider
Southern California Edison ( SCE ) offered long - term feed - in conditions. The intro-
duction of favourable tax advantages fi nally made the construction of plants worth-
while fi nancially. The LUZ Company, which was founded in 1979, negotiated a
30-year contract for the feed-in of solar energy with SCE in 1983. In 1984 the fi rst
solar thermal parabolic trough power plant was built in the Mojave Desert in
California. By 1991 a total of nine SEGS (Solar Electric Generation Systems) power
plants with 354 megawatts of electric output were installed in an area of more than
7 km
2
. These power plants feed around 800 million kilowatt hours into the grid each
year, enough to satisfy the requirements of 60 000 Americans. Eight power plants
can also be operated with fossil fuels, thus enabling them to supply electricity at
night or during periods of bad weather. With these plants the annual natural gas
portion of the thermal energy supplied is legally set at 25%. The total investment
for the plants was more than US$1.2 billion.
In the mid-1980s energy prices fell dramatically again. Then the tax exemptions
also ran out at the end of 1990, and the LUZ Company went bankrupt even before
construction could start on the tenth power plant.
A long lean patch then followed for the planners of solar thermal power plants. It
lasted until 2006, when building work was started on new parabolic trough plants
in Nevada in the USA and near Guadix in Spain.
