Arno's EnergyIdeas (47)
Must it always be high-voltage?
In Spain, the region of Andalusia offers not only an impressive legacy of monuments, fashionable beach-places and Europe's largest concentration of well-watered golf courses, but also demonstrates technical progress in research and use of solar energy. Here I can recommend a trip to the Plataforma Solar de Almeria (PSA) and to Andasol 1 to 3, Europe's first parabolic trough power plants and currently the largest solar power plants in the world. Both are located between Granada and Almeria - only 60 km apart from each other.
Let's start at the Plataforma Solar de Almeria
The Plataforma Solar de Almeria is located near the Spanish village of Tabernas. At this time, it is the largest European research and development center for concentrating solar power (CSP). Since its founding in the early eighties, the use of solar energy for generating electricity and hydrogen as well as systems for electrochemical water purification are developed. Already 28 years ago they made initial tests with parabolic trough solar systems for steam and heat. Today, among other things, the tests for a 100-kW system for the direct production of hydrogen, Hydrosol 2, are taking place here. Thoughts about this topic can be found in Arno's EnergyIdeas (30) from February 10, 2009.
Parabolic trough solar power plant Andasol 1 (right). In the background, the turbine and generator building and the two salt storage systems. The high voltage leaves to the left.
Photo: Arno A. Evers FAIR-PR
On our website you will find a report about the conduct of the research equipment and facilities (see links). Tabernas was mainly selected due to its intense solar radiation of over 3.000 hours of sunshine per annum.
Now to Andasol 1 to 3
Using a turbine with an output of 49.9 MWt, Andasol 1 is currently the
largest solar power plant in the world and the largest parabolic trough
power plant in Europe. Initiated and developed by the German company
Millennium AG, Erlangen, it was built and is now operated by a German-Spanish
consortium. Andasol 2 is in the testing phase, for Andasol 3, the
earthworks have begun. At Andasol 3, the Stadtwerke München (SWM, Munic public utility) is
involved as well. On a surface of 195 hectares (about two square
kilometers)for each power plant, oil is warmed up by concentrating solar power through 209.664 mirrors in 22.464 absorber tubes with a running length of almost 90 km (Skal-ET
technology)to 400 degrees C. Electricity is generated via heat exchangers with
conventional power plant technology (turbine and generator). At this 300 million-euro project, however,
a small information booth or even an information sign is missing after all.
The first parabolic trough power plants in the world were built in the 80s
- and are still operative - in California and Nevada, United States: They initially had
no storage capability. Andasol stores a portion of the heat in molten
salt, the storage capacity here is approximately 7.5 hours at full load. The
electricity produced by the generator is transformed to a higher voltage
and fed into the Spanish 400 kV high voltage system at a seven kilometers distant substation.
Here the Spanish energy company Endesa purchases it.
The substation has been built there, especially because of the new established big wind
power plants in this area.
Here the solar electricity, which in the end is generated by using
conventional power plant technology, is merged with the existing
electricity mix. In 2008 the Spanish electricity was generated from: 30.1% natural gas,
20.7% renewable, 19.3% nuclear power, 15.9% coal; 8.1% CHP, 3.3% fuel /
gas, 1.7% CHP with high efficiency, 1% others. This chart can be found on
the monthly Spanish electricity bills. Hence the electricity produced sustainable
is already 1.4 percentage points higher than the nuclear electricity...
At first glance, Andasol is convincing by its sheer size. On the second
glance the technology, however, is not a big step forward, especially
through the re-employed large centralized power plant technology and the
resulting high-voltage power supply required for the existing electricity
grid. For comparison: The high voltage grid network in Germany has an incredible
length of 1.6 million kilometers (1 mio miles). Perhaps a more decentralized philosophy
would be more appropriate? After all, it is just all about hot water.
Back in the hotel, the Residencia or Appartemento, one is looking forward
to a hot coffee and a warm bath. But stop: for this purpose electricity is
needed nowadays. Where does it come from? Ah yes, from the power-outlet. However, it had
to be transformed in various stages from its long-haul transmission
voltage of 400.000 volt down to 230V. But that’s just fine as it is how it
used to be and therefore this status quo is not at all questionable. Or not?
What all this has to do with hydrogen and fuel cells, or might have to do, everyone must figure out on its own. To simplify this decision-making
process, I recommend a visit to the cultural heritages of humanity in
Andalusia, e.g. the Mosque-Cathedral in Cordoba and the Alhambra in
Granada. Impressed and inspired by these unique architectural and
engineering services, not to forget the work of thousands of craftsmen, something should cross your mind.
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