ARCHIMEDE: in China the first large thermodynamic power plant with parabolic trough collectors and molten salts
Archimede Solar Energy (ASE), Massa Martana (Perugia), an italian company of Angelantoni Group, signed a contract in China for the supply of solar receiver tubes for the first plant in the world producing electric energy with the solar thermodynamic technology , or Concentrated Solar Power (CSP) with molten salts and parabolic troughs.
The project started on 2013 and now is finally in its executive phase.
The first 15.000 tubes of the total 32.000 will be delivered within the end of 2015.
AKESAI SOLAR THERMAL POWER PLANT (ASTPP) plant will have 55 MWe power and it will be equipped with 15 hours thermal storage to produce electricity also whenever the sun is absent ensuring the dispaciability.
The plant is located in QINGHAI TIBET PLATEU, AKESAI COUNTY, GANSU PROVINCE.
A thermodynamic solar plant is actually a thermoelectric plant where the thermal energy necessary to operate the steam turbine, and therefore to produce electric energy, is generated catching the solar rays through a system of reflecting solar collectors or parabolic troughs.
The parabolic troughs, following the sun, collect and concentrate continuously the sun radiation on a receiver tube located in their focus.
Inside the receiver tubes there is a fluid that is heated by the solar rays from 290°C to 550°C: this value obtained using a molten salts binary mixture (40% KNO3, 60% NaNO3).
The Molten Salts technology was developed by ENEA in cooperation with the Italian industry since beginning of year 2000, inside the Archimede Solar Thermodynamic project, at that time managed by the Nobel Prize Carlo Rubbia.
The use of the molten salts, instead of the diathermic oil (presently used in this kind of plants), gives various advantages such as:
- Temperature Increase at the solar field exit up to 550°C against the 400°C obtained with the diathermic oils, with significant increase of the thermodynamic cycle performance of the electric production (approx.. 4 - 5% more);
- The molten salts do not present any danger in case of accidental leakage from the plant circuits because they are not inflammable, non-toxic and they become solid rapidly if in contact with the ground with the possibility to collect them with mechanical tools, without any kind of pollution. Furthermore as they are commonly used in agriculture as fertilizers, they are not dangerous to the environment.
- Dispaciability thanks to the high temperature thermal storage producing “Energy on Demand”.