The Solastor System provides world-leading, patented ‘Graphite Storage Technology’ to store and produce solar energy on demand – even at night or when the sun is not shining. Its cost efficiencies come from using solar collectors (toroidal heliostats) which are almost twice as efficient as other heliostats. These lower capital costs translate to lower electricity production costs.
The technology is a combination of three components: a solar thermal receiver (STR), control systems and toroidal heliostats. The superheated steam produced by this combination is directed to a steam turbine where it is converted to electrical energy, or to a destination that utilises the steam for commercial purposes such as food processing.
The Solastor System consists of a variable number of modules depending on the size of the project. Each module consists of solar thermal receiver (STR) located on top of a 24 metre high tower surrounded by up to 100 heliostats (tracking mirrors).
Each STR contains an arrangement of heat exchangers embedded in 10 tonnes of high purity graphite. The graphite used to store the energy collected from the sun is held in an inert atmosphere inside a steel casing. This allows the receivers to operate at high temperatures of up to 800⁰C with low thermal emissivity to minimise thermal losses.
The heliostats are programmed to follow the path of the sun and redirect its rays into the receiver. Each heliostat is calibrated on a continuous basis to ensure accuracy. At the end of the day, or if the graphite reaches maximum temperature (full storage), the heliostats are automatically stowed in a safety position and the receiver is closed and sealed.
When water is introduced into the heat exchangers, it is converted to superheated steam. The steam flow from each receiver is then combined in a common manifold and attemperated to the required temperature and pressure to be used in a multitude of applications. The steam can also be used to generate electricity by passing it through a turbine which drives a generator. The system can produce steam consistently at temperatures up to 530°C, which results in highly efficient electrical generation.
Once the steam has passed through the turbine, it is condensed back into water and re-circulated into the feedwater system. The use of air cooled condensers and the closed loop feedwater system allow the system to recycle its water with minimal losses, making it suitable in areas with a limited supply of fresh water.
Being modular, the Solastor System offers a high degree of scalability. As more modules are added it increases output.
Each module can collect and hold approximately 3MWh of thermal energy, however, the electrical output of a plant is determined by the efficiency of the turbine used.