Solar power tower

Brigthsource Tower Ashalim

Solar Two 2003

Pit Power Tower

Solar power tower systems, also known as central tower power plants or heliostat power plants, are a type of solar thermal energy technology. These systems use a large field of mirrors to concentrate sunlight onto a receiver on top of a tall tower. The concentrated sunlight heats a fluid, which is then used to generate electricity through a conventional steam turbine or in some cases, through newer thermodynamic cycles.

Design and Operation

The basic design of a solar power tower consists of three main components: the heliostat field, the receiver, and the power conversion system.

Heliostat Field

The heliostat field comprises a large number of flat or slightly curved mirrors that track the Sun across the sky and reflect its light towards a central point. Each mirror, known as a heliostat, is mounted on a tracking system that allows it to move and keep the sunlight focused on the receiver throughout the day.

Receiver

The receiver is located at the top of a tall tower, which can be up to 250 meters high. It absorbs the concentrated sunlight from the heliostats and transfers the heat to a working fluid. The fluid can be water, molten salt, or air, depending on the design of the system. Molten salt is a popular choice due to its ability to store heat, allowing the plant to generate electricity even when the sun is not shining.

Power Conversion System

The heated fluid is then used to generate steam, which drives a steam turbine connected to an electric generator. The electricity produced can be fed into the grid for distribution.

Advantages

Solar power towers have several advantages over other forms of renewable energy. They can generate electricity on a large scale and, when equipped with thermal storage, can provide power even during periods without sunlight. This makes them more reliable and predictable than some other forms of solar power. Additionally, the use of water as a working fluid can be minimized or eliminated in some designs, reducing the environmental impact in arid regions.

Challenges

The main challenges facing solar power tower technology include high initial capital costs, environmental concerns related to land use and the potential impact on wildlife, particularly birds. The intense heat around the receiver can harm birds flying through the area. There are also challenges related to the efficiency of energy conversion and storage, as well as competition from rapidly falling costs of photovoltaic solar panels.

Future Development

Research and development in solar power tower technology focus on increasing efficiency, reducing costs, and minimizing environmental impacts. Innovations in materials for mirrors and receivers, more efficient thermodynamic cycles, and better thermal storage solutions are among the areas of active research. The goal is to make solar power towers a more competitive option in the renewable energy landscape.