Background and status of CSP

In Concentrating Solar Power (CSP) plants, mirrors focus sunlight to generate heat and steam, producing electricity through a conventional thermodynamic cycle. Unlike solar photovoltaic (PV) systems, which utilize both direct and diffuse sunlight, CSP utilizes only the direct component known as Direct Normal Irradiance (DNI). CSP plants can integrate a heat storage system, allowing for electricity generation even during cloudy weather or after sunset. Thermal storage substantially enhances the capacity factor and dispatchability of CSP in comparison to PV and wind power.

It is possible to classify CSP systems according to the mechanism by which the solar collectors concentrate solar irradiation: either “linear concentrating” or “point concentrating” varieties. Most existing systems use linear concentrating systems called parabolic trough collectors. Solar towers, sometimes also known as power towers, are the most widely deployed point concentrating CSP technology, but represented only around a fifth of all systems deployed at the end of 2020. For application at AB InBev, we are focusing on parabolic trough collectors since they are the only proven scalable solution for industrial heat generation. (Simbalotti, 2013)

Parabolic Trough Design:
The parabolic trough consists of long, curved mirrors (parabolic reflectors) arranged in a trough shape to focus sunlight onto a linear receiver located at the trough's focal point.

Sunlight Collection:
The parabolic shape of the mirrors concentrates sunlight onto a receiver tube that runs along the length of the trough. Sunlight is effectively collected and concentrated onto this tube.

Receiver Tube:
The receiver tube contains a heat-absorbing fluid, often a heat transfer oil or molten salt, which is heated as it absorbs the concentrated solar radiation. The temperature of the fluid can reach very high levels.

Heat Transfer:
As the concentrated sunlight heats the fluid inside the receiver tube, the thermal energy is transferred to the fluid. The high temperature of the fluid is crucial for efficient energy conversion.

Heat Storage and Transfer:
The heated fluid is then used to generate steam or directly transfer heat to a storage system, depending on the specific CSP design. In some systems, the heat can be stored for use during periods when sunlight is not available, enabling continuous power generation.

Steam Generation:
If steam is produced, the high-temperature fluid is used to heat water and generate high-pressure steam. This steam is then directed to a turbine.

Electricity Generation:
The high-pressure steam drives a turbine connected to a generator, producing electricity through the rotation of the turbine.

Power Distribution:
The electricity generated is then distributed to the grid for use in homes, businesses, and industries. Parabolic troughs are an efficient and established form of CSP technology, capturing and converting solar energy into electricity through a relatively straightforward process. The ability to store thermal energy allows for continuous power generation, making CSP a reliable renewable energy source.