What is Concentrated Solar Power?
There are two main ways to generate solar power. The first and most popular method is photovoltaic. This is the process most people think of when they hear "solar power" because of the iconic solar panels it uses. The other method is concentrated solar power (CSP). This process utilizes mirrors to direct sunlight to a specific point where the heat can be absorbed and converted into energy. Let's take a deeper look at how CSP works.
How Does Concentrated Solar Power Work?
Concentrated solar power relies on mirrors that are placed and configured in a very specific way so that sunlight can be reflected onto a receiver. This receiver absorbs the heat from the sun's rays and converts it to steam. The steam is then used to power a turbine that produces electricity. While this is the general overview of how CSP works, there are four specific ways that this process is implemented.
This system uses curved mirrors that reflect sunlight onto a receiver pipe. Inside this pipe is thermal oil that is heated by solar energy and is then used in a thermal power block that drives a steam generator to produce electricity.
The power tower system is reliant on the use of heliostats. These heliostats are mirrors that can rotate on two axes and move to follow the sun as it makes its way across the sky. As the heliostats rotate, they are constantly redirecting sunlight to a receiver placed on top of a tower. Within the tower is a fluid, such as molten salts, that is heated by the energy. This fluid is then converted to steam which powers a turbine.
In the linear fresnel system, a large number of mirrors are placed in rows flat on the ground. Similar to parabolic troughs, these mirrors then redirect sunlight onto a receiver pipe placed above them. The oil inside the pipe is heated during this process and is then converted to steam.
As its name implies, this particular system uses a parabolic dish that tracks the sun and reflects its light onto a receiver. The heat from the redirected sunlight is then generated into usable energy by a heat engine.
Pros and Cons of Concentrated Solar Power
As with any solar power method, one of the biggest advantages of concentrated solar power is that it's a clean and renewable source of energy. Unlike photovoltaic alternatives, however, CSP provides a constant flow of energy instead of an intermittent one. This is because solar power generated using CSP is much more easily stored for future use.
Additionally, concentrated solar power is also much easier to integrate into preexisting steam power plants that currently rely on fossil fuels. It's also much cheaper to maintain and operate when compared with nuclear and hydrocarbon power plants.
However, concentrated solar power does also have some cons. First and foremost is location restrictions. Due to the high number of mirrors required to efficiently use CSP, it needs a large open space to be implemented in. This makes it hard to integrate into densely populated areas.
Secondly, because CSP uses turbines, it requires a large and reliable water source to operate. Furthermore, the high level of light can attract wildlife and the amount of heat generated can prove fatal for them.
Is Concentrated Solar Power Efficient?
Most CSP systems have a 7% to 25% efficiency. The discrepancy between those levels of efficiency is because the receiver, type of system, and engine used can all affect how well it operates.