Concentrated Solar Thermal: A Complete Guide
Solar technology has come a long way in recent years, and there are now a number of different solar technologies available. One promising type of solar technology is called concentrated solar thermal.
Concentrated solar thermal (CST) technology uses mirrors to concentrate direct sunlight onto a receiver to produce heat.
This heat can then be used to generate electricity, power a process, or store it for later use.
This guide presents a comprehensive overview of concentrated solar thermal technology.
How Does Concentrated Solar Thermal Work?
Solar thermal energy is the use of solar radiation to provide heat. This can be done in two ways: either by concentrating the sunlight onto a small area to produce high temperatures or by using a collector to absorb the radiation and convert it into heat.
Concentrated solar thermal systems use reflectors to concentrate the sun's thermal energy and convert it into heat. This heat is then used to generate electricity or heat water or air for residential or commercial use.
There are many concentrated solar thermal technologies, each working differently, as explained below:
Types of Concentrated Solar Thermal Technologies
There are 4 main types of concentrated solar thermal technologies: parabolic troughs, compact Linear Fresnel Reflector, solar power towers, and solar dish engine.
Parabolic troughs
Parabolic troughs are the oldest type of concentrated solar thermal technology. Mirrors reflect the sun’s rays onto a pipe filled with fluid, which heats up and creates steam. The steam is then used to power a turbine and generate electricity.
Compact Linear Fresnel Reflector
A Compact Linear Fresnel Reflector (CLFR) is a type of linear concentrated solar thermal system. It uses a large number of small mirrors to focus sunlight onto a collector.
CLFR systems are more efficient than traditional parabolic trough systems. They can also be built at a fraction of the cost. However, they aren’t as widely used as other solar thermal systems.
Solar power towers
Solar power towers are a common type of concentrated solar thermal power plant. They use a large field of heliostats (mirrors) to focus sunlight on a central receiver on top of a tower.
The concentrated sunlight heats the receiver to a high temperature, causing the fluid inside to turn into steam. The steam is then used to drive a turbine, which generates electricity.
Solar dish engine
A solar dish engine is a device that uses solar energy to create mechanical or electrical power. Solar dish engines are made up of a large, parabolic mirror that concentrates sunlight onto a small receiver.
The concentrated sunlight heats the receiver, which then creates a hot gas that powers a turbine.
The turbine can be used to create mechanical power, which can be used to drive an electric generator. The mechanical power can also be used to create high-pressure steam and be tapped to drive a steam turbine.
The dish/engine system produces smaller amounts of electricity than other CSP technologies but is still less expensive to install.
Concentrated Solar Thermal Efficiency
The main advantage of solar thermal is that it can turn around 90% of the radiation it receives into heat. That’s much more efficient than other forms of solar energy, such as photovoltaic cells.
CSP technologies are becoming more and more popular, as they have the potential to be more efficient than traditional solar power technologies.
This, in addition to the fact that CST can be used to create both electricity and thermal energy, makes this technology highly attractive. What’s more, solar thermal energy is modular, meaning that it can be scaled up or down depending on the user's needs.
Where is Concentrated Solar Thermal Used? (Applications)
Concentrated solar thermal technologies are primarily used to generate electricity. The heat from the concentrated sunlight boils the fluid, which creates steam that powers a turbine to create electricity.
The thermal storage capacity of CST systems enables the generation of electricity round-the-clock. This provides a dispatchable resource to complement variable renewable energy sources such as wind and solar photovoltaics.
Other than generating electricity, concentrated solar thermal is also used in various residential and industrial applications. Some of the most popular uses include:
Heating water for residential and commercial use
The most common method of generating solar hot water for homes is the flat-plate collector. However, concentrated solar thermal energy is revolutionary for water heating.
The temperatures it can possibly achieve are much higher than traditional methods.
Utilizing concentrated solar power could decrease water heating bills for homes and businesses. CST plants, therefore, make an ideal choice for areas with high heating costs.
Water desalination
Seawater desalination is removing salt and other minerals from seawater to make it drinkable. It’s a critical process for supplying fresh water to coastal communities and cities. In many parts of the world, it’s the only option for meeting water needs.
Research findings show that CST could provide reliable, dispatchable power to run seawater desalination plants while significantly reducing greenhouse gas emissions.
Heating oil and natural gas
Concentrated solar thermal energy is well suited for crude oil heating purposes. The use of CST can help eliminate the need for gas-fired power plants and the accompanying emissions of greenhouse gases. In addition, it can also improve the efficiency of the refinery.
Manufacturing products such as asphalt, paper, and glass
CST can be used to make products currently produced with fossil fuels. The thermal energy generated with this technology can be used to heat up processes involved in the manufacturing of asphalt, paper, or glass.
A number of companies are currently using CST to manufacture products, and the technology is only becoming more popular.
Food processing
Concentrated thermal energy is used in industrial food processing facilities to preserve, prepare, and package food products. The most common use of concentrated thermal energy in the food industry is in the drying of products.
Thermal energy allows for a more consistent dry product while reducing the number of harmful bacteria.
Thermal energy can also be used to cook food or melt fat. All these are essential steps in many food processing methods.
Keeping crops and flowers warm in greenhouses
Concentrated solar thermal-powered greenhouses are another promising application of this technology. They can be used to grow out-of-season crops since they retain solar heat.
The retained heat can be used to keep the plants warm in colder climates or to extend the growing season in warmer climates. This allows farmers to grow crops all year round, which increases food production and helps to meet the needs of a growing population.
Mineral processing
CST has many applications in the mineral processing and extractive metallurgical industry. Some of these applications include:
- Heating process water and steam
- Heating up process gases
- Preheating of air or other gases
- Melting metals and minerals
- Ore concentration
In light of these applications, CST has the potential to play a major role in the mineral extraction industry.
How Much Does Concentrated Solar Thermal Cost?
The cost of a concentrated solar thermal system depends on the size of the system, the type of receiver, and the type of storage system. Generally, the cost ranges from $2,000 to $10,000 per kilowatt. The average is about $5000 per kW.
The cost of concentrated solar thermal is definitely higher than other solar technologies, but this is expected to decline as the technology matures and more companies enter the market. CST currently accounts for a very small share of the global solar market.
Advantages of Concentrated Solar Thermal
Heat water for residential or commercial use
Concentrated solar thermal technology leverages mirrors to concentrate the sun’s energy and use it to heat water for residential or commercial use.
CST systems are currently being used in many parts of the world, and there’re several advantages to using this technology:
High efficiency with low maintenance requirements
CST systems are often chosen because they are affordable and can provide heat for many years without requiring much maintenance. Additionally, CST systems are known for their high-efficiency rates and ability to reduce energy costs.
Emission-free sources of renewable energy
CST systems are a renewable energy source that uses the sun’s natural thermal energy to generate electricity. CST systems don’t produce any harmful emissions and can be used to generate power in both urban and rural areas.
Modular source of energy
Concentrated solar thermal systems are modular, which means they can be scaled up or down to meet the user's needs.
This is a huge advantage for two reasons. First, it makes these systems more adaptable to a wider range of users and applications. Second, it makes them more affordable for smaller installations.
Disadvantages of Concentrated Solar Thermal
The cost of concentrated solar thermal is higher than other solar technologies.
The cost of concentrated solar thermal is higher than other solar technologies. This is partly because CST systems require more mirrors and tracking systems than other solar technologies. In addition, the cost of land and water can be high for CST plants.
Requires extensive land area
Concentrated solar thermal technology has the potential to provide large quantities of reliable and environmentally friendly electricity.
However, there’re some locations where the concentration of solar thermal plants may not be able to supply the capacity of electricity needed due to a lack of available land.
Compare this to solar photovoltaics, which can be implemented in a much smaller area. What’s more, the large land requirement for CST systems also means that they are not suitable for use in high-density areas.
Potential negative impacts on the environment
The development of CST technology has caused growing concern among environmentalists and other groups about its potential impacts on the environment.
One major concern is that the large-scale deployment of solar reflectors could disturb the natural environment, in particular by affecting the local climate and ecology.
It has been proposed that the deployment of CST could lead to changes in local weather patterns, including an increase in temperature and a decrease in rainfall.
Is concentrated solar thermal better than solar photovoltaics?
There are many factors to consider when comparing concentrated solar thermal (CST) and solar photovoltaics (PV), but the most important distinction may be the amount of energy they can produce.
CST has the potential to generate much more energy than PV, making it a more efficient option in the long run.
Is CST applicable as a grid-level electricity source of electricity?
CST plants are able to store energy in the form of heat. That heat can be used at a later time to generate electricity, which could provide a grid-level source of electricity.
The storage capacity of CST plants is also much higher than that of batteries, meaning they can provide large-scale grid-level electricity.
Currently, the technology is also being looked at as a possible solution to the intermittency problem of renewables.
What are some future trends in CST technology?
There’re two main future trends you should keep an eye on regarding CST technology:
1. Falling costs of CST technology: The cost of CST has been dropping significantly in recent years, and this trend is likely to continue. This will make CST more competitive with traditional forms of energy generation.
2. Increased use of storage: As CST technology continues to improve, we are likely to see increased use of storage systems, which will help to improve the reliability and flexibility of CSP plants.
Wrapping Up
Concentrated solar thermal (CST) is a technology that uses mirrors to concentrate the sun’s energy and convert it into heat.
The heat is then used to produce steam, which powers a turbine that creates electricity. CST has many benefits over other forms of solar energy, including the ability to store energy for later use.
Despite its many benefits, CST hasn’t seen widespread adoption. One of the reasons for this is the fact that CST requires a large amount of land to be effective. Another reason is the high cost of building a CST plant.
Until these issues are resolved, CST won’t be able to compete with other forms of renewable energy such as solar PV and wind power. CST has the potential to become a major source of renewable energy, but more research and development are needed.
