Introduction to Concentrated Solar Power

Concentrated solar power can be described as a method of generating solar power by using mirrors or lenses. So basically in this type of solar power generation system lenses or mirrors will be used to reflect the sunlight to a receiver.

In recent years, the growing population and technological advancements have caused an increase in energy demands. The renewable energy sector has experienced unprecedented growth owing to the limited supply and adverse impacts of fossil fuels. Solar, wind, and hydropower plants are effectively replacing conventional methods of energy production.

Lately, however, another interesting technology has been gaining momentum for its considerable potential, despite not getting the attention it deserves. Concentrated Solar Power (CSP) utilizes mirrors and laws of reflection to generate electricity.

What is Concentrated Solar Power and how does it work?

CSP systems generate power by making use of mirrors or concentrators to concentrate sunlight onto a receiver, through which a heat transfer fluid is made to flow. This conversion of light to heat is used to drive a turbine connected to an electric generator to produce power.

Based on the type of concentrators used, there are currently four kinds of systems in use.

Solar Power Tower

This system uses a field of heliostats to concentrate sunlight onto the receiver located atop a tower. Heliostats are large mirrors that run on a tracker system and track the position of the sun to reflect sunlight onto a predetermined target. These systems work at higher temperatures than other CSP systems.

Parabolic Trough

These systems utilize curved or parabolic mirrors that are arranged in parallel rows to focus sunlight onto a receiver tube positioned along the center of a trough. They are the most commonly used CSP systems.

Fresnel Reflectors

These are similar to parabolic troughs, the difference being they use flat mirrors instead of curved mirrors. Flat mirrors provide a more reflective surface than a parabolic mirror in the same amount of space, which allows the capture of more sunlight.

Dish Stirling

It uses parabolic dishes to concentrate sunlight onto a receiver positioned at the focal point of the reflector. Unlike other CSP systems which use steam turbines, this technology makes use of a combustion engine to generate power.

CSP Plants and Thermal Storage

Concentrated solar power has been around for a long time, although being limited in use because of the complexity and costs involved in designing these plants. However, rapid advancements in technology have recently brought down the financial burden associated with it.

Molten salt is usually used as the heat transfer fluid in CSP plants as it can function at extremely high temperatures and can be used to store energy. These plants usually contain thermal storage to store the energy produced for later use. Currently, a two-tank model consisting of hot and cold tanks is generally used. This improves the overall efficiency of the system making it more reliable.

Future of CSP

Among all renewable energy sources, solar energy is the most abundant. Hence, CSP plants are becoming a competitive choice to aid renewable power production. Thermal storage is a lot cheaper compared to battery storage for the same amount of energy. This makes CSP systems the better option for large-scale power generation. Thermocline system of storage which uses only a single tank for storing thermal energy is gaining popularity, which can bring down the costs associated with it.

In the future, improvements in technologies and materials will further bring down the cost of these systems. Overall, it is an efficient and reliable solution for meeting future energy requirements.

The most common problem faced by the world today is the lack of power resources. Sources of power were fossil fuels, nuclear power, and natural gases. The consequences of these energy sources were, they were in a limited quantity in nature and took a lot of time in replenishing, thus the use of a renewable sources of energy came into existence. Widely used techniques in collecting these sources of energy are larger in dimension and created environmental issues. Considering the case of wind energy, mechanism used to convert kinetic energy of wind to electrical energy is done by rotating generator with the help of blades installed on the tip of the windmill. Blades that rotate with the power of wind are connected to gears that rotate the generator. A single rotation of blade can effectively rotate the gear multiple times thus generating much more electricity.

Just like all mechanism these structures also have disadvantages. The installation and transportation of equipment and machinery were expensive. Positioning of the windmills were also had to be taken into consideration as it should be placed at remote locations where there were less population. Windmills created threat to wildlife mostly for birds. Maintenance of these system were not economical. It consumed a larger area because each structure had to be placed at an adequate distance.

Considering all these disadvantages lead the invention of an advanced and more effective mechanism by a Russian based company named VORTEX. They named it VORTEX BLADELESS AEROGENERATOR consisting of a few elements that can produce electrical energy from wind. Vortex technology claims getting electricity from wind through oscillation, which can be used as a green energy.

Structure of bladeless turbine is structured cylindrically without any rotating blades which differs from the conventional wind turbines. Outer cylinder called MAST is designed to be rigid and has the ability to vibrate upon the action of wind towards it from any direction. An anchor is connected between mast and generator which is fixed at the bottom on the ground. Carbon fibre re-enforced polymer is used as the mast in the turbine due to its non-corrosive property and durability. Furthermore, carbon re-enforced polymer tends to have higher tensile strength which contribute to its rigidity and also prevent the turbine from tearing apart due to shearing force of wind and to support vibration motion.

When the wind strikes or passes the mast of the bladeless turbine it will create vortex or spinning motion of air. Vortex then exert forces with certain frequency on the mast. When the frequency of the force is equal to the natural frequency of the mast resonance will occur and eventually the mast will vibrate and oscillate, this phenomenon is known as VORTEX INDUCED VIBRATION. Vibration of the mast will create kinetic energy and this energy will be transformed into electrical energy by the generator.

Advantages that make bladeless turbine more popular are it can save a lot of space compare to conventional wind turbines as they require a large area of separation between two turbines. Oscillation of the bladeless wind turbine is very tiny and less aggressive than traditional turbines. The design of the turbine is simple and cost effective. Productivity can be increased by placing multiple units in the same area.

Solar energy is one of the freely accessible renewable sources of energy that is plentily available in nature. we can implement new innovative ideas in order to harvest those free energy from the windows of cars homes and even from the screens of our smartphones to enrich the power systems of our society. The problem in establishing new photovoltaic cells can easily be rectified by using these transparent solar panels.  The idea that can be highlighted is that we can simply implant the new generation of buildings with fashionable generative glasses so that they can function well.

The visible spectrum that we saw is a part of the electromagnetic spectrum, which is a kind of arrangement of radiations based on the increase or decrease of wavelength or frequency. It contains radiations such as infrared radiations, ultraviolet radiations gamma radiations, visible light, etc. The transparent solar cells that we have discussed earlier basically depend on a device known as transparent luminescent solar concentrators (TLSC). These devices are composed of organic salts which are capable of absorbing the solar radiations not only the visible portions but also the infrared and ultraviolet portions of the solar spectrum. These salts shine when it absorbs these radiations as a kind of response and these responses generate the power in a narrow photovoltaic cell that is attached to the window pane. The power that is generated is converted into electricity and carried towards the whole building or the grid. These can operate throughout with an efficiency of around 10%. As per the experts, we can generate around 40% of nations’ annual energy from one by ten of the overall 5 to 7 billion meters square of the glasses that the United states of America have. The potential of growth for this field is pretty clear.

The beginning of new startups in this field and their contributions leads to sustainable energy years ahead. A million dollars grant project from MIT subjecting ubiquitous energy has succeeded in portraying the production of electricity by scooping up power in the infrared spectrum. It also enables the blocking of complete solar heat and retains the building cool always. This venture has already partnered with the leading glass manufacturer namely NSG group who were very much impressed in these and also planted the same in the lobby of their own headquarters. A company which is established in Australia namely clear-vue has also come up with a slightly different idea where the TLSC is sandwiched in between two layers of glasses. Here also the infrared radiation is transmitted the only variation is that there doesn’t exist a coating at its exterior. It is an accepted technology and thereby the same Is implanted in the glass atrium of a shopping mall. A European team namely solar gaps have installed solar blinds in the office windows. The major advantage that this system provides is that it can mechanically orient along with the availability of sunlight at the current day. For every square meter, they planted around 100 watts of power can be produced which is enough for charging three laptops. Even the same technology is implemented in the Swiss strawberry farms, these panels remove the vital photons for power generation. They also help in photosynthesis and produce better yields.

We can use the same technology in our smartphone screens, A group of researchers from South Korea has demonstrated that a suitable mixture with a correct proportion of titanium dioxide and nickel oxide can produce power at small scales like the size of a smartphone it may not be able to charge the phone fully but these are sufficient for boosting the battery in the tight working schedules. It has its own limitations since these are newly innovated technology. It will be an unavoidable source of energy in the upcoming generations. As compared to the other renewable source of energies transparent solar can help out the cities carbon-free and more sustainable.