What Is Solar Thermal Energy?
Solar thermal energy is the use of solar energy to produce heat.
This is an effect you’re familiar with if you’ve ever gotten into your car after it has been parked in the sun on a hot summer day. Solar thermal energy works in the same way except that the heat generated is put to practical use to heat water or space heating.
There are two main ways of generating energy from the sun:
-Concentrated Solar Thermal (CST)
This is an effect you’re familiar with if you’ve ever gotten into your car after it has been parked in the sun on a hot summer day. Solar thermal energy works in the same way except that the heat generated is put to practical use to heat water or space heating.
There are two main ways of generating energy from the sun:
- From Light - Photovoltaic (PV) and
- From Heat Solar Thermal –
-Concentrated Solar Thermal (CST)
Direct Solar Thermal
Solar thermal is heat generated by letting the rays of the sun fall directly on a vessel or on a group of zig-zag copper pipes. To increase the effect of the sun and increase the heat you may paint the pipe black. You could also use a lens so that the sun’s rays converge at a single point thereby increase its heat intensity.
Indirect Solar Thermal
But what if the sunlight is not sufficient? Then you could use a plain mirror, group of mirrors, concave mirror or a group of concave mirrors to focus the sunrays to converge on a single point. The heat generated thus at that point could be very great… sometimes up to 1300 degree centigrade.
Solar thermal is heat generated by letting the rays of the sun fall directly on a vessel or on a group of zig-zag copper pipes. To increase the effect of the sun and increase the heat you may paint the pipe black. You could also use a lens so that the sun’s rays converge at a single point thereby increase its heat intensity.
Indirect Solar Thermal
But what if the sunlight is not sufficient? Then you could use a plain mirror, group of mirrors, concave mirror or a group of concave mirrors to focus the sunrays to converge on a single point. The heat generated thus at that point could be very great… sometimes up to 1300 degree centigrade.
What to do with Heat:
The heat thus generated is primarily used to heat water to such an extent that it will keep producing steam and this steam’s force will be used to turn the turbine to produce electricity. This type of systems can generate electricity to power even Air conditioners. This type of technology can also be used to create steam even when the sun is not shining.
How to produce heat during the night?
To keep producing the electricity at night one has to keep producing the steam at night. But since the Sun is not available during the night we have to store the heat produced during day time to be useable at night time. Thus the excess Heat generated during day time is stored into a heat holding tank by way of a heat-transfer fluid that flows into the tank. This tank is well insulated to store the heat.
Abengoa, a renewable energy firm based in Spain, has already built several solar plants that store excess energy in molten salt, which can absorb extremely high temperatures without changing state. Abengoa recently secured yet another contract to build a salt-based 110 mega-watt solar storage plant in Chile, which should be able to store 17 hours of energy in reserve.
There are different kind of heat-transfer fluid but the best of them is molten salt which turns into liquid at around 200 degrees Centigrade. The rate of it loosing the heat is about 1% in a day. Thus steam can be generated even if the sun is not out for days together.
The solar collectors absorb the sun’s rays, convert them to heat and transfer the heat to a heat-transfer fluid. The heat-transfer fluid is then pumped into a heat exchanger located inside the water storage tank where it heats the water.
The heat thus generated is primarily used to heat water to such an extent that it will keep producing steam and this steam’s force will be used to turn the turbine to produce electricity. This type of systems can generate electricity to power even Air conditioners. This type of technology can also be used to create steam even when the sun is not shining.
How to produce heat during the night?
To keep producing the electricity at night one has to keep producing the steam at night. But since the Sun is not available during the night we have to store the heat produced during day time to be useable at night time. Thus the excess Heat generated during day time is stored into a heat holding tank by way of a heat-transfer fluid that flows into the tank. This tank is well insulated to store the heat.
Abengoa, a renewable energy firm based in Spain, has already built several solar plants that store excess energy in molten salt, which can absorb extremely high temperatures without changing state. Abengoa recently secured yet another contract to build a salt-based 110 mega-watt solar storage plant in Chile, which should be able to store 17 hours of energy in reserve.
There are different kind of heat-transfer fluid but the best of them is molten salt which turns into liquid at around 200 degrees Centigrade. The rate of it loosing the heat is about 1% in a day. Thus steam can be generated even if the sun is not out for days together.
The solar collectors absorb the sun’s rays, convert them to heat and transfer the heat to a heat-transfer fluid. The heat-transfer fluid is then pumped into a heat exchanger located inside the water storage tank where it heats the water.
After releasing its heat via the heat exchanger, the heat-transfer fluid flows back to the collectors to be reheated. The controller keeps the heat-transfer fluid circulating whenever there is heat available in the solar collectors. In the winter, a boiler serves as an alternate heat source. Solar thermal systems can be integrated into existing hot water systems with relative ease.
What are the Costs related to setting up Solar Thermal Power Plant:
As of 9 September 2009, the cost of building a CSP station was typically about US$2.50 to $4 per watt, while the fuel (the sun's radiation) is free. Thus a 250 MW CSP station would have cost $600–1000 million to build. That works out to $0.12 to 0.18 USD/kWh.
New CSP stations may be economically competitive with fossil fuels.
CSP studies shows that the cost of both building and operation of CSP plants. Costs are expected to decrease, but there are insufficient installations to clearly establish the learning curve. As of March 2012, there were 1.9 GW of CSP installed, with 1.8 GW of that being parabolic trough.
As of 9 September 2009, the cost of building a CSP station was typically about US$2.50 to $4 per watt, while the fuel (the sun's radiation) is free. Thus a 250 MW CSP station would have cost $600–1000 million to build. That works out to $0.12 to 0.18 USD/kWh.
New CSP stations may be economically competitive with fossil fuels.
CSP studies shows that the cost of both building and operation of CSP plants. Costs are expected to decrease, but there are insufficient installations to clearly establish the learning curve. As of March 2012, there were 1.9 GW of CSP installed, with 1.8 GW of that being parabolic trough.
The solar thermal power industry grew about 1.17 gigawatts (GW) of concentrating solar power (CSP) plants online as of 2011. Spain is by default the leader in this segment with a number of installations.
- About 582 megawatts of them are located in Spain, and
- United States Ranks has 507 MW of capacity, with about 17 GW of CSP projects are under development.
- Spain ranks second with 4.46 GW in development, followed by China with 2.5 GW.
- India too has planned almost a GW of installation.
The best thing about these concentrated power plants are that they are very quick to mushroom so most of the time the figures mentioned are wrong especially if they are more than a year old and you can be sure that the installations are almost double the number in progress and most of these projects can easily be planned, installed and commissioned all within one year.
GGEL has deployed parabolic trough CSP technology with state of the art SKAL-ET 150 trough structure in constructing this 50-MW power plant located near the Nokh Village in Jaisalmer district of Rajasthan, India. The electricity produced at the plant could be used to light around 2.5 million homes in the country with clean energy.
India’s ambitious JNNSM programme aims to install 20,000 MW of solar power capacity in the country by 2022, which includes both solar PV and CSP technologies. While solar PV has been the primary reason for installing over 1.7GW of solar energy in the country, CSP has faltered. Now, with the country’s first CSP plant under JNNSM being commissioned it is believed that other projects may also see the light of the day soon.
GGEL has deployed parabolic trough CSP technology with state of the art SKAL-ET 150 trough structure in constructing this 50-MW power plant located near the Nokh Village in Jaisalmer district of Rajasthan, India. The electricity produced at the plant could be used to light around 2.5 million homes in the country with clean energy.
India’s ambitious JNNSM programme aims to install 20,000 MW of solar power capacity in the country by 2022, which includes both solar PV and CSP technologies. While solar PV has been the primary reason for installing over 1.7GW of solar energy in the country, CSP has faltered. Now, with the country’s first CSP plant under JNNSM being commissioned it is believed that other projects may also see the light of the day soon.
Very large scale solar power plants
There are several proposals for gigawatt size, very large scale solar power plants. They include:
The gigawatt size projects are arrays of single plants. The largest single plant in operation is 80 MW (SEGS VIII and SEGS IX) and the largest single plant in construction is 370 MW (Ivanpah Solar). In 2012, the BLM made available 97,921,069 acres of land in the southwestern United States for solar projects, enough for between 10,000 and 20,000 gigawatts.
There are several proposals for gigawatt size, very large scale solar power plants. They include:
- Euro-Mediterranean Desertec proposal,
- Project Helios in Greece (10 Gigawatt), and
- Ordos (2 Gigawatt) in China.
The gigawatt size projects are arrays of single plants. The largest single plant in operation is 80 MW (SEGS VIII and SEGS IX) and the largest single plant in construction is 370 MW (Ivanpah Solar). In 2012, the BLM made available 97,921,069 acres of land in the southwestern United States for solar projects, enough for between 10,000 and 20,000 gigawatts.
The Future:
A study done by Greenpeace found that concentrated solar power could account for up to 25% of the world's energy needs by 2050.
The increase in investment would be from 2 billion euros worldwide to 92.5 billion euros in that time period. Spain is the leader in concentrated solar power technology, with more than 50 government-approved projects in the works. Also, it exports its technology, further increasing the technology's stake in energy worldwide.
Also since these types of easy, cheap and secure technology is available there is no point in building nuclear power plants that are expensive and also dangerous for those residing for miles near them.
A study done by Greenpeace found that concentrated solar power could account for up to 25% of the world's energy needs by 2050.
The increase in investment would be from 2 billion euros worldwide to 92.5 billion euros in that time period. Spain is the leader in concentrated solar power technology, with more than 50 government-approved projects in the works. Also, it exports its technology, further increasing the technology's stake in energy worldwide.
Also since these types of easy, cheap and secure technology is available there is no point in building nuclear power plants that are expensive and also dangerous for those residing for miles near them.