Indian Government has planned for setting up 100000 MW of solar generating capacity by 2022. To achieve this environment friendly ambitious target auctions are going, MOUs are being finalised to set up solar photovoltaic (PV) power plants in various parts of the country. But one thing which government should give heed to is these PV power plants can work only during day i.e. they can produce electricity only for day not night. Hence Government is also planning to more than double its coal-fired power output by setting up 455 more coal-based power plants by 2030 to meet base load demand. It will nullify the positive impacts of PV power plants by polluting environment. And international community may also impose severe penalties or will not allow on such huge social cost of burning coal---severe air pollution, increased mortality, destruction of the environment and expropriation of the poor from coal-bearing lands.
What can be the solution or alternative to these coal-fired power plants for base load demand? Yes there is, Concentrated solar thermal power (CSP). The benefits of CSP are-
a) CSP plant can provide power day and night.
b) No or very less need of fossil fuel backup hence do not need to be paired up with conventional coal or nuclear power plants.
c) They can store sun's energy for long periods at very little cost, and with negligible loss. This is how they provide power at night too.
d) Another significant advantage is that CSP plants can produce steam at well above 593 degree celsius required for supercritical power stations and can, therefore, be used with the same ultramodern turbines that are being used in our ultra-mega power plants.
This is totally a viable propostion as already 61 operational solar thermal power plants are in the world with generating capacity of 4228 MW. This became possible when Gemasolar a 20 MW power plant established in spain in 2011. Specifications of Gemasolar are-
a) It can store 6500 hours of power a year i.e. 10% more than coal fired power plants generate in India.
b) Gemasolar stores 15 hours of extra heat during the daytime to run the turbines at night and in bad weather.
c) Because of extra storage it keeps only 15% backup of natural gas to guarantee power on demand, overall cheaper than PV.
But this does not mean that all solar power plants should be CSP as cheapness can be deceptive too. For example a place like thar desert most viable for solar energy production have two complications-
a) PV panels lose half a percent of their efficiency for every degree of temperature rise above ambient levels. This amounts to a 2% fall in delivered power for every extra degree of heat.
b) PV power also needs to be stepped up to grid voltages. This increases the cost of transimission by up to three times.
Hence this target of 100000 MW target needs to be divided into two sections to utilise the resources properly and provide power under the cost for both day and night-
a) reserves the bulk of the extra-capacity solar thermal power generaion
b) issues separte tenders for each part.
What can be the solution or alternative to these coal-fired power plants for base load demand? Yes there is, Concentrated solar thermal power (CSP). The benefits of CSP are-
a) CSP plant can provide power day and night.
b) No or very less need of fossil fuel backup hence do not need to be paired up with conventional coal or nuclear power plants.
c) They can store sun's energy for long periods at very little cost, and with negligible loss. This is how they provide power at night too.
d) Another significant advantage is that CSP plants can produce steam at well above 593 degree celsius required for supercritical power stations and can, therefore, be used with the same ultramodern turbines that are being used in our ultra-mega power plants.
This is totally a viable propostion as already 61 operational solar thermal power plants are in the world with generating capacity of 4228 MW. This became possible when Gemasolar a 20 MW power plant established in spain in 2011. Specifications of Gemasolar are-
a) It can store 6500 hours of power a year i.e. 10% more than coal fired power plants generate in India.
b) Gemasolar stores 15 hours of extra heat during the daytime to run the turbines at night and in bad weather.
c) Because of extra storage it keeps only 15% backup of natural gas to guarantee power on demand, overall cheaper than PV.
But this does not mean that all solar power plants should be CSP as cheapness can be deceptive too. For example a place like thar desert most viable for solar energy production have two complications-
a) PV panels lose half a percent of their efficiency for every degree of temperature rise above ambient levels. This amounts to a 2% fall in delivered power for every extra degree of heat.
b) PV power also needs to be stepped up to grid voltages. This increases the cost of transimission by up to three times.
Hence this target of 100000 MW target needs to be divided into two sections to utilise the resources properly and provide power under the cost for both day and night-
a) reserves the bulk of the extra-capacity solar thermal power generaion
b) issues separte tenders for each part.
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