Environmentalists are often jeered as
doomsayers and also branded as anti-development. But search for renewable energy
technology could not get the boost as it got without the constant thrust from
the green side of the opinion spectrum.
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| India's Solar Thermal Journey in 2013-2014 |
One of the most abundant renewable energy
sources is the Sun, which is incidentally, the ultimate source of energy of
earth. Though there is the problem of intermittence, it is unavailable at
night, always changing, and also unpredictable at places for some time due to
cloud, fog, mist, rain or snow and etcetera. But due to a long history of
observation we already can predict availability of solar energy at different
latitudes and longitudes with much precision. For India IISC researchers have
developed and submitted detail block by block mapping of this availability (Block
is the lowest administrative area, also called Mandal in Hindi) and sent it to the
state governments. The scientific paper is available too — Hotspots of solar
potential in India, at http://wgbis.ces.iisc.ernet.in/energy/paper/hotspots_solar_potential/.
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Swanson’s Law in action
from
https://commons.wikimedia.org/wiki/File:Price_history_of_silicon_PV_cells_since_1977.svg
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Solar energy can be converted to electrical
energy, which is the energy form most suitable for transmitting at distances. Broadly
speaking there are two ways: One is the more known solar photovoltaic energy,
converts solar energy to electrical energy by photo electric conversion. The
second is the less discussed Solar Thermal Energy.
Solar PV (photovoltaic) energy system is
becoming cheaper and more efficient day by day. One scientist from Stanford,
Professor Richard Swanson developed his Swanson’s Law which states: solar cell
prices decline by 20% for every doubling of solar panel industry capacity.
Solar panels becoming cheaper means cheaper solar electricity, and Solar Power
is gaining “Grid Parity” in many countries, starting with Germany in 2011-12. Deutsche
Bank is predicting Solar gaining Grid Parity in most countries by 2017. A Deutsche
Bank study is available at https://www.db.com/cr/en/concrete-deutsche-bank-report-solar-grid-parity-in-a-low-oil-price-era.htm
which predicts this even in a low-oil-price scenario. So solar is a market proposition
now, no more a green or elitist Haute Couture.
Archimedes talked about using concentrated
solar power as a war weapon some 2230 years ago (in 214–212 BC). Solar Thermal Power
plants are at work in Spain and France since long. The famous Planta Solar 10
(PS10) plant in Spain is the world's first commercial concentrating solar
power (generating since 2007) tower at Seville that gives 11 MW power. It produces superheated
steam at 50 bar pressure at about 275-300⁰C. Energy conversion efficiency is on the
rise since that time. A French Solar Furnace was able to reach 3500⁰C by concentrating the
rays of sun as early as in 1970.
Presently there are four main types of
solar thermal technology available: (1) Parabolic Trough; (2) Linear Fresnel;
(3) Dish Engine and (4) Power Tower (for example, see http://www.seia.org/policy/solar-technology/concentrating-solar-power).
Of course there are some glitches. For concentrated
solar systems we can site most obvious three. (1) If birds or anything alse
come in the way of the Archimedean death rays, it will be burnt down instantly.
(2) It takes up large land area – so we need to calculate MW/Hectare and keep
that in mind. If we use an area for solar thermal, most possibly we are NOT
using that area for vegetation (green cover). (3) Most sunny areas are water
scarce, particularly in case of India, Rajasthan is and so also is Gujarat. We should be vigilant at NOT losing the water
used for steam generation for power; we are to recycle the water as much as
possible.
Nevertheless, we can perhaps safely say
that we are witnessing rays of hope in renewable energy technology sector.
So, next time you travel to Jaisalmer, you
may find more places of attraction than just the Sonar Quila or Golden
Fort.
