Rays of Hope

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.

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/.

Swanson’s Law in action

from https://commons.wikimedia.org/wiki/File:Price_history_of_silicon_PV_cells_since_1977.svg

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.