I have been long thinking whether the vast solar energy that is wasted in the tropical regions can in any way be utilised. Of course trees consume solar energy. But is there no other way of directly utilising the radiant energy of the Sun? -Excerpt from the personal diary of Acharya Jagadish Chandra Bose (Sunday, 5 March 1885)
Acharya JC Bose is recognised the world over as a pioneer in the science of Millmetre waves, using galena (lead sulphide) semiconductor detectors called coherers. Averse to patenting, his only US patent in 1904 was through the intervention of Sister Nivedita. It is not generally known that he did not rest on his words but also invented a ‘Tejometer’-a prototype solar cell using galena as the semiconductor.
Over a 100 years later India has woken up to the importance of solar energy in its development mission. The Jawaharlal Nehru Mission (JNM) for solar energy initially proposed to install 20,000 MW (20 GW) of solar photovoltaic systems by 2020. The target has been increased to 100,000 MW by 2022, a challenging proposition to say the least. Use of renewables such as solar energy is a major weapon against global warming as there are no fossil fuels involved except in the manufacture of the systems. The intensity of solar radiation varies depending on the location, is subject to the vagaries of the weather, and is not available at night. Nevertheless, it has been shown that villages at a distance of 15 km from the grid are best served by stand-alone solar installations. As such, with other renewables such as micro-hydel and biomass, it is the best solution for supplying electricity to 30 per cent of India’s villages that still remain without electricity. JNM’s aim is to ensure ‘domestic production of critical raw materials, components and products, as a result to achieve grid tariff parity by 2022’. Herein lies the problem.
The Prime Minister is fully aware of the importance and relevance of solar energy. It appears that India has forged a "solar alliance" with France which gets over 70 per cent electricity from nuclear plants and is not specially advanced in solar PV though it was the first to install a solar tower for solar thermal power generation. Germany being the most advanced country in Europe with up to 15 per cent electricity generated from Solar PV, it would have been logical to tie up with that country in a solar mission on his recent visit to Germany.
Silicon is the material at the base of modern electronics and IT, be it computers, television, mobile phones which all depend on silicon chips for their operation. Semiconductor silicon is now used in 85 per cent of all the photovoltaic (PV) cells in commercial use. However in the 21st century when India is vying to become a world power, it does not manufacture even one kilogram of Semiconductor Silicon. The limited manufacture of silicon chips in SCL Chandigarh, BEL and ITI in Bangalore all depend on imported wafers. These are required in limited quantities but when it comes to silicon in photovoltaics it&’s a different matter altogether. One MW capacity of solar modules requires 3-7 tonnes of highly pure semiconductor grade silicon. Thus for 20,000 MW, India requires about 100,000 tonnes of silicon.
China has captured the Solar PV market worldwide and now makes more than 90,000 tonnes annually. Even Taiwan produces 8000 tonnes/year while India depends entirely on imports. In 2013 the production of high purity polysilicon reached 200,000 tonnes worldwide. As for the manufacture of photovoltaic modules, China, starting with one per cent in 2001, now accounts for 45 per cent of world production.
What was the Planning Commission doing in the last two decades? The much-vaunted Solar Mission has nothing to say about this glaring omission. The members of the Science Advisory Committee are mainly nuclear scientists and metallurgical engineers who have been obsessed with the signing of the Indo-US nuclear accord, the import of uranium from Australia and Canada and most recently the import of 2000 tonnes of uranium from Uzbekhistan. On the other hand, Electronics and Renewable Energy has had no strong advocate in the committee.
Obsessed with nuclear energy, India neglected the development of electronics. ECIL in Hyderabad was set up mainly as an auxiliary to the nuclear industry to provide instrumentation and control. Thus the first public sector semiconductor industry to be set up, Bharat Electronics (BEL), started its venture into Germanium transistors in the late 1960s when the rest of the world had already switched over to silicon. The electronics revolution has led to a dramatic improvement in mobile communication. The computer market is expanding at the rate of 30 per cent annually (no thanks to the GOI), but where is the ‘energy too cheap to meter’ promised by nuclear reactors? No more than 4.5 per cent of the electricity generated in India is from nuclear reactors. There is increasing resistance to setting up such reactors after Chernobyl and Fukushima. Since 1000 MW nuclear power reactors require one million gallons of water every day, are our seashores to be dotted with reactors every 100 miles? Decommissioning an early reactor in Britain is estimated to cost $ 20 billion. Are these figures factored in when calculating the cost of nuclear energy? Given an enormous AEC establishment and after investing thousands of crores over six decades, why do we have to look to France, Russia or the USA for technology? Remember Homi Bhaba&’s brave assertion that in future ‘India should not have to look outside for nuclear technology’.
It is not commonly realised that electronic-grade silicon is the purest material on earth. It is like finding a Black Hole among a million million stars. There are now only 6-8 major producers of electronic-grade silicon in the world, Germany, Norway and Taiwan being the other three. All are vigorously expanding their production capacity in view of the worldwide shortage of silicon, which is expected to become even more critical with the rapid expansion of the PV industry, especially in developing economies.
Indigenous production of silicon is essential for making large-scale solar PV projects in India viable. After all there is no fuel, no cooling water requirement and hardly any maintenance costs with round-the-year energy generation. The drawback is obviously the limited hours of sunshine, and this requires battery storage.
However there are many applications such as irrigation and office air-conditioning where the demand is maximum during daylight hours. Solar lighting has already proved to be a boon in villages near the Sunderbans and has transformed lifestyle. Due to wrong planning and excessive reliance on nuclear energy India has again missed the silicon bus. The Prime Minister&’s ambitious ‘Make in India’ project should surely include the manufacture of semiconductor silicon, which is the bedrock of the modern electronics and IT industry.
The writer is a former professor, Indian Institute of Science, Bangalore, and former Dean and Professor, IIT Kharagpur.