Harnessing Solar energy, Options for India
A study on harnessing solar energy options for India was conducted recently by Shakti Sustainable Energy Foundation, Climate works Foundation and SSN foundation. Supporting this study it has been concluded that solar energy can play a big role in providing electricity to rural areas and thus has been included in India’s rural electrification policy. See more at: http://shaktifoundation.in/report/harnessing-solar-energy-options-for-india/ A study on harnessing solar energy options for India was conducted recently by Shakti Sustainable Energy Foundation, Climate works Foundation and SSN foundation. Supporting this study it has been concluded that solar energy can play a big role in providing electricity to rural areas and thus has been included in India’s rural electrification policy. See more at: http://shaktifoundation.in/report/harnessing-solar-energy-options-for-india/
Factors affecting performance: Temperature: At higher temperatures, the performance of the PV modules drops. Shading: A PV module’s electrical output is extremely sensitive to shading. Dust: Particles of dust and other lint on the surface of the module can absorb sunlight and thus reduce the amount of light that actually strikes the cells. Thus, maintenance of the PV panel is imperative; else the amount of electricity generated will drop. 3. Technology Trade-off Electricity production from solar PV is free of noise and without the release of any toxic substances. However, during the manufacture of solar cells there are varying degrees of technological challenges coupled with issues of efficiency, economy and environmental impact. In this section we discuss the challenges associated with different solar PV technologies. 3.1. Technological Challenges Crystalline silicon solar cells have a large surface area and relatively high conversion efficiency. However, these cells require high inputs during manufacturing (that is, energy and labour) and are heavily dependent on pure solar grade silicon, which has had a limited supply base. In contrast, thin film technology has the advantage in terms of better cost economics for electricity generation; lower material (silicon) usage; and lower energy requirements. However, the land requirement for this technology is higher. 4 Organic PV cells have large band gaps that reduce efficiencies. Both organic and dye-sensitised PV cells have stability issues related to the materials used in production. 5 This problem needs to be resolved before these technologies become viable. The most promising technology is the multijunction cells used in conjunction with CPV. Figure 2: Commercial Module Efficiencies (Source: India Semiconductor Association and National Manufacturing Competitiveness Council, Solar PV Industry: Global and Indian Scenario, 2008, http://nmcc.nic.in/pdf/ISA_NMCC_September2008.pdf, accessed 28 October 2010) 3.2. Efficiency Challenges Cell efficiency has been on the rise, and polycrystalline cells today have an efficiency of 18% and monocrystalline almost 23%. With increasing standardisation of manufacturing equipment and Photovoltaic Technology CSTEP | Page 28
improving efficiencies of modules, it is expected that PV system efficiency will improve in the near term. 6 Figure 2 shows module efficiencies from 1998 to 2008. As is evident, c-Si efficiencies are at 17 to 19% and the thin film efficiencies are at 7 to 11% as of 2008. In research laboratories, multijunction cells combined with light-concentrating optics and sophisticated sun-tracking systems (essentially CPV) have demonstrated the highest sunlight-toelectricity conversion efficiencies of any PV technologies at 41.6%. Other research cell efficiencies range from 20% to almost 28% for c-Si cells; 12% to almost 20% for thin film; and about 5% up to 11% for the emerging PV technologies organic cells and dye-sensitised cells respectively. 7 3.3. Environmental Challenges In terms of toxicity, only low environmental effects are expected for c-Si technologies. However, CdTe and CIS cell technologies are considered more problematic due to their high content of cadmium (Cd), selenium (Se), tellurium (Te) and copper (Cu). In addition, during the manufacture of CIS modules gaseous toxic substances (for example, hydrogen selenide [H 2Se]) may be produced, which are generally associated with a certain environmental hazard potential. The environmental impact of thin film silicon cells is similar to that of the wafer silicon cell, but reduced in magnitude because of the smaller volume of silicon used. On the whole, the environmental effects related to solar cell manufacture are equivalent to those of the overall semiconductor industry. 4. Manufacturing Supply Chain The solar PV industry is one of the fastest growing areas in the energy sector, and over the past few years has seen tremendous growth worldwide. World solar cell production reached 9.34 GW in 2009, up from 6.85 GW a year earlier, with thin film production accounting for 18% of that total. China and Taiwan now account for 49% of global cell production, which reached 3,304 MW in 2008 in these two countries, with Europe at 1,729 MW ahead of Japanese production at 1,172 MW in the same year. 8 India’s annual solar PV module production capacity has reached close to 1 GW or nearly 10% of the global production capacity. However, most of the production is exported. The manufacturing capacity of solar PV modules is expected to grow at a rate of 20 to 25%, and will hit 2.6 GW by 2015. 9 Currently, India does not have the infrastructure for raw material production (polysilicon), and is entirely dependent on imports for the same. However, there are about fifteen players manufacturing around 600 MW of solar cells and over twenty players assembling over 1 GW of modules annually. Furthermore, there are more than fifty players in solar systems integrators. 10 5. Global Policies and Installed Capacities Globally, as of December 2009, the installed capacity of PV was close to 23 GW, which produces about 25 TWh of electricity annually. Just a year prior, in 2008, the installed capacity was just 16 GW. Germany has the maximum installed capacity of 16 GW, followed by Japan (2.6 GW) and the US (1.6 GW). Due to a very generous feed-in tariff, the installed PV capacity in Spain was close to 2.6 GW Photovoltaic Technology CSTEP | Page 29
- Page 3 and 4: Harnessing Solar Energy: Options fo
- Page 5: Foreword Worship the sun god, the L
- Page 8 and 9: 4. ADDITIONAL TARIFF PER UNIT OF EL
- Page 11 and 12: Executive Summary The Jawaharlal Ne
- Page 13 and 14: capital subsidy of `150 per W p pro
- Page 15 and 16: policy choices. A comparison of thi
- Page 17: of PPAs need better clarity. The en
- Page 22 and 23: The Indian power sector is highly d
- Page 24 and 25: 4. Solar Technologies: The Basics T
- Page 26 and 27: Introduction CSTEP | Page 26
- Page 30 and 31: PV Capacity (MW) in 2008; however,
- Page 32: Annual Installed Capacity (GW) 5.5.
- Page 36 and 37: Table 2: Timeline of Indian Policy
- Page 38 and 39: India’s Solar-specific Policies C
- Page 40 and 41: Table 4 gives an overview of JNNSM
- Page 42 and 43: On 16 November 2010, bids from sola
- Page 44 and 45: Table 6: Net Present Value of Outla
- Page 46 and 47: 4.1.3. Policies for Grid-connected
- Page 51 and 52: Cumulative Capacity, Grid Parity an
- Page 53 and 54: Electricity Price (`/kWh) The price
- Page 55: consumed by the customers will grad
- Page 60 and 61: In the case of smaller PV plants, p
- Page 62 and 63: decentralised in that banks and oth
- Page 64 and 65: 1.2.1.Solar Lanterns 1.2.1.1. Overv
- Page 66 and 67: Table 11: Models of Dissemination D
- Page 68 and 69: 1.2.3. Solar PV Microgrid 1.2.3.1.
- Page 70 and 71: NPV of Govt. Subsidies (` in Lakhs)
- Page 72 and 73: Table 12: Capital Cost of Solar-bas
- Page 74 and 75: electrification, assuming a solar s
- Page 76 and 77: electrical energy output of the arr
Factors affecting per<strong>for</strong>mance:<br />
Temperature: At higher temperatures, the per<strong>for</strong>mance of the PV modules drops.<br />
Shading: A PV module’s electrical output is extremely sensitive to shading.<br />
Dust: Particles of dust and other lint on the surface of the module can absorb sunlight<br />
and thus reduce the amount of light that actually strikes the cells. Thus, maintenance of<br />
the PV panel is imperative; else the amount of electricity generated will drop.<br />
3. Technology Trade-off<br />
Electricity production from solar PV is free of noise and without the release of any toxic substances.<br />
However, during the manufacture of solar cells there are varying degrees of technological challenges<br />
coupled with issues of efficiency, economy and environmental impact. In this section we discuss the<br />
challenges associated with different solar PV technologies.<br />
3.1. Technological Challenges<br />
Crystalline silicon solar cells have a large surface area and relatively high conversion efficiency.<br />
However, these cells require high inputs during manufacturing (that is, <strong>energy</strong> and labour) and are<br />
heavily dependent on pure solar grade silicon, which has had a limited supply base. In contrast, thin<br />
film technology has the advantage in terms of better cost economics <strong>for</strong> electricity generation; lower<br />
material (silicon) usage; and lower <strong>energy</strong> requirements. However, the land requirement <strong>for</strong> this<br />
technology is higher. 4 Organic PV cells have large band gaps that reduce efficiencies. Both organic<br />
and dye-sensitised PV cells have stability issues related to the materials used in production. 5 This<br />
problem needs to be resolved be<strong>for</strong>e these technologies become viable. The most promising<br />
technology is the multijunction cells used in conjunction with CPV.<br />
Figure 2: Commercial Module Efficiencies<br />
(Source: <strong>India</strong> Semiconductor Association and National<br />
Manufacturing Competitiveness Council, <strong>Solar</strong> PV Industry: Global and <strong>India</strong>n Scenario,<br />
2008, http://nmcc.nic.in/pdf/ISA_NMCC_September2008.pdf, accessed 28 October 2010)<br />
3.2. Efficiency Challenges<br />
Cell efficiency has been on the rise, and polycrystalline cells today have an efficiency of 18% and<br />
monocrystalline almost 23%. With increasing standardisation of manufacturing equipment and<br />
Photovoltaic Technology CSTEP | Page 28
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