Solar technologies in India: An overview

Parabolic Trough Technology
Source: http://crashell.blogspot.com/2011/02/
solar-thermal-generated-electricity.html
Amid the growing demand for sustainable energy, concentrating solar power (CSP) technologies are on the verge of large scale global deployment. These technologies harness concentrated sunlight to generate electricity. In the coming decade, the CSP market is estimated to be worth over a billion dollars. The Government of India too has identified solar power as an important renewable energy resource and its commitment to develop solar power is reflected in the ‘National Action Plan for Climate Change’ wherein it has announced the ‘National Solar Mission’ as one of the eight missions to combat the challenges of climate change.

Hence, it is important to understand the market readiness of different CSP technologies, the investment opportunities which these technologies are likely to create and the overall market development scenario. TERI was entrusted to undertake a comparative analysis of the different CSP technologies. The study also covered sub-technologies/components which by themselves are an important market segment and also addresses the cost benefit and investment opportunities in solar power projects.

Central Receiver Technology
Source: http://webservices.itcs.umich.edu/drupal/
recd/?q=node/155
The study analysed the market players and overall policy and regulatory situation, the main drivers for the growth of the renewable energy markets in India. The main factors influencing the CSP market in India is the government’s commitment, its budgetary support, and more importantly, availability of funds (grant, debt, equity and low cost finance) from international agencies. Technology development and technology providers’ outlook about Indian market including political and economic stability and bureaucratic hurdles, water, grid, and gas network development in areas of high potential, indigenization of technologies and lowering of costs of equipment and services are other crucial factors.

The government took a major step in promoting solar power in India by announcing the Jawaharlal Nehru National Solar Mission (JNNSM) in November 2009. The objective is to establish India a global leader in solar power generation. The mission also aims to achieve grid parity by 2022 and parity with coal-based thermal power by 2030 and feed 20000 MW of solar power by 2022. While in the first phase (2010-13) it targets 1000 MW of grid-connected solar power, and promotes different decentralized applications including off-grid systems to serve populations without access to commercial energy; in the second (2013-17) and third (2017-22) phases, the power generation capacity will be aggressively ramped up to create conditions for up-scaled and competitive solar energy penetration. Targets include ramping up capacity of grid-connected solar power generation through the solar-specific renewable purchase obligations for utilities, backed with a preferential tariff.

Parabolic dish-sterling engine
Another impetus to the development of CSP technologies came from TERI and the William J Clinton Foundation. They have taken up the initiative to assist the central and state governments in developing an integrated solar power plant facility, appropriately named ‘Solar Park’. A Solar Park is essentially a specially developed area where solar power plant project developers can establish large-scale power plants and/or manufacturing facilities for solar power projects. Typically, a solar park will have the capacity to establish about 3-5 GW capacity power plants. This concept has been well received by the respective state governments and work on land identification and survey is on in Gujarat and Rajasthan, and with that initiative, the Gujarat state government has inaugurated one solar park in Patan district.

Linear Fresnel Reflector (LFR)
Source: http://www.greenrhinoenergy.com/
solar/technologies/cst_technologies.php
The enabling environment created by the various initiatives have led to the development of a variety of CSP technologies like concentrated solar PV (CPV) and concentrated solar thermal (CST). Of these, parabolic trough collectors, power towers or central receivers, compound linear fresnel reflectors, parabolic dishes (dish-sterling engine system) have reached commercialization or are near it.

The parabolic trough technology is currently the most proven CSP technology and, therefore, the most developed and standardized. The parabolic trough projects, currently in operation, are between 14 and 80 MWe in size, and existing plants produce well over 500 MW of electrical capacity.

Central receiver technology is also well proven. Central receiver systems use a field of distributed mirrors i.e. heliostats which individually track the sun and focus the sunlight on the top of a tower. Such systems can achieve up to 35% peak and 25% annual solar electric efficiency when coupled to a combined cycle power plant. Over 300 MW capacity CST power projects have been announced by various companies in the coming decade.

The compact linear fresnel reflector system is similar to the parabolic trough collector system. It consists of an array of nearly-flat reflectors which concentrates solar radiation onto an elevated inverted linear receiver. Water flows through the receiver and is converted into steam. This system is line-concentrating, similar to a parabolic trough, with the advantages of low cost for structural support and reflectors, fixed fluid joints, a receiver separated from the reflector system, and long focal lengths that allow the use of flat mirrors. The technology is seen as a potentially low-cost alternative to trough technology for the production of solar process heat.

The parabolic dish-shaped reflector concentrates sunlight on to a receiver located at the focal point of the dish. The concentrated beam radiation is absorbed into a receiver to heat a fluid or gas (air) to approximately 750°C. This fluid or gas is then used to generate electricity in a small piston or Stirling engine or a micro turbine, attached to the receiver. The dishes are usually designed to track the Sun along two axis to get reflect the sun beam on point of focus.

A cost break-up of the trough and power tower technologies was undertaken. The solar PTC-based solar thermal power plant was estimated to cost Rs 2,02,150/kW and power tower-based solar thermal power plant Rs 2,35,877/kW.

The study also estimated the market for CSP technologies under three scenarios – the solar mission scenario, the optimistic scenario, and the conservative scenario. The solar mission scenario is the result of the government’s policy following the JNNSM. The optimistic scenario is based on the efforts of governments and other initiatives to promote the technologies. The conservative scenario assumes that the development of CSP technology will take place in a sluggish manner. The projected market development indicates that the CSP market can reach about 15.2 GW by 2022 under the optimistic scenario where as under conservative scenario only about 5.7GW market is likely to be developed by 2022. It observed that while the government is taking steps to encourage the development of CSP technologies; much will depend on the implementation of these policies and the impetus from the private sector.

Sponsor: HSBC
Duration: 1 year
Key Stakeholder/Beneficiaries: solar power industries, potential solar power investors, customers
What is concentrated solar power (CSP) technology?

It is a method by which dispersed sunlight is concentrated through the use of low-cost mirrors to generate electricity. This is done in two ways – Concentrating Solar Thermal (CST) and Concentrating Photovoltaic (CPV) technologies.

Conclusions

The concentrated solar power technology is a globally proven technology. India’s vast solar resource potential can be tapped through these technologies for energy generation. There is a need for great focus on the promotion and implementation of these technologies. With the indigenization of the technology, the CSP power generation may soon achieve grid parity.

The findings of the study are:

  • Parabolic trough collector (PTC) will be the most dominating CSP technology by 2020.
  • Maximum Integrated Solar Combined Cycle (ISCC) projects will be of PTC Technology.
  • Parabolic Dish sterling might find space in manufacture of small capacities and no-water design.
  • There are two prime movers of cost reduction of CSP
    • Improvement of efficiencies of the components:
    • i. Reflectors through coatings and new materials;
    • ii. Receivers through new materials of higher optical efficiencies;
    • iii. Tracking and control.
    • Indigenization of various components:
    • i Balance of system of solar field;
    • ii Turbines and boilers;
    • iii Power evacuation system.
  • Low labor costs in India will make the projects financially attractive.
  • Drivers like JNNSM will accelerate the implementation mechanism.
Posted on: 28 December 2011  |   Project status: Completed