Solar Energy

Technologies

a) GENERAL

Solar energy is the most abundant & cleanest energy resource on earth. The amount of solar energy that hits the earth’s surface in an hour is almost the same as the amount required by all human activities in a year. Solar energy can be used mainly in three ways one is direct conversion of sunlight into electricity through PV cells, the two others being concentrating solar power (CSP) and solar thermal collectors for heating and cooling (SHC). India is endowed with abundant solar energy, which is capable of producing 5,000 trillion kilowatts of clean energy. Country is blessed with around 300 sunny days in a year and solar insolation of 4-7kWh per Sq. m per day. If this energy is harnessed efficiently, it can easily reduce our energy deficit scenario and that to with no carbon emission. Many States in India have already recognized and identified solar energy potential and other are lined up to meet their growing energy needs with clean and everlasting solar energy. In near future Solar energy will have a huge role to play in meeting India’s energy demand.

b) SOLAR PV TECHNOLOGY

Solar Photovoltaic (PV) cells convert solar light directly to electricity .Photovoltaic can literally be translated as light-electricity.; Crystalline Silicon

Crystalline silicon (c-Si) is the oldest technology for solar PV modules. C-Si modules are subdivided in two main categories: i) single crystalline (SC-Si) and ii) multi-crystalline (mc-Si). Thin Film

A thin film is a newer technology in comparison to the crystalline silicon. They are subdivided into three main families: i) amorphous (a-Si) and micro morph silicon (a-Si/µc-Si), ii) Cadmium-Telluride (CdTe), and iii) Copper-Indium-Diselenide (CIS) and Copper-Indium- Gallium-Diselenide (CIGS).Emerging technologies encompass advanced thin films and organic cells. The latter are about to enter the market via niche applications.

Concentrator technologies (CPV)

Concentrator technologies (CPV) use an optical concentrator system which focuses solar radiation onto a small high- efficiency cell. CPV technology is currently being tested in pilot applications. Novel PV concepts aim at achieving ultra-high efficiency solar cells via advanced materials and new conversion concepts and processes. They are currently the subject of basic research.

c) Solar thermal Technology

Solar energy is used as heat source for heating purposes for direct use and to generate steam for generating electricity through turbines.

Different technologies for solar thermal power plants making use of concentrating solar energy systems are:

i) Parabolic troughs

Parabola has the property of focusing the incoming radiation as its focus. Working on this principle, linear concentrators of parabolic shape are coated with highly reflective material and can be turned in angular movements towards the sun position and concentrate the incoming solar radiation onto a long-line receiving absorber tube. A working fluid is used to transfer the absorbed solar energy, which is then piped to an exchanger or a conventional conversion system. Parabolic trough systems cannot make use of diffused radiation as they use only direct-beam sunlight and require tracking systems to keep them focused toward the sun and are best suited to areas with high direct solar radiation. Most systems are oriented either east-west or north-south with single-axis tracking during the day.

ii) Solar Tower (Central Receiving System)

Central receiver systems use heliostats to track the sun by double axes mechanisms following the azimuth and elevation angles with the purpose to reflect the sunlight from many heliostats oriented around a tower and concentrate it towards a central receiver situated atop the tower. This technology has the advantage of transferring solar energy very efficiently by optical means and of delivering highly concentrated sunlight to one central receiver unit, serving as energy input to the power conversion system. In spite of the elegant design concept and in spite of the future prospects of high concentration and high efficiencies, the central receiver technology require more development for further up scaling plant performance. Its main attraction consists in the prospect of high process temperatures generated by highly concentrated solar radiation to supply energy to the topping cycle of any power conversion system and to feed effective energy storage systems able to cover the demand of modern power conversion systems.

Different receiver heat transfer media that have been successfully used are water/steam, liquid sodium, molten salt, ambient air, oil.

Solar Tower plants have the good long-term perspective for high conversion efficiencies and for use of very efficient energy storage systems by utilization of high temperatures in order to enlarge the solar capacity or solar share.

iii) Linear Fresnel

The Linear Fresnel technology uses long, flat or slightly curved mirrors to focus sunlight onto a linear receiver located at a common focal point of the reflectors. The receiver runs parallel to and above the reflectors and collects the heat to boil water in the tubes, generating high-pressure steam to power the steam turbine (water/direct steam generation, no need for heat exchangers). The reflectors make use of the Fresnel lens effect, which allows for a concentrating mirror with a large aperture and short focal length. This reduces the plant costs since sagged-glass parabolic reflectors are typically much more expensive. Since the optical efficiency as well as the working temperatures are considerably lower than with other CSP concepts, saturated steam conditions have to be considered for this technology. Development is now heading from demonstration plants to bigger, commercialized projects. The receiver is stationary and so fluid couplings are not required (as in troughs and dishes). The mirrors also do not need to support the receiver, so they are structurally simpler. When suitable aiming strategies are used (mirrors aimed at different receivers at different times of day), this can allow a denser packing of mirrors on available land area.

D) Floating Solar :

Floating solar photovoltaic (PV) installations open up new opportunities for scaling up solar generating capacity, especially in countries with high population density and competing uses for available land. They have certain advantages over land-based systems, including utilization of existing electricity transmission infrastructure at hydropower sites, close proximity to demand centers (in the case of water supply reser-voirs), and improved energy yield thanks to the cooling effects of water and the decreased presence of dust. The exact magnitude of these performance advantages has yet to be confirmed by larger installations, across multiple geographies, and over time, but in many cases they may outweigh any increase in capital cost.

The general layout of a floating PV system is similar to that of a land-based PV system, other than the fact that the PV arrays and often the inverters are mounted on a floating platform (figure 1). The direct current (DC) electricity generated by PV modules is gathered by combiner boxes and converted to alternating current (AC) by inverters. For small-scale floating plants close to shore, it is possible to place the inverters on land- that is, just a short distance from the array. Otherwise, both central or string inverters on specially designed floats are typically used. The platform, together with its anchoring and mooring system, is an integral part of any floating PV installation.

Schemes Applicable

The following fund and non-fund based schmes are available in Solar (Ground-Mounted, Rooftop Sectors) :

• Long term Project Financing 
• Short term loan assistance to RE Developers /Suppliers/ Contractors/ Energy Efficiency Projects 
• Bridge loan assistance to RE Promoters/ Developers against Capital Subsidies/VGF
• Guarantee Assistance Scheme to RE Suppliers/ Manufacturers / EPC Contractors/Developers 
• Direct Discounting of MNRE Capital Subsidy for installation of Solar Water Heating Systems 
• Direct Discounting of GBI Claims Payable to Renewable Energy Developers under MNRE Scheme 
• Loan Scheme for Financing Rooftop Solar PV Grid Connected/ Interactive Power Projects
• Credit Enhancement Guarantee Scheme for raising Bonds towards Solar Projects
• Policy for Issue of Letter of Comfort/Letter of Undertaking for opening of Letter of Credit 
• Policy for Financing of Transmission Projects
• IREDA Loan Scheme/Line of Credit for Financing Large Scale Roof Top Solar PV Grid Connected/ Interacted Power Projects.
• Top-Up Loan Scheme 
• Loan against Securitization of Future Cash Flow of Renewable Energy Projects
• Short Term Loan Facility to Govt. Bodies/ Discoms/ Transcos /State Owned Trading Companies
• Loan against Securitization of Future GBI receivables in case of Grid Connected Solar Projects
• Takeover of Term Loans from Banks/FIs and Unsecured Loans/Bridge Loans/Creditors Payables
• Factoring Scheme for purchasing Receivables of Solar Power Developers payable by Eligible Entities

For detailed information on Interest Rate and incentive, kindly refer IREDA's Financing Norms and refer IREDA Website https://www.ireda.in.
IREDA is a financial institution and does not provide any subsidy. For details of Government support/incentives/policy/subsidy available if any, please contact MNRE and refer MNRE website at https://mnre.gov.in/

Procurement Requirements

The borrower is required to follow transparent and competitive bidding procedure for procurement and shall demonstrate that the procurement procedures adopted by them are appropriate to the circumstances and that the quality goods, services and works are purchased at reasonable and competitive prices. The borrower shall provide all such information and documents reasonably required in connection with the procurement of any goods, services and works to be financed by IREDA. Wherever the loan is sanctioned against international lines of credit such as the World Bank, Asian Development Bank, kfW, etc., the relevant procurement procedures stipulated for competitive bidding process will have to be followed by the borrower.

Financial Guidelines and Interest Rate Applicable

For detailed information on  Interest Rate and Incentives to refer IREDA's Financing Norms 

Note : For contacting the Officers working in Solar Group.

List of officers working in Sector- Wind-Solar -Hybrid, Manufacturing,Rooftop Solar, CST Sector