A Comprehensive Overview of Renewable Energy Status in India - Environmental Sustainability: Role of Green Technologies - page 90

incorporated CASE, was created in the Ministry of
Energy. In 1992, DNES became the Ministry of
Non-conventional Energy Sources (MNES), the
world's fi rst ministry committed to renewable
energy. In October 2006, the ministry was rechris-
tened as the Ministry of New and Renewable
Energy ( MNRE ) ( www.mnre.gov.in ) . Indian gov-
ernment policy framework in renewable energy
generation is extremely investor friendly, and an
attractive tariff and regulatory regime provide a
strong foundation for the growth of the sector.

global radiation is received in Rajasthan, north-
ern Gujarat, and parts of Ladakh region, the parts
of Andhra Pradesh, Maharashtra, and Madhya
Pradesh also receive fairly large amounts of radi-
ation as compared to many parts of the world
especially Japan, Europe, and the USA where
development and deployment of solar technolo-
gies is maximum (Garud and Purohit 2009 ).
Solar power is the generation of electricity
from sunlight. This can be direct as with photo-
voltaics (PV) or indirect as with concentrating
solar power (CSP), where the sun's energy is
focused to boil water which is then used to pro-
vide power (Sharma 2011 ). Since solar radiation
is intermittent, solar power generation is com-
bined either with storage or other energy sources
to provide continuous power.
Concentrating solar power (CSP) systems use
lenses or mirrors and tracking systems to focus a
large area of sunlight into a small beam. The con-
centrated heat is then used as a heat source for a
conventional power plant. A wide range of con-
centrating technologies exists; the most devel-
oped are the parabolic trough, the concentrating
linear Fresnel refl ector, the Stirling dish, and the
solar power tower. Various techniques are used to
track the sun and focus light. In all of these sys-
tems, a working fl uid is heated by the concen-
trated sunlight and is then used for power
generation or energy storage (Martin and
Goswami 2005 ). Concentrated solar power sys-
tems can be used for a range of applications
depending upon the energy conversion utilized,
electricity or heat. However, at present, most sys-
tems focus on electricity generation. The para-
bolic trough collector is the best solution for
applications in the low temperature ranges such
as detoxifi cation, liquid waste recycling, and
heating water. All three systems are suitable for
the mid-temperature range applications, and the
central tower is the most suitable for high tem-
perature range system because temperatures of
more than 1,000 °C can be easily sustained.
Since solar power is at the introductory stage
of its life cycle, Indian government initiatives are
expected to drive it until 2012. The Government
of India realizing the need for alternate sources of
energy other than coal and oil has introduced

2.1 Solar Energy

Solar energy is the most abundant permanent
energy resource on earth, and it is available for
use in its direct (solar radiation) and indirect
(wind, biomass, hydro, ocean, etc.) forms. Solar
energy, experienced by us as heat and light, can
be used through two routes: thermal route or the
photovoltaic (PV) route. The thermal route uses
the heat for water heating, cooking, drying, water
purifi cation, and power generation. The photo-
voltaic route converts the light in solar energy
into electricity; it can be used for applications
such as lighting, pumping, communications, and
electrifi cation of villages.
India lies in the sunny belt of the world. The
scope for generating power and thermal applica-
tions using solar energy is huge. Most parts of
India get 300 days of sunshine a year, which
makes the country a very promising place for
solar energy utilization (TERI 2001 ). The daily
average solar energy incident over India varies
from 4 to 7 kWh/m 2 with the sunshine hours
ranging between 2,300 and 3,200 per year,
depending upon location (MNES 2001 ). The
technical potential of solar energy in India is
huge. The country receives enough solar energy
to generate more than 500,000 TWh per year of
electricity, assuming 10 % conversion effi ciency
for PV modules. It is three orders of magnitude
greater than the likely electricity demand for
India by the year 2015 (Muneer et al. 2005 ).
Figure 1 shows a map of India with solar radia-
tion levels in different parts of the country. It can
be observed that although the highest annual