Figure 1. Solar Energy Potential in Rajasthan [14]
India's energy consumption has been increasing rapidly. Conventional energy resources (coal, gas, petroleum, etc.) are exhaustive in nature. Renewable energy introduces to energy resources that include solar, wind, and geothermal energy that renovate it. Solar energy is the fastest growing energy resources in India. Rajasthan has a massive potential of energy which comes from sun. The atmospheric condition of Rajasthan makes it absolute for efficient solar energy generation. Rajasthan has semi-arid climate. Thar desert covers the 66.67% of complete area of Rajasthan. The climatic condition of Rajasthan causes it suitable to undergo approximately 298-330 bright days per year and 6.1 to 6.5 kwh/m2/sun radiations per day. The average atmospheric temperature of Rajasthan is between 35 to 41 degrees and in summer days, it crosses above 45 degrees. Rajasthan has a potential of producing 100,000 MW of electricity yearly. Till January, 2016, the solar energy generation capacity is of 1264.35 MW which makes Rajasthan first position in India. In this paper, the authors summarize the availability, current status, target, and problems in solar energy in Rajasthan.
Current population of India is 1,336,286,256 (1.3 billion) people (May 2016) which makes India second most populous country in the global [1]. India has an annual population growth rate of 1.2% [3]. Energy resources based on fossil fuels are depleting quickly, where India will suffer a large energy scarcity significantly because of the increase in energy prices and insecurity of energy within the upcoming few decades. Large consumption of conventional resources also effect the environmental cause of pollution. A conventional energy resources (coal, oil and petroleum) satisfied the huge demand for energy, which is non-renewable and hence a nonpersistent solution to the energy disaster that damages the environment. Therefore, it is crucial that India acquires energy security without disturbing the economy, which would denote that India must utilize non-conventional energy resources rather than conventional energy resources which comes from sun in order to reducing conventional fuel demand and hence protect environment against global warming. Solar energy is accepted by earth surface of about 1,20,000 (TW). Solar energy is a sufficient energy resource which satisfy current annual local and global energy consumption demand and also in future energy demand [4]. Most absorbable non-conventional energy sources are the energy of solar as that energy used by humans in a whole year, which is more energy from sunlight received by earth in 1 hour. Energy based on fossil fuel reserve are exhaustive in nature and emits carbon, which cause air pollution and global warming, therefore it is limited by increasing the use of renewable energy resources.
Largest state in India is Rajasthan which covers around 10.6% area (geo-graphical). Nevertheless, the newly found hydro-carbon retained in Rajasthan are limited in nature. There are also restricted accessible nonrenewable sources of energy as fossil fuels (coal, oil, etc.) [14]. Rajasthan has two continual stream, Mahi and Chambal, potential (hydroelectric) of which approximately completely attained. Therefore, Rajasthan experiences two distinctive problems related to generation of power to the non-renewable source. One is there are limited hydropower projects due to nonavailability of large rivers and other one is coal needs to be conveyed from other region of the state, where the transportation alone amounts to 50% cost of energy production [12]. Rajasthan has throughout 208,110 km2 of desert land, which is about 60% of the total land area of the state. Rajasthan has greater than 325 sunny days in a year with solar radiations of approximately 6.0 to 7.0 kwhr/m2/day and in western regions in the Thar desert, it may increase up to 345-355 days as rainfalls only for 10.4- 20.5 days in a year [6, 11]. From Figure 1, it is clearly understood that the annual average solar irradiance incident on various parts of northwestern regions of India in KW/m2/day including Rajasthan state. Table 1 explains the state-wise installed capacity of solar energy potential in India.
Figure 1. Solar Energy Potential in Rajasthan [14]
Table 1. State-wise Installed Capcity of Solar Energy Potential
The western part of Rajasthan has huge amounts of solar energy. Jodhpur district in Rajasthan receives maximum solar radiation intensity, which is well known as Sun City of India. Rajasthan has abundant land so it would be perfect for Photo-Voltaic Array system. Solar energy has huge untapped potential on account of the states, high solar insulation level, the top in India. In Rajasthan, solar industry plays a vital role to the growth of economy, creating jobs and tax revenue along with powering remotely connected households. Jodhpur, Bikaner, Barmer, and Jaisalmer are the pointer regions with best solar radiation in Rajasthan [7]. In Rajasthan, a daily radiation (average) range varies from 5 kwhr/m2 in northern eastern (hilly reasons) and 7 kwhr/m2 in western regions. Moser Bear and Reliance companies have evolved powerplants (solar energy) of 1 to 5 MW each. According to U.S Energy Department, Rajasthan collects the 2nd largest quantity of radiation intensity of solar worldwide. Rajasthan is the prime state in India for generation of power because rainfall (average) is very low. Solar Radiation Intensity in Rajasthan is near to Nevada and California in USA [10] . As by comparing the desert sites of the world, we find that among all the deserts, the Thar Desert in India had received second highest solar radiation in the world as shown in Figure 2.
Figure 2.Comparison of DNI on a Monthly basis for Desert Sites across the Global [9]
Industry of solar energy in Rajasthan is in its initial stage. Yet, the Rajasthan government is motivating investors (private sector) for different Tax and encouragement incentive schemes. These incentive schemes have provided for the solar thermal and solar photo-voltaic systems. State government of Rajasthan has made projects to develop Jaisalmer, Barmer, and Jodhpur as a SEEZ (Solar Energy Enterprises Zone). Power project of solar (140 MW) in Mathania is a landmark in this area, which is India’s first Hybrid Solar Power Project. This project is based on ISCC (Integrated Solar Combined Cycle) Technology, where parabolic trough is used to point sun radiation and after that electricity is generated via turbine. The plant will generate energy of 40 MW, which will cost 1 Million/Megawatt and still lower cost than other technologies like solar photo-voltaic. Nevertheless this projects that some small solar energy based power projects are still working successfully. There are 100 KW capacity power generation system in Jhunjhunu (Gourir) which is first of its type in India, a refrigerator which is powered by solar energy. Jodhpur (Balesar) is the state’s first completely electrified (by solar energy) village in Jaipur.
Two companies (Reliance and Moser Bear) are generating power of 1-5 Megawatts. But power project of Moser Bears will be the biggest solar farm grid connected in the country. Government of Rajasthan has signed a memorandum with Clinton Foundation on January 2010. According to this, the foundation will give technical assistant and mandatory help to setup solar parks of 3000-5000 MW capacities in Rajasthan. Ahead the formation of NSM (National Solar Mission), the state Government has taken a lead in year 2008 and recommends two solar energy projects each of 5 MW under GBI (Generation Based Incentive) Scheme. To give encouragement in solar sector, RERC (Rajasthan Electricity Regulatory Commission) point orders on April 2nd 2008, first time in the country, imposing solar specific RPO (Renewable Procurement Obligation) for Discom in state to encounter RPO needs. The Rajasthan Government approves energy (solar) projects of 11 private companies for establishment of 66 MW generation capabilities employing accessible technologies in Solar Photo-Voltaic and Concentrated Thermal.
After declaration of Jawaharlal Nehru National Solar Mission, the government of state allowed these projects to be migrated to the NSM (National Solar Mission) under the migration scheme of National Solar Mission. There are seven solar power generation plants each generated 5 MW power using photo-voltaic technology have been already commissioned under this mission. The RERC (Rajasthan Electricity Regulatory Commission) has also informed the RERC (REC & RPO complains framework) regulations, on December 23rd, 2010. Further, state electricity regulatory commission has also provided from time to time DRPOs and feed in tariff for renewable energy projects.
MNRE (Ministry of New and Renewable Energy) under solar energy mission selected investors for the development of solar powerplant of (800 MW) capacity under the phase I of National Solar Mission. In ruthless offers, the solar power tariff came in the span of 
11.50 to 12.95 per unit, whereas the cost of energy generated by conventional fuel was about 3 [8].
As Rajasthan has an enormous potential for solar energy growth, it has its own target to product the maximum energy from solar radiation. Target is categorized into two parts, first one is under National Solar Mission and second one under State Solar Policy.
In Table 2 lists the utility grid power generation including rooftop Rajasthan has 1100 MW for commercial year 2013, 400 MW for commercial year 2017 and 20000 MW for commercial year 2022. This becomes 200 MW, 400 MW, and 200 MW for commercial years 2013, 2017, 2022, respectively under off grid Installation. These targets are comparable to 7, 15, and 20 million square meter under solar energy collector [13].
Table 2. Solar Energy Target In Rajasthan
Under new power project (Out of total 1100 MW), Rajasthan finds the largest part of about 874 MW (which is about 79.37%) of total allocation under the phase first of JNNSM (Jawaharlal Nehru National Solar Mission). The priority is because of Geo-Graphical and climate advantage of Rajasthan [5]. Rajasthan is on top in utilization of solar radiation in the generation of power. A number of projects have been installed in western region of Rajasthan mainly in Jodhpur, Jaisalmer, Bikaner, and Barmer and in the remaining parts of the state. The state of Rajasthan has a potential of producing approximately 100,000 MW of electricity yearly. 14th, January, 2016 solar power generation capacity of state is of 1264.35 MW which makes Rajasthan 1st position in India [2].
Rajasthan is an appreciative destination due to high radiation and average atmosphere temperature of Rajasthan is between 35 to 41 degrees and in summer days, it reaches 45 degrees and hence the array soilng losses is high due to the dust and the high temperature photovoltaic losses is very high.
Another problem is the price of solar energy generation versus conventional fuel based sources of energy with high per unit cost and renewable purchase obligations imposition due to which a private solar developer can be disappointed. Grid availability and open access and wheeling charges are also a crucial issue for solar energy project development in the state of Rajasthan. Finally project execution challenges also delays some projects and these challenges are land acquisition and statutory approvals.
The status of Rajasthan has a huge potential to generate solar power. The accessible energy of solar in the state of Rajasthan is 5.9 to 7 kwh/km2 which gives a potential of 10000 MW solar energy commercial generation. Rajasthan has set targets for electricity production from solar energy, which has generated 1300 MW, 50000 MW, and 22000 MW power in commercial years 2013, 2017, and 2022, respectively. Currently, there are many companies working in the field of solar energy development, of which major developers are Dahanu solar power, SEI Solar Power Ltd, Azure Solar Pvt Ltd, Welespur solar AP Pvt Ltd, and Mahindra Suryapraksh Pvt Ltd.
A report published by MNRE show that Rajasthan currently produces 1264.35 MW of electricity from solar energy and this makes Rajasthan first position in India. There are also some problems like soiling losses and temperature losses due the temperature in western part of Rajasthan. Private companies also face some problems like finance, statutory obligations, and Renewable Energy Certificate (REC). There is a crucial need to accelerate the solar power generation to achieve its solar power targets.
Finally, the objective of this paper has been explored that includes potential, target, problem of solar energy production in Rajasthan and this paper can also be used as an information tool for investigation scenario of electricity generated by solar energy in Rajasthan.