Photo-Voltaic power systems
The array of a Photo-Voltaic power system, or PV system, produces direct current (DC) power which fluctuates with the sunlight’s intensity. For practical use this usually requires conversion to certain desired voltages or alternating current (AC), through the use of Inverters. Multiple solar cells are connected inside modules. Modules are wired together to form arrays, then tied to an inverter, which produces power at the desired voltage, and for AC, the desired frequency/phase. Many residential PV systems are connected to the grid wherever available, especially in developed countries with large markets. In these grid-connected PV systems, use of energy storage is optional. In certain applications such as satellites, lighthouses, or in developing countries, batteries or additional power generators are often added as back-ups. Such stand-alone power systems permit operations at night and at other times of limited sunlight.
Solar power in India
India is densely populated and has high solar insolation, an ideal combination for using solar power in India. In the solar energy sector, some large projects have been proposed, and a 35,000 km2 (14,000 sq mi) area of the Thar Desert has been set aside for solar power projects, sufficient to generate 700 to 2,100 GW. In July 2009, India unveiled a US$19 billion plan to produce 20 GW of solar power by 2020 Under the plan, the use of solar-powered equipment and applications would be made compulsory in all government buildings, as well as hospitals and hotels. In January 2015, the Indian government significantly expanded its solar plans, targeting US$100 billion of investment and 100 GW of solar capacity by 2022. According to a 2011 report by BRIDGE TO INDIA and GTM Research, India is facing a perfect storm of factors that will drive solar photovoltaic (PV) adoption at a “furious pace over the next five years and beyond”. The falling prices of PV panels, mostly from China but also from the U.S., has coincided with the growing cost of grid power in India. Government support and ample solar resources have also helped to increase solar adoption, but perhaps the biggest factor has been need. India, “as a growing economy with a surging middle class, is now facing a severe electricity deficit that often runs between 10% and 13% of daily need”.
There are various factors that we need to consider before investing into a solar power plant. A lot of enthusiasm has been seen among people about the use of Solar Energy as a substitute of conventional sources of energy. However, currently, with the power subsidies in India, solar works economical only in those areas that are using diesel generators as a primary source of electricity. The entire payback is made in 2–3 years. Solar system for petrol pumps is a leading example of such an application. IOCL is leading the race for solarisation of petrol pumps with aggressive targets. Solar applications for petrol pumps by Rely On Solar has been installed in more than 150 IOCL petrol pumps across India and now other oil companies are also looking to solarize their ROs. Solar installations for commercial buildings, where the electricity rates are higher, are also proving to be a game changer for the owners of IT companies. On 16 May 2011, India’s first 5 MW of installed capacity solar power project was registered under the Clean Development Mechanism. The project is in Sivagangai Village, Sivaganga district, Tamil Nadu.
With about 300 clear, sunny days in a year, India’s theoretical solar power reception, on only its land area, is about 5,000 trillion kilowatt-hours (kWh) per year (or 5 EWh/yr). The daily average solar energy incident over India varies from 4 to 7 kWh/m2 with about 1,500–2,000 sunshine hours per year (depending upon location), which is far more than current total energy consumption. For example, assuming the efficiency of PV modules were as low as 10%, this would still be a thousand times greater than the domestic electricity demand projected for 2015. The amount of solar energy produced in India in 2007 was less than 1% of the total energy demand. The grid-connected solar power as of December 2010 was merely 10 MW. Government-funded solar energy in India only accounted for approximately 6.4 MW-yrs of power as of 2005. However, India is ranked number one in terms of solar energy production per watt installed, with an insolation of 1,700 to 1,900 kilowatt hours per kilowatt peak (kWh/KWp). 25.1 MW was added in 2010 and 468.3 MW in 2011. By end September 2014, the installed grid connected solar power had increased to 2,766 MW, and India expects to install an additional 10,000 MW by 2017, and a total of 20,000 MW by 2022. 51 Solar Radiation Resource Assessment stations have been installed across India by the Ministry of New and Renewable Energy (MNRE) to monitor the availability of solar energy. Data is collected and reported to the Centre for Wind Energy Technology (C-WET), in order to create a Solar Atlas.
The government of India is promoting the use of solar energy through various strategies. In the latest budget for 2010/11, the government has announced an allocation of 1000 crore towards the Jawaharlal Nehru National Solar Mission and the establishment of a clean energy fund. It is an increase of 380 crore from the previous budget. This new budget has also encouraged private solar companies by reducing customs duty on solar panels by 5% and exempting excise duty on solar photovoltaic panels. This is expected to reduce the cost of a roof-top solar panel installation by 15–20%. The budget also proposed a coal tax of US$1 per metric ton on domestic and imported coal used for power generation. Additionally, the government has initiated a Renewable Energy Certificate (REC) scheme, which is designed to drive investment in low-carbon energy projects.
Net metering, unlike a feed-in tariff, requires only one meter, but it must be bi-directional. In net metering the price of the electricity produced is the same as the price supplied to the consumer, and the consumer is billed on the difference between production and consumption. Net metering can usually be done with no changes to standard electricity meters, which accurately measure power in both directions and automatically report the difference, and because it allows homeowners and businesses to generate electricity at a different time from consumption, effectively using the grid as a giant storage battery. With net metering, deficits are billed each month while surpluses are rolled over to the following month. Best practices call for perpetual roll over of kWh credits. Excess credits upon termination of service are either lost, or paid for at a rate ranging from wholesale to retail rate or above, as can be excess annual credits. In New Jersey, annual excess credits are paid at the wholesale rate, as are left over credits when a customer terminates service.
Feed-in tariffs (FIT)
With feed-in tariffs, the financial burden falls upon the consumer. They reward the number of kilowatt-hours produced over a long period of time, but because the rate is set by the authorities, it may result in perceived overpayment. The price paid per kilowatt-hour under a feed-in tariff exceeds the price of grid electricity. Net metering refers to the case where the price paid by the utility is the same as the price charged.
Timeline of the Jawaharlal Nehru National Solar Mission The Ministry of New and Renewable Energy provides 70 percent subsidy on the installation cost of a solar Photo-Voltaic power plant in North-East states and 30 percentage subsidy on other regions. The detailed outlay of the National Solar Mission highlights various targets set by the government to increase solar energy in the country’s energy portfolio.