How Is Solar Resource Assessment Done?

10.2.1 Solar resource assessment – Solar resource assessment is a necessary step in PV plant design that allows understanding the feasibility of a plant in a given location. One of the ultimate objectives of the assessment is to find out the amount of solar potential that is available and how much energy from a PV power plant with typical PV technology can be annually produced,

1. There are certain factors that vary from place to place and with time, hence it is important to gain knowledge of these factors before establishing.
2. These factors include the solar irradiance at a horizontal plane, the irradiance at a tilted position of the PV module, and a sun path diagram.
3. Solar resource assessment generally involves collecting meteorological data from the site such as weather data, the amount of sunlight received in the location, wind speed, air temperature, etc.

There are two methods in which the assessment is done: Onsite ground measurements and collecting satellite data: Over a lengthy period of time, lasting one to several years, a variety of sensors are used such as pyranometers to measure solar irradiance at the location,

• Secondary or primary data from satellites: The second method involves studying obtained secondary or primary data from satellites, such as statistically aggregated solar data, to conduct the SRA.
• The SRA is merely the feasibility study.
• There are a variety of other factors to consider in order to optimize the yield of a solar power plant,

The solar resource assessment potential would vary from location to location. Here, in Fig.10.2 we show how global horizontal solar irradiance varies across the globe. The solar resource map below reveals that the long-term average of global horizontal irradiation varies from 2.2 to 7.4 kWh/m 2 /day worldwide. Fig.10.2, Solar resource potential map, Also, the related PV potential is shown in Fig.10.3, With the use of specific PV technology, the maximum possible PV energy varies from 2 to 6.4 kWh/KWp on a daily basis. The yearly PV potential would vary from 730 to 2337 kWh/kWp. Fig.10.3, PV power potential map, Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780128196106000107

How do you test a solar panel performance?

Step 3: Look at the inverter – is there a red or green light? – Many solar owners never go near their inverter, but CHOICE found that 20% of surveyed solar owners had experienced problems with it. How would you know if there’s a problem? A simple health check is to look at the colour of the lights shining on the box during daylight hours when the system’s meant to be running.

• A green light on your inverter means your system is functioning properly.
• A red or orange light during daylight hours means there’s a system event or fault.
• In the event of a red or orange flashing flight, look for an error code on the display.
• Alternatively, you may be able to go to the inverter’s user interface via a web portal for an indication of the cause.

Finn Peacock from Solar Quotes says, “If there’s an error message, call the installer.” Inverters can shut down due to a grid fault where the voltage is too high or too low, or there may be a problem with the earthing of the system. Another reason might be that the circuit breaker for the inverter has tripped.

How do you monitor solar production?

Welcome to Solar System Monitoring – Now, many solar systems come with monitoring capabilities. This allows home and business owners to analyze solar panel output, with both real-time and historical data. In many cases, information on each solar panel’s output is available, making it easy to pinpoint and troubleshoot problems.

Monitoring helps determine if the equipment is running properly, allowing solar technicians to identify and troubleshoot issues. There are a variety of solar monitoring systems, and most are associated with solar inverters. Common brands of solar inverters include Fronius, SolarEdge, SMA America, Enphase Energy, and Tigo Energy,

Each of these companies typically offers proprietary monitoring software that integrates with their inverters. Another option is a plug-in that adds monitoring capabilities to your existing solar system. Sense, for example, makes a solar monitoring tool that plugs into a Wi-Fi network to track solar power production and your energy use.

How many solar assessment Centres in India are?

Solar radiation varies throughout the day. As such it is very important that precise measurement of solar rays is done to design, develop, and analyze the performance of solar power plants. A continuous spatial estimate using a satellite can be done, but the best data collection is done using ground-based measurement instruments. To meet the target MNRE is setting up a network of 115 automatic solar and meteorological measuring stations called Solar Radiation Resource Assessment (SRRA) Stations. The Centre for Wind Energy Technology (C-WET), Chennai, has started a SRRA Unit on mission mode and all 115 SRRA stations were completed in two phases.4 Advanced Measurement Stations (AMS) with additional sensors are equipped to study effects of suspended particulate matter (turbidity/aerosol concentration) in atmosphere, water vapor, gases, dust particles etc., on scattering or absorption of solar irradiance have been installed at National Institute of Solar Energy (NISE), Gurgaon, Indian Institute of Engineering Science and Technology (IIEST) – Howrah, Pandit Deendayal Petroleum University (PDPU), Gandhi Nagar and Prathyusha Institute of Technology and Management (PITAM), Tiruvallur.

Each of these AMS provide non-stop info on aerosol column, column ozone, atmospheric turbidity, water vapor and NOx in atmosphere.10 independent narrow wavelength channels between 300 to 1020 nm are constantly monitored for use in UV spectrum analysis. The AMS was set up for quantification of attenuation of solar radiation due to the presence of aerosols in atmosphere and also for measuring the reflectivity of earth (Albedo), atmospheric visibility and incoming long wave radiation for research and development purpose.

GIZ, Germany is providing technical assistance to maintain high quality standards on quality measurement, report generation, checks, and Solar Atlas of India. What is SRRA SRRA is a large-scale networked project spread across 121 ground stations that involves measurement and collection of data from SRRA stations spread across India under Phase-I & Phase-II program which is archived at the CRS of C-WET. A typical SRRA station consists of two towers of 1.5 m and 6 m height.

The 1.5-m tall tower houses a solar tracker equipped with pyranometer, pyranometer with shading disc, and a pyrheliometer to measure global, diffuse, and direct radiation, respectively. The 6-meter tall tower houses equipment to measure temperature, humidity, atmospheric pressure, wind speed, direction, rain gauge and data acquisition system.

All sensors meet World Meteorological Organization (WMO) and World Radiometric Reference (WRR) standards. The Sun Tracker is configured using GPS system that is always facing the sun. Each of the SRRA station is equipped with equipment/sensors for measuring Global Horizontal Irradiance (GHI), Direct Normal Irradiance (DNI), Diffuse Horizontal Irradiance (DHI), wind speed & direction, relative humidity, ambient temperature, rainfall and atmospheric pressure.

Each SRRA station located mostly at technological universities and engineering colleges across India are powered by a photovoltaic panel with upto 7-day autonomy. The Data Acquisition System records 37 measured and derived parameters each second and transmits data after averaging it to 1 minute directly to the Central Receiving Station (CRS) set up at C-WET.

In case of any failure in connectivity, built-in provision has been made to store data for upto 6 months in memory chip, that can be retrieved when needed. A completely automatic quality control procedure is implemented in data processing, analysis and report generation.

This includes flagging and gap filling methods using quality check algorithms that directly applies on the raw data. A dedicated Level 2 server installed at C-WET for applying algorithms specifically developed for data analysis and quality checks based on the raw data collected. For values of Direct Normal Irradiance (DNI), Global Horizontal Irradiance (GHI), and Diffuse Horizontal Irradiance (DHI); applied quality control is based on Baseline Surface Radiation Network (BSRN) rules of World Meteorological Organization (WMO), and elaborated by Management and Exploitation of Solar Resource Knowledge (MESOR).

Data on pyrheliometer error %, azimuth angles, solar elevation, battery voltage and signals on sensor cleaning status are also collected at CRS, C-WET, Chennai. A trigger switch installed track the cleani0ng status of each SRRA stations on daily basis.

• Reports are generated on daily/monthly/yearly basis once quality assessment has been done.
• The collection and display of data is done by a specially designed software.
• Data is monitored in CRS both numerical and graphical format.
• The collected data is available for use by the solar developers, academics and research and development institutions on payment basis; as per policies of Solar Data Sharing and Policy (SDSAP-2013) of MNRE.

Why Measurement Under SRRA Necessary

1. Ground measured data is usually more accurate.
2. Quantification of the ground data is possible.
3. A combination of measured and satellite data helps better understand the solar potential area.
4. Helps in preparation of accurate and reliable SOLMAPS.
5. Helps develop & design performance parameters.
6. Helps determine the bankability of the solar power proposals.

How SRRA Sites Were Selected Even though mostly research institutes/academic centers were chosen for installing SRRA stations; but the criteria for selection was as follows:-

1. Area
2. Free horizon
3. Strong network connectivity
4. Safety & Security
5. Electromagnetic interference
6. Easy accessibility to site

How SRRA Works

• The server at CRS went operational on May, 2011.
• The data is transferred from SRRA stations to CRS, Chennai ever since.
• To ensure quality and accuracy of data transmitted to CRS at C-WET, Chennai it is extremely important to maintain the health of each station by properly monitoring them on daily basis.
• As many of SRRA stations are installed in remote areas, the role and commitment of station keepers in upkeep and safety of the instruments and sensors is important.
• The quality of data depends on accuracy and daily maintenance levels of sensors used for measurement. However over time the sensor accuracy levels are bound to change forcing re-calibrations of sensors as per international standard protocol.
• A calibration laboratory at C-WET calibrate field sensors once every two years. The primary standard instruments are to be calibrated against WRR standards at Geneva, Switzerland once in 4 years.
• A specific document has been prepared for calibration as per Indian conditions based on ISO:9847, ISO:9846 and ISO:9059 guidelines.

ICI Collaboration for SRRA The SRRA project works in synergy with SolMap project, funded by International Climate Initiative (ICI) of Federal German Ministry of Environment, Nature Conservation and Nuclear Safety. SolMap is implemented by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) in co-operation with MNRE.

GIZ provides SRRA with technical assistance and capacity building at C-WET that helps the concerned people to maintain desirable standards on quality, checks, report generation. GIZ also supports C-WET in carrying out scientific data analysis as well as generation of value added products. C-WET is also collaborating with other national and international Institutes like Space Application Centre, Ahmadabad; National Renewable Energy Laboratory, USA.

Indian Solar Radiation Atlas The atlas was launched on 3 June 2015 by National Institute of Wind Energy (NIWE), as an online GIS-based information portal to facilitate expansion of the solar energy sector in India. NIWE is a research institute under MNRE. SolMap Project was the harbinger for setting up Solar Radiation Measuring Network and later morphed into the development of this Atlas. Implementation of National Solar Mission Government Incentives As of the end of July 2015, following are the 5 most prominent incentives:-

Accelerated Depreciation: For profit making enterprises who install rooftop solar systems upto 40% of investment can be claimed as depreciation in the 1 st year itself significantly decreasing tax to be paid in Year 1 for profit making companies.

Capital Subsidies: Capital subsidies are applicable to rooftop solar power plants, up to 500 kW. While the original capital subsidy was 30%, it was recently cut to 15%.

Renewable Energy Certificates: Renewable Energy Certificates (RECs) are tradeable certificates for use as incentive to those who generate green/solar power by providing financial incentives for every unit generated.

Net Metering Incentives: Net metering incentives depend on a) whether the net meter is installed b) the incentive policy of the utility company.

If there is a net metering incentive policy in a state and if there is a net meter on rooftop, then financial incentives for the power generated is a surity.

Assured Power Purchase Agreement (PPA): The state and central power distribution and purchase guarantee the purchase of solar power as and when it is produced. The PPAs offer a high price equal to that of the peaking power on demand for solar power which is secondary power or negative load and a intermittent energy source on daily basis.

Solar Data Sharing and Accessibility Policy (SDSAP-2016) The mechanism for automated data quality control as per international norms is in place for quality control of SRRA data. To provide data to policy makers, solar power developers, R&D institutions; a solar policy was announced by MNRE known as the Solar Data Sharing and Accessibility Policy (SDSAP-2013).

1. NIWE operates and maintains SRRA stations as per relevant protocols. The data collected at SRRA field stations are transmitted to CRS at NIWE, Chennai and data is subjected to quality checks and is preserved at multiple locations in raw as well as processed form.
2. NIWE will disseminate limited data through its website. The following information is to be made available on the NIWE website:

• Map showing SRRA stations across India with tags, which when clicked by the users will pop out a small window to give stations basic parameters and previous month average values.
• Sample data files for a SRRA station.

1. NIWE/NISE is authorized to sell processed data of up to 25 SRRA stations to a single buyer (Indian/ foreign nationals/ R&D institutes/organizations) and receipts are be credited to SRRA account maintained by NIWE. For selling data of more than 25 SRRA stations, specific permission from MNRE is a must.
2. Data provided to buyers are for their exclusive use only and the data in full/part or any other form can be disclosed/copied/distributed/transferred/reproduced for use by other agencies either electronically or in a physical form. All parties procuring SRRA data must submit an undertaking as such.
3. MNRE is the sole and exclusive owner of the SRRA data, both in raw and processed form received at the CRS at NIWE, Chennai. Access to the data will be guided by the following principles:-

• Access to day-to-day data of each SRRA site for their use is subject to specific signing of Non-Disclosure Agreement (NDA).
• Publication of data in any form isn’t allowed, unless otherwise specified with written permission from MNRE through NIWE.

II. Data Policy

The raw data is available only for collaborative work with national/international Institutions to develop solar maps and other value added products under specific permissions from MNRE. After solar maps are developed these will be examined by a National Solar Radiation Expert Committee (NSREC) which consists of experts from MNRE, ISRO, NIWE, IMD, SEC, SECI, IIT and other well known institutes under Chairmanship of Joint Secretary (NSM),MNRE.

The cost for various SRRA data products are as follows. *Above charges would be subject to levy of service tax and any other tax/cess levied by the Government from time to time.

Data from Indian Solar Radiation Atlas *Above charges would be subject to levy of service tax and any other tax/cess levied by the Government from time to time.3. The service tax (currently 15%) any other tax /cess as applicable levied by Government from time to time is also to be paid along with the data cost.

Data cost including taxes is to be paid in advance.* The revised price for solar data products is w.e.f.06.05.2016.4. The cost of data would remain the same even if anyone wants to procure data only for limited number of parameters.5. Academic/research institutes that procure SRRA data need to send an authorization letter on organizational letter head duly signed by Head of the Institution stating the reason that data is being procured solely for in-house research and will not be shared with any other organization.6.

Buyer should pay the amount only after being satisfying about the quality of the SRRA data.7. Under no circumstances money once paid for purchase of SRRA data will be returned to the buyer.8. In case, the buyer remits amount, SRRA can provide data for an equivalent alternate period or alternate stations data.9.

SRRA data would be sold either through CD /e-mail. About Vivaan Solar Vivaan Solar as a EPC contractor is a solar PhotoVoltaic system installer & integrator. We have installed 60 MW solar park in Madhya Pradesh, 5 MW in Punjab, 8 MW in Uttarakhand and an upcoming park in Karnataka. We are also MNRE accredited channel partner for Rooftop.

We have done turnkey works for multiple companies across the country and has third party agreements with some of the leading industries/commercial institutions across the state. We are an MNRE accredited channel partner. For more info you can visit our website:www.vivaansolar.com or mail [email protected].

What does W m2 measure?

What are the units of irradiance? : Vaisala provides various solar products for numerous purposes. The different physical quantities represented and the units used in these products can be somewhat confusing. You can change the units displayed in the Solar Prospecting Tools from W/m² to kWh/m²/day under the “Account” menu, located at the upper right of the screen.

In that menu under “Preferences” you can change the unit type displayed. Irradiance is a measurement of solar power and is defined as the rate at which solar energy falls onto a surface. The unit of power is the Watt (abbreviated W). In the case of solar irradiance, we usually measure the power per unit area, so irradiance is typically quoted as W/m², that is, Watts per square meter.

The irradiance falling on a surface can and does vary from moment to moment, which is why it is important to remember that irradiance is a measure of power – the rate that energy is received, not the total amount of energy. The total amount of solar energy that falls over a given time is called the insolation.

Insolation is a measure of energy. It is the power from the sun added up over some time period. Now here comes the confusing part. If the sun shines at a constant 1000 W/m² for one hour, we say it has delivered 1 kWh/m² of energy. The amount of power is the product of the power (1000 W/m²) times the length of time (1 hour), so that the unit of energy is the kWh.

Insolation (measured in kWh) is not the same as power (measured in kW) in the same way that miles per hour is not the same as miles. Another commonly used term is “peak sun hours,” which reflects the energy received during total daylight hours as defined by the equivalent number of hours it would take to reach that total energy value had solar irradiance averaged 1000 W/m².