Rooftop Photovoltaic Energy Production Management in India Using Earth-Observation Data and Modeling Techniques

Abstract

This study estimates the photovoltaic (PV) energy production from the rooftop solar plant of the National Institute of Technology Karnataka (NITK) and the impact of clouds and aerosols on the PV energy production based on earth observation (EO)-related techniques and solar resource modeling. The post-processed satellite remote sensing observations from the INSAT-3D have been used in combination with Copernicus Atmosphere Monitoring Service (CAMS) 1-day forecasts to perform the Indian Solar Irradiance Operational System (INSIOS) simulations. NITK experiences cloudy conditions for a major part of the year that attenuates the solar irradiance available for PV energy production and the aerosols cause performance issues in the PV installations and maintenance. The proposed methodology employs cloud optical thickness (COT) and aerosol optical depth (AOD) to perform the INSIOS simulations and quantify the impact of clouds and aerosols on solar energy potential, quarter-hourly monitoring, forecasting energy production and financial analysis. The irradiance forecast accuracy was evaluated for 15 min, monthly, and seasonal time horizons, and the correlation was found to be 0.82 with most of the percentage difference within 25% for clear-sky conditions. For cloudy conditions, 27% of cases were found to be within ±50% difference of the percentage difference between the INSIOS and silicon irradiance sensor (SIS) irradiance and it was 60% for clear-sky conditions. The proposed methodology is operationally ready and is able to support the rooftop PV energy production management by providing solar irradiance simulations and realistic energy production estimations.

Impact of Aerosol and Cloud on the Solar Energy Potential over the Central Gangetic Himalayan Region

“…However, the attenuation increases to moderate from 16 to 20% during the seasonal AOD peak in July-August, followed by lower energy production levels. These results are consistent with 10-25% attenuation over South Asia from the work reported by several authors [71,86]. From the study of multi-year data, the estimated diurnal peaks of CAMS, GHI, and BHI exhibit around 300-700 Wm −2 during 5-6 UTC during the spring-summer season.…”

“…The range of GHI percentage attenuation was found to be 0 to 14%, whereas the corresponding BHI percentage attenuation values vary from 0 to 20%. These results are quite similar to the previous results which are comparable with a similar approach [70,71]. The results are quite important data for irradiance attenuation over the Indian subcontinent region [76][77][78].…”

“…The financial analysis was performed by simulating a hypothetical scenario of a PV and a CSP system with nominal power of 1 MW assumed to be installed in CGHR following the methodology described in [70]. During the estimation of PV energy production, we assumed that the PV material (which is silicon polycrystalline) has an efficiency of 16% and a shadowing effect of 4% from the surroundings [71]. Therefore, the remaining efficiency of 80% has been converted to PV output energy based on the nominal power and electricity converter technology and AC/DC efficiency.…”

“…To perform the financial analysis of PV and CSP energy production, there is a need for electricity generation price in INR per kWh (1 INR ≈ 0.013 USD). The PV as well as the CSP output energy is converted into the price of electricity as follows the earlier energy by [70,71]:…”

“…Figure 10a,b shows the financial analysis results for Nainital, a high-altitude remote location in the central Himalayan region, on the hypothetical 1 MW system by following the methodology given in several earlier papers [70,71]. Here, the economic and energy impact was quantified in terms of monthly means, total energy losses (EL), financial losses (FL), and solar energy potential.…”