Depends on what panel you want to use. Basically you take your solar radiation data (W/m2) - per unit of time. This means that if a site gets 1000W/m2 of irradiation, the energy falling onto that surface in 1 hour is 10kWh. If you have a panel that is 1m2 and has a conversion efficiency of 10%, then what you could get out of this surface area usefully with the panel is 1kWh. You will also need to adjust for the fact that you won't be covering the ground flat-out with panels, so there will be some "coverage factor", e.g. out of 100m2 area, only 70% will be covered with useful photovoltaic cells.
Dear Harendra: what type of data you have? is it monthly average? hourly data? is it global, direct, or diffuse solar radiation? However, three techniques are used to find the PV power: intuitive, numerical and analytical techniques. In the simulation technique there are around 35 well known software's used for this calculations. Enclosed are some of our research papers related to your question.
1. Hussein Kazem, Hamood A. S. Al-Badi, Ahmed S. Al Busaidi and Miqdam T Chaichan, “Optimum design and evaluation of hybrid solar/wind/ diesel power system for Masirah Island”, Springer - Environment, Development and Sustainability, ISSN: 1387585X, Netherlands, 2016, pp. 1-18.
2. Hussein Kazem, "Solar Radiation, Temperature and Humidity Measurements in Sohar-Oman", International Journal of Computation and Applied Sciences, vol. 1, Issue 1, pp. 15-20, 2016.
3. Ali H A Al-Waeli, Hussein Kazem, and Miqdam T Chaichan, “Review and Design of a Standalone PV System Performance," International Journal of Computation and Applied Sciences, vol. 1, Issue 1, pp. 1-6, 2016.
4. Hussein A. Kazem, Jabar H. Yousif and Miqdam T Chaichan, “Modelling of Daily Solar Energy System Prediction using Support Vector Machine for Oman”, International Journal of Applied Engineering Research, ISSN 0973-4562, India, Vol. 11 No.20 (2016) pp. 10166-10172.
5. Hussein A Kazem and Miqdam T Chaichan, “Experimental analysis of the effect of dust’s physical properties on photovoltaic modules in Northern Oman”, Elsevier-Solar Energy SE, (ISSN: 0038092X), UK, December 2016, Vol. 139, pp. 68-80.
6. Jabar H. Yousif and Hussein A. Kazem, “Modeling of Daily Solar Energy System Prediction using Soft Computing Methods for Oman”, Research Journal of Applied Sciences, Engineering and Technology USA, 2016, Vol. 13, Issue. 3, pp. 237-244.
7. Hussein A Kazem and Miqdam T Chaichan, “Effect of Environmental Variables on Photovoltaic Performance-Based on Experimental Studies”, International Journal of Civil, Mechanical and Energy Science (IJCMES), Vol. 2, Issue 4, September 2016, pp. 1-8.
8. Hussein A Kazem, Humaid Al-Badi, Ahmed Al-Busaidi, Miqdam T Chaichan, “Optimum design and evaluation of hybrid solar/wind/diesel power system for Masirah Island”, Springer - Environment, Development and Sustainability, ISSN: 1387585X, Netherlands, 2016, pp. 1-13.
9. Miqdam T Chaichan, Hussein A Kazem, “Experimental analysis of solar intensity on photovoltaic in hot and humid weather conditions”, International Journal of Scientific & Engineering Research, Vol. 7, Issue 3, March-2016, pp. 91-96.
10. Hussein A Kazem, Ali H A Al-Waeli, Miqdam T Chaichan, Asma S Al-Mamari Atma H Al-Kabi, “Design, Measurements and Evaluation of Photovoltaic Pumping System for Rural Areas in Oman”, Springer - Environment, Development and Sustainability, ISSN: 1387585X, Netherlands, 2016, pp. 1-13.
11. Hussein A Kazem, Ali H A Al-Waeli, Miqdam T Chaichan, Asma S Al-Mamari Atma H Al-Kabi, “Design, Measurements and Evaluation of Photovoltaic Pumping System for Rural Areas in Oman”, Springer - Environment, Development and Sustainability, ISSN: 1387585X, Netherlands, 2016.
12. Ali H. A. Al-Waeli, Moanis M Kamal El-Din, Atma H. K. Al-Kabi, Asma Al-Mamari, Hussein A Kazem, and Miqdam T Chaichan, “A photovoltaic application in car parking lights with recycled batteries: A techno-economic study”, Australian Journal of Basic and Applied Sciences (AJBAS), Pakistan, December 2015, Vol. 9, Issue 36, pp. 43-45.
13. Ahmed Said Al Busaidi, Hussein A Kazem, A. Al-Badi and Mohammad Farooq Khan, “A review of optimum sizing of hybrid PV–Wind renewable energy systems in Oman”, Elsevier-Renewable and Sustainable Energy Review (RSER, ISSN: 1364-0321), USA, 2016, Vol. 53, pp. 185-193.
14. Ammar Awada, Jagadeesh Pasupuleti, Tamer Khatib, and Hussein A Kazem, “Modeling and characterization of a photovoltaic array based on actual performance using cascade-forward back propagation artificial neural network”, Journal of Solar Energy Engineering: Including Wind Energy and Building Energy Conservation (ISSN: 01996231) June 2015, Vol 137, Issue 4, 5 pages; DOI: 10.1115/1.4030693, USA.
15. Hussein A. Kazem, Ali H. A. Al-Waeli, Atma H. K. Al-Kabi, and Asma Al-Mamari, “Techno-economical Assessment of Optimum Design for Photovoltaic Water Pumping System for Rural Area in Oman”, International Journal of Photoenergy (ISSN: 1110662X), Vol. 2015, Article ID 514624, 8 pages, USA.
16. Hussein A Kazem, Tamer Khatib, K. Sopian and Wilfried Elmenreich, “Performance and feasibility assessment of a 1.4kW roof top grid-connected photovoltaic power system under desertic weather conditions”, Elsevier-Energy and Building EB (ISSN: 03787788), Netherlands, 2014, Vol. 82, pp. 123-129.
17. Samara Qasim Ali Al-Asadiand and Hussein A Kazem, “Feasibility Study of Photovoltaic/Wind/Battery Hybrid System for Oman”, Engineering Science and Technology (ESTIJ), Vol. 3, No. 3, 2013, pp. 466-470.
18. Hussein A. Kazem, and Tamer Khatib, “Techno-economical assessment of grid connected photovoltaic power systems productivity in Oman”, Elsevier-Sustainable Energy Technologies and Assessments, Vol. 3, 2013, pp. 61–64.
19. Tamer Khatib, K. Sopian, and Hussein A Kazem, “Actual performance and characteristic of a grid connected photovoltaic power system in the tropics: A short term evaluation”, Elsevier-Energy Conversion and Management, (ECM, ISSN: 0196-8904), UK, Vol. 71, 2013, pp. 115–119.
20. Majid Alabdul Salam, Ahmed Aziz, Ali H A Alwaeli, and Hussein A. Kazem, "Optimal Sizing of Photovoltaic Systems Using HOMER for Sohar, Oman", International Journal of Renewable Energy Research (IJRER), Turkey, March 2013, Vol. 3, No. 2, pp. 301-307.
21. Hussein A. Kazem, and Tamer Khatib, “A novel numerical algorithm for optimal sizing of a photovoltaic/wind/diesel generator/battery microgrid using loss of load probability index”, International Journal of Photoenergy, USA, March 2013, 8 pages.
22. Hussein A. Kazem, Tamer Khatib, and K. Sopian, “Sizing of a standalone photovoltaic/ battery system at minimum cost for remote housing electrification in Sohar, Oman”, Elsevier-Energy and Building, Netherlands, 2013, Vol. 6C, pp. 108-115.
You can download for free RETScreen expert .There are tutorials and case studies for all energy conversion projects, PV included. You can also find the theoretical bases of the software .
Refer equation 6 and 7 of paper "2011 IEEE Transactions on Sustainable energy Optimal Power Flow Management for Grid Connected PV Systems With Batteries"