aarab.boujemaa2018

Hi everybody; I worked for 3 years in photovoltaics, currently there are 3 sites that have been in operation for a year, The problem I noticed is that I still find a considerable gap of 30% between the theoretical production simulated and real production. is it normal ?, is it possible to reduce this gap to maximum 10% . If you want more informations I can communicate them to you. Thank you very much.