Evaluation upon the Energy Resources of Photovoltaic Systems depending on their Location

The year 2020 will be remembered as a year of turbulences. Our towns have been devastated by the pandemic, but the environment benefited from the drastic reduction in fossil fuel use. Citizens and civil society pressure led the courts to push governments to enhance their own climate policies, while the private sector purchased high ever quantities of renewable energy. The results of this study are once again an argument for the decisive share that photovoltaic energy must have in the balance of the future. For the fastest possible recovery of investment in renewable sources (the so-called Energy Payback Time-EPBT parameter) but also for the effective reduction of greenhouse gas emissions (acronym GHG, mainly CO
2
), photovoltaic systems are one of the most sustainable and inexhaustible solutions. All despite the fact that their energy efficiency is strongly influenced by the location, having a degree of unpredictability dictated by the proverbial whims of weather. Our study is a comparative one. There are two main options for photo-voltaic (PV) systems: monocrystalline (mono-Si) and multicrystalline (multi-Si). We have chosen two different cities in Romania, a northern city (Iasi) and a southern one (Constanta). There are analyzed two essential elements: one from environmental perspective-the quantity of greenhouse gas (expressed in g of CO
2
directly or not produced for an energy of 1 kWh) and the second mainly financial, the EPBT. Due to solar radiation and the technical solution adopted, our calculations show that CO
2
, eq/kWh varies between 0.27 and 0.36 g range and the EPBT might varies from 1.33 to 1.54 years.