From Springer Nature:
Between now and 2018 the photovoltaic solar panel industry will have avoided more greenhouse gases emissions than it has released in the past 40 years of development, and produced more energy than it consumed, shows modelling in a study published this week in Nature Communications. The study concludes that solar panels are a net benefit in producing clean energy.
The solar panel industry aims to achieve cleaner energy production, but it consumes energy and emits greenhouse gases during production and deployment. However, as the industry has developed, the production of solar panels has become more efficient. Wilfried van Sark and colleagues study the industry globally between 1976 and 2014, and show that every doubling of installed photovoltaic capacity resulted in a decrease of energy usage during production and deployment by around 12–13 per cent and a decrease in greenhouse gas emissions by around 17–24 per cent, depending on the material used in the panels. This means that the industry has most likely paid its energy and greenhouse gases debts already, or if not, is very close to doing so.
The authors look at full life-cycle assessments of solar panels and compare their models to databases from the United Nations and the International Energy Agency. They also analyse the uncertainties of their models: in their worst case scenario, the energy debt will be paid by 2017 and the greenhouse gas debt by 2018.