If carbon emissions are a debt, solar panels will soon be able to pay off their share.
For almost endless sunshine, the solar panel industry aims at achieving cleaner energy production. But in the process of production and laying, it also consumes energy and emits greenhouse gases. When the early technology is relatively primitive and the production efficiency is low, the output energy is lower than the consumption of the manufacturing process, and a large number of greenhouse gases are produced. It can be said that in the early stage of this technology development, solar panels owe two aspects of "energy consumption" and "carbon emissions".

A) world and b) photovoltaic power generation capacity in several countries, and C) the proportion of PV equipment in various countries (%).
Van Sark et al.

However, with the development of science and technology, the reduction of greenhouse gas emissions from solar panels and the increase of productivity efficiency are constantly making up for the consequences of the early technical limitations. In fact, according to the study published this week in nature - communications, Re-assessment of net energy production and greenhouse gas emissions avoidance after 40 years, the solar panels are now "paying off the debt". From now to 2018, the solar panel industry will avoid greenhouse gas emissions that will exceed the industry's greenhouse gas emissions in the past 40 years and produce more energy than it consumes. This study argues that solar panels bring net benefits to clean energy production.

The a of photovoltaic devices) net energy output and b) reduction of greenhouse gas emissions.
Van Sark et al.

Wilfried van Sark of the University of Utrecht in Holland and colleagues studied the development of the global solar panel industry between 1976 and 2014, and found that the energy consumption of producing and deploying solar panels will decrease by about 12-13% when the capacity of photovoltaic power is doubled, and the emission of warm room gas will decrease by 17-24%. The material used in the battery board. This means that the industry is probably already paying off the "debt" of energy consumption and greenhouse gas emissions. Even if not, the balance is close.

The authors evaluated the life cycle of the solar panel industry and compared their models with the databases of the United Nations and the International Energy Agency. They also analyzed the uncertainties in the model, and the results showed that, even in the worst case, the industry would also reduce energy consumption in 2017 and pay off the "debt" of greenhouse gas emissions in 2018. It