While the word ‘solar’ in solar panels speaks for itself, your PV modules don’t go to sleep even in the darkest of the nights. The question is whether a solar system can generate a noticeable amount of power while you’re asleep. Below we take a look at the dark side of solar panels: how they work in extremely low-light conditions, i.e. during the night or in overcast weather.
FAQ – How do solar panels work?
The photovoltaic effect is the core principle behind solar panels. To generate power, silicon solar cells need to be bombarded with photons. These light particles force electrons in the PV module material to move faster and thus generate direct current. This is the mechanism in a nutshell. You may also take a look at a more detailed answer to the ‘how do solar panels work’ question.
Do solar panels work on cloudy days?
First of all, not all clouds are made equal. Some very rare types can even boost electricity production by concentrating sunlight above your house due to reflective properties. However, in the majority of cases you should expect a rather sharp reduction in your solar harvest. When heavy clouds are in the sky, you can expect the performance to drop 70% to 90%, depending on how bad the weather is and how good the panels are.
How do solar panels work on winter days?
However surprising, the answer is your solar panels will perform better in winter given the same amount of sun. This is due to the fact that PV modules start losing efficiency once heated to 77°F and above. Heat is ot a problem in winter, but due to shorter days and sometimes cloudier weather your system isn’t very likely to beat its summer records. Still, this factor allows solar panels to produce a substantial amount of energy even in winter.
How do solar panels work at night?
Artificial light sources, the Moon and the stars certainly direct some light at your panels. Unfortunately, the electricity that can be produced with it is negligible, so the answer is negative. However, if by asking ‘how do solar panels work at night’ you mean the PV system as a whole, the answer will be very different. With enough panels and storage capacity, you could have enough power for the whole night or even a few days.
The Future: Anti-Solar Panel
There is a possibility we will answer the question ‘how do solar panels work at night’ very differently in the future. The concept of anti-solar panels is a topic of interest for many scientists. The principle is simple: when the sun is gone, objects and surfaces start to radiate the heat outwards, and this heat can be captured. The best prototypes of anti-solar panels currently produce about 2.2W per square meter and don’t require any storage or batteries. Given the power output, the technology seems too raw for practical applications, but this can change very fast given the pace of development.
