The earth intercepts a lot of the sun’s power, receiving around 173 000 terawatts of solar energy, 10 000 times more power than the population uses. How do solar panels convert solar energy into electricity?
To answer this question, we have provided you an awesome video from Ted-Ed which explains in detail how this conversion happens.
Key take-aways from the video are:
1. They have small solar cells made of silicon which is a semiconductor, and these cells are bonded together so that electrons cannot escape.
2. Each cell is basically a sandwich made up of two slices of semiconducting material, usually silicon.
3. The sun shoots out particles of light called photons which when it hits an electron from its bond leaves a hole in the bond. The negatively charged electron and the positively charged photon are now free to move around but because of the electric field at the P/N junction, they will only go one way.
4. Each silicon cell only puts out half a volt but strung together, many modules can power houses, buildings and even cities.
5. The most efficient solar cell yet still only converts 46% of sunlight to electricity and most commercial solar panels are only 15 – 20% efficient
Further interesting facts about solar
- Solar panels produce direct current (DC), not alternating current (AC) electricity
- To work, phosphorus is seeded into the top layer of silicon to add extra electrons with a negative charge and the bottom layer gets a dose of boron which results in fewer electrons, or a positive charge which adds up to an electric field at the junction between the silicon layers
- There a few different types of solar including solar thermal and concentrated solar power which operate differently to photovoltaic solar panels