The average efficiency of solar panels is typically determined by measuring the amount of energy that individual solar cells are able to convert into usable power. For example, an average silicon solar cell has an optimal efficiency rating of about 15%. This means that it can generate enough electrical power to provide for all the energy needs of an average home.

Where Does the Energy Come From?

The sun releases energy in the form of photons. Photons have different wavelengths which determine their energy carrying capacity. The smaller the wavelength, the more energy the photon can hold. The photons, in turn, activate the solar cell’s electrons in order to create an electrical current.

You need 1.1 electron volts of energy in a photon in order to release an electron from silicon. If more electron volts are released, the solar cells won’t know what to do with it and will just release it as extra heat. This is obviously a very inefficient system because the solar cells can only harness a limited amount of energy at a time.

How Much Power is Provided by the Sun?

The amount of solar energy that you can harness depends on your geographical positioning on the Earth. In order to rate the power generating ability of a solar panel, certain calculations have to be applied according to AM1.5 standard conditions. AM1.5 is short for air mass 1.5 and it’s considered to be the perfect conditions under which you can test the average efficiency of solar panels because it implies that the sun is generating 1,000 watts of energy per square meter. Nevertheless, the amount of solar energy that’s available will still fluctuate due to weather conditions, specific location and the time of the day.

How Much Sun Power Can Solar Cells Use?

Solar energy experts use a radiation model known as the blackbody spectrum to understand the way solar energy works. What makes the blackbody spectrum so effective at this task is the fact that it’s able to accurately describe the energy distribution of an object based on varying wavelengths.

The blackbody spectrum tells us that 23% of the sun’s energy is virtually useless because it has a super long wavelength that cannot be processed by solar panels. As a result, its photons simply go right through the cell almost undetected.

An additional 33% of the solar energy that’s harnessed through solar panels is practically unusable because it’s considered to be excess energy. At the end of the day, the silicon cells can only harvest about 44% of the sun’s energy. This gets filtered further through internal processes of the cell such as reflection. This leaves about 15% of usable energy left.

How to Increase Panel Efficiency?

At present, the only viable method available to improve solar panel efficiency is to use better quality materials when constructing the panels. This can be done through the combination of two or more different materials to create a hybrid panel that’s able to maximize the average efficiency of solar panels.

The only downside to this solution is that it would significantly increase manufacturing costs, thus transferring that increase to the consumer.


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