Solar Photovoltaic (PV) – Milking the sun

Within this blog, we will talk about solar photovoltaic (PV) by starting to elaborate on basic knowledge facts and get deeper into the rabbit hole by focusing on all aspects of this technology.

The French scientist Edmond Becquerel has first discovered the photovoltaic effect in 1839 while experimenting with an electrolytic cell made up of two metal electrodes placed in an electricity-conducting solution; The electricity generation increased when the system has been exposed to light. Given this discovery, the cornerstone was laid for milking the sun; however, it lasted until the year of 1954 when Daryl Chapin, Calvin Fuller and Gerald Pearson built the first silicon solar cell of 6% efficiency.

Solar-electricity is generated by sunlight (solar radiation) hitting semiconductors within the PV cell. As a result, electrons are freed and form an electric current to get the juice flowing. To trigger the photovoltaic effect, various semiconductor materials can be used; however, the most common nowadays is still silicon. Other variations of substances being tested and experimented with, for increasing the efficiency of PV are (i) Monocrystalline Silicon – 26.7% efficiency, (ii) Multicrystalline Silicon – 22.3% efficiency, (iii) Amorphous Silicon – 15% efficiency, (iv) Cadmium Telluride (CdTe) – 21% efficiency and (v) Copper Indium Gallium Selenide (CIGS) – 23.4% efficiency^[1]. Recent studies show promising results with alloys of III-V semiconductors claiming to be able to construct solar cells with 47.1% efficiency^[2].

The first use case of solar cells has been implemented to power space satellites in 1958 when Vanguard I has been adjusted with six solar cells mounted on the outer surface. The array produced about one watt of power for over six years. Nowadays, PV is the primary power supply of satellites orbiting the earth due to drastically increased efficiency^[3].

In modern society, PV is an inherent part of energy conversion, competing heavily against fossil fuels all over the world. In the UK, Solar PV has recently proven several times of being capable of contributing more than 25% of the electricity demand to the entire country on peak production of a sunny day^[4]. Besides, Solar is getting more and more attention amongst citizens due to its various capabilities, e.g. (i) residential as a roof-top or built-in application, (ii) commercial installations, (iii) utility-scale solar parks, and (iv) divers daily routine applications to power a smartphone or simply place some solar garden lamps.

The global solar photovoltaic capacity has increased massively within the last two decades, with a worldwide capacity of approx. five GWp in 2005 to some 509.3 GWp in 2018^[5]. This rapid development can be traced to the enormous potential solar PV embodies, as well as the continuously increasing efficiency rates and ongoing funding of this relatively new technology.

Last but not least, we want to mention the unreal potential of Solar PV. The total amount of solar radiation reaching the earth every day equates to approx. 10,000 times the world’s total energy use. The challenge herby is the cost-effective conversion and options to ”store” the generated energy^[6].

What are your thoughts on electrifying the immense potential of Solar PV?

^[1] https://www.statista.com/statistics/677062/efficiency-of-solar-cells-by-type/

^[2] https://www.pv-magazine.com/2020/04/14/six-junction-iii-v-solar-cell-with-47-1-effiency/

^[3] https://www.worldscientific.com/doi/abs/10.1142/S0217984901002038

^[4] https://apps.apple.com/gb/app/gridcarbon/id346832866

^[5] https://www.statista.com/topics/993/solar-pv/

^[6] https://phys.org/news/2011-10-vast-amounts-solar-energy-earth.html#jCp